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Courtship behavior during heterosexual and homosexual consortships in Japanese macaques. Behavioral Processes, 78, 401-407
Abstract
Female Japanese macaques (Macaca fuscata) in the Arashiyama population near Kyoto, Japan, are unusual, in that they exhibit what many would consider to be male-typical sexual characteristics. Specifically, they mount other females within the context of temporary, but exclusive, sexual relationships (i.e., homosexual consortships) and they sometimes exhibit a preference for female sexual partners, even when given the choice of a sexually motivated male alternative. In this study, we examined whether female Japanese macaques also exhibited male-typical patterns of courtship behaviour during homosexual consortships. Data were collected on courtship behaviour during heterosexual and homosexual consortships in free-ranging Japanese macaques from the Arashiyama (Japan) population. We analyzed the occurrence of 12 different courtship behaviours during 3374 heterosexual inter-mount intervals and 1412 homosexual inter-mount intervals. Sex differences between heterosexually consorting males and females existed for only two of the 12 courtship behaviours we investigated: inclined-back presentations and sexual vocalizations. Dominant and subordinate homosexually consorting females were sex-typical in their expression of inclined-back presentations and sexual vocalizations. Consequently, facultative same-sex sexual partner preference, mounting and consortships do not co-occur with male-typical patterns of courtship behaviour in female Japanese macaques.
... To date, the hypothesis that FMM is a form of courtship that may function to trigger MFM has not been formally tested (e.g., via a sequential analysis of sexual behaviours) and systematically examined in an observational research setting. Until now, there is no empirical evidence that FMM is as efficient as, or even more efficient (i.e., a female-to-male 'supernormal courtship' behavioural pattern) than species-typical female-to-male sexual solicitations (hereafter FMSS, such as pushing, ground-smacking, body spasm, and shrieking vocalizations; Vasey et al., 2008a;Wolfe, 1979) in non-experimentally manipulated animals. A phenotypic stimulus (e.g., behavioural trait) is defined as 'supernormal' if it triggers the expression of the normal pattern of behaviour even more strongly than the normal stim-ulus (Tinbergen, 1951). ...
... In certain populations of Japanese macaques (Macaca fuscata), adult females are bisexual, routinely engaging in both sexual interactions with adult opposite-sex and same-sex mates within the context of temporary, but exclusive, sexual associations during the mating season, known as consortships (Gouzoules & Goy, 1983;Huffman, 1991Huffman, , 1992Vasey, 2006;Leca et al., 2014a;Wolfe, 1979). Sexual behaviours expressed during such consortships include vocal, facial, and gestural sexual solicitations, and mounting behaviours, including FFM, FMM, and MFM (Vasey et al., 2008a;Leca et al., 2015;Gunst et al., 2020;Wolfe, 1979). In addition to sexual solicitations and mounting behaviours, consortships are characterized by a close spatial proximity between the two sexual partners. ...
... However, in these analyses, we did not distinguish between different mounting postures. Sexual solicitations (or courtship behaviours) occurred during inter-mount intervals and functioned to prompt mounting behaviour (Vasey et al., 2008a). Inter-mount intervals were defined as the period between two consecutive mounts. ...
We analysed heterosexual consortships in a free-ranging group of Japanese macaques in which adult females routinely perform female-to-male mounting (FMM). We tested whether FMM is more efficient (i.e., a ‘supernormal courtship’ behavioural pattern) than species-typical female-to-male sexual solicitations (FMSS) at prompting subsequent male-to-female mounts (MFM). In a context of high female-female competition for male mates, we found that (1) FMM functioned to focus the male consort partner’s attention as efficiently as FMSS and prevented him from moving away, and (2) FMM was more efficient than species-typical FMSS at expediting MFM (i.e., the most fitness-enhancing sexual behaviour of a mating sequence). We concluded that FMM could be considered a supernormal courtship behavioural pattern in adult female Japanese macaques. This population-specific sexual adaptation may result from a combination of favourable socio-demographic conditions. This study has implications for the evolutionary history of non-conceptive mounting patterns in Japanese macaques and non-conceptive sexuality in humans.
... For most of these analyses (except the data set used to test Prediction #3b), we selected 10 adult females, whose age range was 7 -21 years (mean ± SD = 13.2 ± 4.9 years). These subjects were representative of adult female Japanese macaques at Arashiyama, with regards to the degree of heterosexual activity exhibited and the range of sexual behaviors performed [11,16,24,25]. Each subject was selected during one of the three study periods. ...
... The first author (NG) was the sole video-scorer of all the mating sequences, and used a composite ethogram for heterosexual consortships in Japanese macaques [11,16,22,[24][25][26][27][28]. NG used The Observer XT 12 (by Noldus) to score the video-recorded mating sequences and generate event-log files (i.e., series of consecutive behavior patterns) for each subject. ...
... p = 0.114). The number of different series of behavior patterns (i.e., Tpatterns of unique composition) in mating sequences with FMM (i.e., 24) was not significantly different from that in mating sequences without FMM (i.e., 20). Moreover, there were numerous structural similarities in the contents of the T-patterns detected in each group of behavioral sequences (Fig. 4). ...
In certain populations of Japanese macaques, adult females mount adult males in the context of heterosexual consortships (i.e., temporary but exclusive sexual associations between a male and a female). Previous research suggested that, in this primate species, female-male mounting (FMM) may be a behavioral adaptation. This functional hypothesis holds that FMM is a (special) courtship behaviour, or a (super) sexual solicitation, that serves the function of focusing the male's attention, preventing him from moving away, and expediting male-female mounting, in the context of high female competition for male mates. In this study, we aimed to test some of the proposed functional features of FMM in Japanese macaques by comparing the temporal structure of mating behavioral sequences, including various well-known sexual solicitations, exhibited during heterosexual consortships with and without FMM. To identify and compare recurring series of behavioral events within and across sequences, we used a temporal analysis known as "T-pattern detection and analysis". Our results (partly) supported the "FMM as a (super) sexual solicitation" hypotheses, and supported the "FMM as a sexual adaptation" hypothesis. The utilization of TPA allows for the detection of hidden features of primates' behaviors otherwise undetectable by using conventional quantitative approaches, such as the calculation of frequencies or durations of isolated behavioral components, disjointed from the comprehensive behavioral architecture. This study fits into the scheme of a broader investigation of the functionality of non-conceptive mounting patterns observed in Japanese macaques and a reconstruction of their evolutionary history.
... Contract grant sponsor: Natural Sciences and Engineering Research Council of Canada (NSERC); contract grant sponsor: A l b e r t a I n n o v a t e s H e a l t h S o l u t i o n s ( A I H S ) ; contract grant sponsor: Japan Society for the Promotion of Science (JSPS); contract grant sponsor: American Institute of Bisexuality (AIB); contract grant sponsor: L.S.B. Leakey Foundation; contract grant sponsor: Office of the Dean of Arts and Science; contract grant sponsor: Office of Research Services at the University of Lethbridge Ethical standards: All research methods were approved in accordance with the Guide for the Care and Use of Primates prepared by the Primate Research Institute, Kyoto University. of sexual behavioral patterns, and the range of sexual partners. The free-ranging Arashiyama group of Japanese macaques (Macaca fuscata) located near Kyoto city, Japan, is an ideal nonhuman primate population for developmental research on sexual behavior because, in addition to engaging in reproductive sexual interactions [Pavelka & Fedigan, 1999], adult females in this group routinely exhibit various forms of homosexual and heterosexual non-conceptive sex, including same-sex solicitation and mounting be- haviors [Vasey, 2002; Vasey et al., 2008a] and female–male mounting [Vasey & Duckworth, 2008]. Even though female homosexual behavior occurs in other species and in other populations of Japanese macaques, it is highly frequent the Arashiyama group of Japanese macaques, which makes this group of nonhuman primate species amenable for quantitative study and hypotheses testing [Leca et al., 2014b]. ...
... Most partners soliciting adolescent females for sex should be adult females (Prediction #2c). The " numerous homosexual adult females " hypothesis was inspired by previous research showing that at any point in time during the mating season, a substantial percentage of adult females are available and willing to mate with other females in the Arashiyama group of Japanese macaques [Vasey et al., 2008a]. Therefore, this hypothesis may explain not only adolescent females' but also adult females' high propensity to engage in homosexual consortships in this group. ...
... The routine occurrence of homosexual consortships between adult females of this group, with conspicuous displays of adult female–female courtship behaviors (including ground smacking, body spasms, and loud sexual vocalizations) and a variety of adult female-to-female mounting postures [cf. Vasey et al., 2008a], could attract the interest of sexually motivated adolescent females and promote the early expression of female homosexual behavior, via a social facilitation process [Leca et al., in press]. This hypothesis is derived from research on the social transmission of courtship behavior and mating preferences in numerous fish, bird and mammal taxa, including nonhuman primates [Freeberg, 2004; Nishida, 1980; Rees, 2004; Warner, 1990]. ...
We aimed to explain the frequent and prevalent female homosexual behavior in the context of female-biased operational sex ratios (OSR) and qualified sex ratios (Q) in a free-ranging group of Japanese macaques (Macaca fuscata) living at Arashiyama-Kyoto, Japan. Our data included the average availability of sexually mature males during females' putative fertile period (OSR), the ratio of sexually mature males to sexually mature females (Q), as well as heterosexual and female homosexual solicitations and consortships collected during 13 mating seasons from 136 females. Our results did not support the ''heterosexual deprivation hypothesis,''which holds that female homosexual behavior is attributable to a shortage of male mates. Likewise, our results did not support the ''lack of opposite-sex sexual competitor hypothesis,'' which holds that females have more access to female mates when male sexual rivals are scarce. Of the 11 predictions tested, only one yielded statistically significant results: we found that higher ratios of availability of preferred female partners to preferred male partners were associated with female homosexual consortships rather than female heterosexual consortships. This result supported the ''bisexual preference hypothesis,'' which holds that female homosexual behavior is attributable to female preference for certain female mates relative to certain male mates. We conclude that when a female targets another female as a mate, it is an active choice for a female sexual partner over available male alternatives, rather than a by-default situation that occurs because males are not available as sexual partners, or because females are better able to access female sexual partners due to a scarcity of male sexual competitors. Keywords Operational sex ratio Á Qualified sex ratio Á Female homosexual behavior Á Bisexual preference Á Non-human primates
... For example, mounts performed by young female gorillas have been described as''mechanically difficult''(Fischer & Nadler, 1978).The nascent expression of mounting behavior by immature female primates suggests that early practice of behavioral precursors is necessary before fully adult patterns of sexual behavior can be performed. The free-ranging Arashiyama group of Japanese macaques (Macaca fuscata) located northwest of Kyoto city, Japan, is an ideal non-human primate population for developmental research on sexual behavior because, in addition to engaging in reproductive sexual interactions (e.g., Pavelka & Fedigan, 1999; Vasey, Foroud, Duckworth, & Kovacovsky, 2006; Vasey, Rains, VanderLaan, Duckworth, & Kovacovsky, 2008a), adult females in this group routinely exhibit various forms of homosexual, heterosexual, and solitary non-conceptive sex, including samesex solicitation and mounting behaviors (Vasey, 2002Vasey, , 2004Vasey, , 2006 Vasey et al., 2008a; Vasey, VanderLaan,Rains,Duckworth,&Kovacovsky,2008b),female– male mounting (Gouzoules & Goy, 1983; O'Neill, Fedigan, & Ziegler, 2004; Vasey & Duckworth, 2008 ), and masturbation (Wolfe, 1979 ). Structurally, homosexual behavioral patterns in adult females are very similar to typical heterosexual behavior (Vasey et al., 2008a, b), with same-sex courtship and behavioral variants in mounting postures occurring during temporary , but exclusive, sexual relationships (i.e., consortships: Vasey,2006).Althoughsame-sexmountingamongadultfemales is common at Arashiyama (but not at other sites: Vasey & Jiskoot, 2010 ), it does not seem to serve any obvious sociosexual function (Vasey, 2006). ...
... For example, mounts performed by young female gorillas have been described as''mechanically difficult''(Fischer & Nadler, 1978).The nascent expression of mounting behavior by immature female primates suggests that early practice of behavioral precursors is necessary before fully adult patterns of sexual behavior can be performed. The free-ranging Arashiyama group of Japanese macaques (Macaca fuscata) located northwest of Kyoto city, Japan, is an ideal non-human primate population for developmental research on sexual behavior because, in addition to engaging in reproductive sexual interactions (e.g., Pavelka & Fedigan, 1999; Vasey, Foroud, Duckworth, & Kovacovsky, 2006; Vasey, Rains, VanderLaan, Duckworth, & Kovacovsky, 2008a), adult females in this group routinely exhibit various forms of homosexual, heterosexual, and solitary non-conceptive sex, including samesex solicitation and mounting behaviors (Vasey, 2002Vasey, , 2004Vasey, , 2006 Vasey et al., 2008a; Vasey, VanderLaan,Rains,Duckworth,&Kovacovsky,2008b),female– male mounting (Gouzoules & Goy, 1983; O'Neill, Fedigan, & Ziegler, 2004; Vasey & Duckworth, 2008 ), and masturbation (Wolfe, 1979 ). Structurally, homosexual behavioral patterns in adult females are very similar to typical heterosexual behavior (Vasey et al., 2008a, b), with same-sex courtship and behavioral variants in mounting postures occurring during temporary , but exclusive, sexual relationships (i.e., consortships: Vasey,2006).Althoughsame-sexmountingamongadultfemales is common at Arashiyama (but not at other sites: Vasey & Jiskoot, 2010 ), it does not seem to serve any obvious sociosexual function (Vasey, 2006). ...
... The free-ranging Arashiyama group of Japanese macaques (Macaca fuscata) located northwest of Kyoto city, Japan, is an ideal non-human primate population for developmental research on sexual behavior because, in addition to engaging in reproductive sexual interactions (e.g., Pavelka & Fedigan, 1999; Vasey, Foroud, Duckworth, & Kovacovsky, 2006; Vasey, Rains, VanderLaan, Duckworth, & Kovacovsky, 2008a), adult females in this group routinely exhibit various forms of homosexual, heterosexual, and solitary non-conceptive sex, including samesex solicitation and mounting behaviors (Vasey, 2002Vasey, , 2004Vasey, , 2006 Vasey et al., 2008a; Vasey, VanderLaan,Rains,Duckworth,&Kovacovsky,2008b),female– male mounting (Gouzoules & Goy, 1983; O'Neill, Fedigan, & Ziegler, 2004; Vasey & Duckworth, 2008 ), and masturbation (Wolfe, 1979 ). Structurally, homosexual behavioral patterns in adult females are very similar to typical heterosexual behavior (Vasey et al., 2008a, b), with same-sex courtship and behavioral variants in mounting postures occurring during temporary , but exclusive, sexual relationships (i.e., consortships: Vasey,2006).Althoughsame-sexmountingamongadultfemales is common at Arashiyama (but not at other sites: Vasey & Jiskoot, 2010 ), it does not seem to serve any obvious sociosexual function (Vasey, 2006). Instead, its expression is associated with immediate sexual reward, which occurred via genital stimulation ( Vasey & VanderLaan, 2012). ...
We used cross-sectional focal data collected in adolescent and adult females to elucidate the comparative development of heterosexual and homosexual behaviors in female Japanese macaques (Macaca fuscata) living at Arashiyama, Japan, in a group where adult females routinely exhibit sexual interactions with both males and females. Our data fully or partially supported most of our predictions (20 out of 30) related to the "learning hypothesis," which postulated that adolescence would serve to provide young females with a period in which to practice, and gradually acquire, three types of adult female-like heterosexual and homosexual behavioral patterns, namely sexual solicitations, sexual mounts, and spatio-temporal coordination during consortships. However, there were marked differences in the development of heterosexual and homosexual behaviors. The percentage of homosexual mounts was significantly higher in adolescent than in adult females. Of the fully or partially supported predictions, 13 of 15 pertained to heterosexual activity whereas only seven of 15 pertained to homosexual activity. A number of sexual behavioral patterns (e.g., demonstrative solicitations, range of solicitation patterns and mounting postures, and grasping behavior during consortships) emerged earlier and developed faster when directed to females than when directed to males. We explain such differences in terms of risk of male aggression, males' disinterest in adolescent females' sexual solicitations, presence of motivated same-sex sexual partners, social facilitation, and sexual reward.
... In between mounting sequences, consort partners also engage in affiliative behaviors which are likely to influence the maintenance of their interactions. Behaviors characteristically shared during inter-mount phases are mutual following, social support, contact sitting, grooming and huddling (Vasey, 1998b;Vasey et al., 2008;Wolfe, 1984). Most of these behaviors imply body contact between two individuals. ...
... If a potential consort pair was found, the partners and their behaviors were recorded. We observed such pairs for 3 min, based on the reported average intermount interval of 1-2 min for Japanese macaques (Vasey et al., 2008). Female solicitation and inter-mount behavior were recorded and the direction of mounts categorized as male-female-mount (MFM), female-female-mount (FFM) or female-male-mount (FMM). ...
The Japanese macaque (Macaca fuscata) has become a key species for studying homosexual behavior over recent decades. With the non-conceptive nature, their same-sex consortships illustrate that individual partner preferences can exist beyond direct reproductive benefits or apparent sociosexual strategies. An open question is whether the behavior shared between partners in consortship directly affects their choice to remain with a partner. With this study, we examined behavioral aspects underlying consortship temporal patterns in these promiscuous and bisexual primates. While these patterns could be relevant in both homo- and heterosexual consortships, our study primarily focused on female-female pairs. We hypothesized that the stability of consortships (duration and occurrence) is influenced by a pair’s sexual behavior, mutual sexual stimulation, and close affiliative inter-mount behaviors involving high-intensity body contact. A semi-free population of Japanese macaques was observed over one mating season. In total, 40 h of focal data on female-female consortship behaviors were analyzed. Forty-six percent of all sexually mature females engaged in homosexual interactions. Our behavioral analyses of female-female pairs found that close body contact, rather than grooming or sexual interactions, was correlated with the stability of homosexual consortships. The greater the amount of huddling and embracing a pair engaged in, the more likely they were to stay together and reunite again. However, the frequency of mounting, rubbing or thrusting had no discernable effect on consortship stability. The results of this study thus add important knowledge to partner qualities in promiscuous primates as well as to inter-group differences of homosexual behavior in Japanese macaques.
... macaques, Macaca fuscata (Vasey et al., 2008). However, explaining the persistence of SSSB presents an evolutionary paradox, as SSSB cannot result in offspring and thus offers no direct fitness advantage (Bailey & Zuk, 2009). ...
... Nevertheless, the persistence of SSSB suggests that it may be an evolutionarily maintained characteristic rather than a chance occurrence (e.g. Bertran & Margalida, 2003;MacFarlane, Blomberg, Kaplan, & Rogers, 2006;Mann, 2006;Vasey, 2006;Vasey et al., 2008;Vervaecke & Roden, 2006). ...
Same-sex sexual behaviour (SSSB) occurs in animals ranging from insects to mammals, yet its evolutionary origins remain enigmatic. Is it adaptive, or has it evolved as a by-product of selection for other traits? Using data from two experiments on male spring field crickets, Gryllus veletis, we tested whether SSSB is socially adaptive, sexually adaptive, correlated with other sexual behaviours and/or a result of sex misidentification. By identifying how sexual experience, audience composition, mate attraction signalling time, body size/mass, food composition and aggression levels correlated with levels of SSSB, we found support for the misidentification and phenotypic correlation hypotheses. More aggressive males were more likely to court other males, and males who spent the most time signalling to attract mates tended to spend the most time courting other males, suggesting that aggression, mate signalling effort and same-sex courtship may all be phenotypically correlated. However, the positive relationship between mate attraction signalling effort and probability of expressing same-sex courtship only occurred in males on a high-carbohydrate, low-protein food, suggesting that the expression of such a phenotypic correlation may be constrained by dietary carbohydrate availability. Finally, males were more likely to be courted if they were less aggressive and spent little time signalling for mates, but, for the latter, only if they were on high-carbohydrate foods, suggesting that together, diet, which may alter chemical cues involved in sex identification, and behavioural cues may lead to sex misidentification. Thus, SSSB in male G. veletis does not appear to be adaptive, probably evolving instead as a by-product of selection for other sexually selected traits. By investigating both proximate and ultimate factors contributing to the evolutionary enigma of SSSB, we may gain important insights into the selective forces shaping aggression, social interactions and reproductive strategies in social animals.
... Contract grant sponsor: Natural Sciences and Engineering Research Council of Canada (NSERC); contract grant sponsor: A l b e r t a I n n o v a t e s H e a l t h S o l u t i o n s ( A I H S ) ; contract grant sponsor: Japan Society for the Promotion of Science (JSPS); contract grant sponsor: American Institute of Bisexuality (AIB); contract grant sponsor: L.S.B. Leakey Foundation; contract grant sponsor: Office of the Dean of Arts and Science; contract grant sponsor: Office of Research Services at the University of Lethbridge Ethical standards: All research methods were approved in accordance with the Guide for the Care and Use of Primates prepared by the Primate Research Institute, Kyoto University. of sexual behavioral patterns, and the range of sexual partners. The free-ranging Arashiyama group of Japanese macaques (Macaca fuscata) located near Kyoto city, Japan, is an ideal nonhuman primate population for developmental research on sexual behavior because, in addition to engaging in reproductive sexual interactions [Pavelka & Fedigan, 1999], adult females in this group routinely exhibit various forms of homosexual and heterosexual non-conceptive sex, including same-sex solicitation and mounting be- haviors [Vasey, 2002; Vasey et al., 2008a] and female–male mounting [Vasey & Duckworth, 2008]. Even though female homosexual behavior occurs in other species and in other populations of Japanese macaques, it is highly frequent the Arashiyama group of Japanese macaques, which makes this group of nonhuman primate species amenable for quantitative study and hypotheses testing [Leca et al., 2014b]. ...
... The routine occurrence of homosexual consortships between adult females of this group, with conspicuous displays of adult female–female courtship behaviors (including ground smacking, body spasms, and loud sexual vocalizations) and a variety of adult female-to-female mounting postures [cf. Vasey et al., 2008a], could attract the interest of sexually motivated adolescent females and promote the early expression of female homosexual behavior, via a social facilitation process [Leca et al., in press]. This hypothesis is derived from research on the social transmission of courtship behavior and mating preferences in numerous fish, bird and mammal taxa, including nonhuman primates [Freeberg, 2004; Nishida, 1980; Rees, 2004; Warner, 1990]. ...
We explored the role that sexual and social partners play in the expression of female homosexual behavior among adolescent female Japanese macaques at Arashiyama, Japan. Our data fully or partially supported all the predictions related to four non-mutually exclusive hypotheses, namely the “adult male disinterest in adolescent females” hypothesis, the “numerous homosexual adult females” hypothesis, the “safer homosexual interactions” hypothesis and the “same-sex sexual interactions” hypothesis. Our results show that both sexual context (e.g., lack of adolescent female attractivity toward adult males, presence of motivated same-sex sexual partners), and social context (e.g., risk of aggression) help explain the high frequency and prevalence of homosexual behavior in adolescent females in the Arashiyama group of Japanese macaques. As with adult females, whose homosexual consortships do not reflect generalized patterns of social affiliation or kinship, we found that adolescent females’ same-sex sexual partners were neither kin, nor were they non-kin individuals with whom adolescent females were closely affiliated outside of a consortship context. Our study furthers the growing database of female homosexual behavior in Japanese macaques and provides additional evidence that homosexual behavior as expressed by adolescent female Japanese macaques is, like heterosexual behavior, sexual in nature. We discuss the relevance of our findings to a broader comparative approach that may shed light upon the development and evolution of human homosexuality. Am. J. Primatol. © 2015 Wiley Periodicals, Inc.
... Consortships can be brief, lasting <1 h, or they can continue for over a week. During same-sex consortships, females solicit each other to mount, and to be mounted, using vocalizations and a variety of postural and facial gestures (Vasey et al., , 2008a. Single mounts between females rarely occur. ...
... For example, like heterosexual behavior, female homosexual behavior is never observed outside of the species' fall-winter mating season and only occurs within the context of temporary, but exclusive, consortships (Fedigan and Gouzoules, 1978;Gouzoules and Goy, 1983;Wolfe, 1984). Similarly, the patterns of courtship behavior exhibited by females are virtually identical across homosexual and heterosexual contexts (Vasey et al., 2008a) and the same is true for patterns of inter-mount behavioral activity during consortships (Vasey et al., 2008b). ...
In this paper, we review research related to female homosexual behavior in Japanese macaque (Macaca fuscata), including our 20-year program of study of this species. Multiple lines of evidence indicate that female homosexual behavior in this species is sexually motivated. In contrast, many sociosexual hypotheses have been tested in relation to female homosexual behavior in Japanese macaques, but none have been supported. Female Japanese macaques sometimes engage in same-sex sexual activity even when motivated opposite-sex alternatives are available. Within this context of mate choice, males compete inter-sexually for opportunities to copulate with females above and beyond any intra-sexual competition that is required. Anecdotal evidence suggests that inter-sexual competition for female sexual partners have been observed in a number of other species, including humans. At present it is unclear whether inter-sexual competition for sexual partners influences patterns of reproduction. Our understanding of sexual selection and the evolution of mating systems may be improved by investigating whether inter-sexual mate competition influences the acquisition and maintenance of reproductive partners in those species in which such interactions occur.
... In contrast with lip smacking and girneys, neither the rocking embrace nor the ventro-ventral embrace (without rocking) between anoestrous adult females have been previously reported in Japanese macaques, although the ventro-ventral embrace occurs between consort pairs (i.e. heterosexual: an adult male and an oestrous female; homosexual: two oestrous females) (Enomoto 1974;Vasey et al. 2008) or between a mother and infant pair (Negayama et al. 1986). Nakagawa et al. (2011) conducted a questionnaire survey of primatologists with one or more year(s) of experience in field research at each study site and found no confirmed instances of ventro-ventral embrace between anoestrous adult female Japanese macaques at three well-known long-term study sites: Arashiyama, Katsuyama, and Takasakiyama. ...
... Judging from behaviours performed immediately before or after the rocking embrace, even the rocking embrace involving oestrous adult females never occurs in a sexual context. In contrast with that observed among the Japanese macaques in Jigokudani (Enomoto 1974) and Arashiyama (Vasey et al. 2008), female-female mounting has rarely been observed in Kinkazan (Nakagawa et al. 2011). Moreover, the rocking embrace has been observed during seasons other than the mating seasons in Kinkazan (N.N. unpub), so it is considered to occur in an asexual context. ...
Recently, research has focused on the effects of the concurrence of multimodal signals and their efficacy and meaning. We observed an unreported behaviour, a ventro-ventral "rocking-embrace" gesture that is always accompanied by lip smacking as the facial expression and sometimes by a girney call, in wild Japanese macaques (Macaca fuscata) living in Kinkazan Island, northern Japan. This study examined the form and contexts of the occurrence of such multimodal signals in order to elucidate its functions. Eighty-eight cases of rocking embrace were recorded during 183 h of observation over 22 days. Adult females were involved in all of the cases. Of the 71 cases between adult females in which behaviours prior to the rocking embrace could be identified, 13 cases were allogrooming interruptions, 11 were aggression, and 42 were approaches, most of which occurred between non-kin grooming partners. The rocking embrace was often followed by allogrooming. This suggests that rocking embraces occur under stressful conditions and may function to reduce tensions. This conclusion is consistent with the contexts and functions of lip smacking and girneys shown in previous studies. In contrast with lip smacking and girneys, neither a rocking embrace nor a ventro-ventral embrace (without rocking) between anoestrous adult females has been previously shown in Japanese macaques. In other macaque species, however, the latter gesture is often observed as an affiliative behaviour that immediately follows conflict; it functions to reconcile or as a greeting when it occurs immediately after an approach. Rocking embraces among the Kinkazan macaques occur in contexts similar to, and have a similar function to, the ancestral gesture of ventro-ventral embracing (which is hidden in Japanese macaques) and the ancestral display of lip smacking (which is still observed in Japanese macaques). The ventro-ventral embrace as a tactile signal might have been hidden since it was made redundant by the visual signal of lip smacking in ancestral macaques.
... (2) 'non-demonstrative' sexual solicitations were directed toward, and received from, females. Non-demonstrative sexual solicitations included following the target and sitting between 5 and 10 m away from it for at least 5 min while glancing at it repeatedly, (3) mounting behaviours received and performed, and (4) non-sexual activities such as resting, foraging, moving, grooming interactions, playful interactions, agonistic interactions (approach/avoidance events and aggressions with or without physical contact) (cf., Enomoto, 1974;Enomoto et al., 1979;Fedigan, 1982;Vasey et al., 2008a). The identities of the non-focal individuals (males or females) involved in these interactions were also recorded, whether they were performers (i.e., partners) or recipients (i.e., targets) of these behaviours. ...
... The fact that as early as two years, juvenile males' sexual mounts were mostly directed to adult females is in agreement with many studies on other species of cercopithecines (cf., Dixson, 2012). Juvenile males mounted more frequently than juvenile females (Prediction No. 3), and had a wider array of mounting partners than juvenile females (Table 4), which provides indicates that mounting is a predominately male-typical behaviour among juvenile Japanese macaques (cf., Baum, 1979), even though adult females in this species mount on a routine basis (Vasey et al., , 2008a. ...
The emergence of conceptive and non-conceptive sexual behaviours in mature individuals can be traced back to immature socio-sexual behavioural patterns. We tested the ‘needing-to-learn hypothesis’ in the development of sexual behaviours in the immature male Japanese macaques of Arashiyama, Japan. This hypothesis holds that juvenility serves to provide young individuals with a period in which to practice adult male-like sexual and socio-sexual behaviours and partner choice. Our cross-sectional focal data on mounting behaviour and partner choice in juvenile males (1–3 years) supported most of our predictions: (1) as they became older and learnt more effective patterns of sexual solicitations, juvenile males performed more demonstrative solicitations and less non-demonstrative solicitations, (2) the frequency of mounts performed by juvenile males increased with age and converged on a frequency of mounts typical of adult males, (3) the frequency of mounts reflecting underachievement (i.e., improperly oriented mounts and single/no foot-clasp mounts) decreased as juvenile males became older, (4) the double foot-clasp mounting posture became gradually more common in juvenile males over time, while other mounting postures became less common and (5) from two to three years old, the frequency of males’ sexual mounts directed to adult females increased. Such timelines of gradual increase in the frequency of effective adult-like behavioural patterns and gradual decrease in the frequency of less effective immature behavioural patterns are consistent with the ‘needing-to-learn hypothesis’ emphasizing the role of age and practice in the progressive acquisition of adult-like sexual behaviour, mounting skills, and partner age choice during male juvenility.
... Several hypotheses have been proposed to explain the evolution and prevalence of same-sex sexual behaviour in human and nonhuman animals 2,8,11,17,18 . Some of these hypotheses are non-adaptive, suggesting that same-sex sexual behaviour is the consequence of mistaken identity 19,20 , the limited availability of individuals of the opposite sex [21][22][23] , the consequences of sexual frustration when individuals are refused by members of the other sex 20 , or the byproduct of selection acting on a separate trait, such as high sexual responsiveness 24 . A recently proposed hypothesis that is attracting much attention states that indiscriminate sexual behaviour (that is, the co-occurrence of different-sex sexual behaviour and same-sex sexual behaviour) is the ancestral condition for sexually reproducing animals and this explains the widespread occurrence of same-sex sexual behaviour in animals 3,16 . ...
Same-sex sexual behaviour has attracted the attention of many scientists working in disparate areas, from sociology and psychology to behavioural and evolutionary biology. Since it does not contribute directly to reproduction, same-sex sexual behaviour is considered an evolutionary conundrum. Here, using phylogenetic analyses, we explore the evolution of same-sex sexual behaviour in mammals. According to currently available data, this behaviour is not randomly distributed across mammal lineages, but tends to be particularly prevalent in some clades, especially primates. Ancestral reconstruction suggests that same-sex sexual behaviour may have evolved multiple times, with its appearance being a recent phenomenon in most mammalian lineages. Our phylogenetically informed analyses testing for associations between same-sex sexual behaviour and other species characteristics suggest that it may play an adaptive role in maintaining social relationships and mitigating conflict.
... Research in female Japanese macaques, gorillas and langurs have disputed the link between SSB and coalitionary behaviour 1,31,50 . In female bonobos (for which there is strong evidence of a reconciliatory function via post-conflict SSB between opponents 24,25 ), the coalitionary support function remains popular 25 but somewhat unresolved 1,[51][52][53][54] . ...
Numerous reports have documented the occurrence of same-sex sociosexual behaviour (SSB) across animal species. However, the distribution of the behaviour within a species needs to be studied to test hypotheses describing its evolution and maintenance, in particular whether the behaviour is heritable and can therefore evolve by natural selection. Here we collected detailed observations across 3 yr of social and mounting behaviour of 236 male semi-wild rhesus macaques, which we combined with a pedigree dating back to 1938, to show that SSB is both repeatable (19.35%) and heritable (6.4%). Demographic factors (age and group structure) explained SSB variation only marginally. Furthermore, we found a positive genetic correlation between same-sex mounter and mountee activities, indicating a common basis to different forms of SSB. Finally, we found no evidence of fitness costs to SSB, but show instead that the behaviour mediated coalitionary partnerships that have been linked to improved reproductive success. Together, our results demonstrate that SSB is frequent in rhesus macaques, can evolve, and is not costly, indicating that SSB may be a common feature of primate reproductive ecology.
... Like masturbation, most observations of SSB were in subadult males. Since subadult males are often unsuccessful in their mating attempts with adult females, SSB may be an evolutionary byproduct, where reproductive sex has led to high sexual responsiveness but subadult males have a lack of reproductive opportunities (Vasey et al., 2008). It is interesting however, that about a third of the SSB we observed among subadult males occurred during a period of time when several males were dispersing out of their group and forming an AMB. ...
Rare behaviors are often missing from published papers, hampering phylogenetic analyses. Here, we report, for the first time, masturbation and same-sex sexual behavior (SSB) in both male and female black-and-white colobus monkeys. We recorded these behaviors during 32 months of observation (1573 h of focal animal sampling) on Colobus vellerosus collected at the Boabeng-Fiema Monkey Sanctuary in Ghana. Males were observed masturbating and involved in SSB more than females. Subadult males were the age-sex class that engaged in both of these behaviors most often and a third of all SSB observed in young males occurred when they were forming an all-male band (AMB), which are temporally transient social groups in this species. Our data support that masturbation in males may be a sexual outlet for individuals that do not have a current sexual partner, while in females it may function in mate attraction by advertising receptivity. SSB may occur as an evolutionary byproduct but given the temporal clustering of observed events in males prior to AMB formation, our data best support the hypothesis that these behaviors facilitate male-male bonding (i.e., act as social glue). Within AMB's, males engage in coalitionary behavior to take over social groups containing females and strong bonds are important for success and later access to females, which could have selected for SSB in C. vellerosus.
... Essas características vantajosas às quais as SMS estão vinculadas podem ser características que tipicamente se manifestam no sexo oposto, derivadas de efeitos pleiotrópicos (i.e., um fenômeno genético em que um único gene influencia as manifestações de várias características) (J. M. Bailey, Gaulin, Agyei, & Gladue, 1994;Bártová & Valentova, 2012;Vasey, Rains, VanderLaan, Duckworth, & Kovacovsky, 2008), ocasionando uma diminuição na dominância extrema dos machos (Werner, 2006), do prazer resultante da atividade sexual (Menezes & Brito, 2007;Vasey 2006), ou ainda, podem decorrer de um antagonismo sexual (Camperio-Ciani, Corna, & Capiluppi, 2004;Iemmola & Camperio-Ciani, 2009). ...
Resumo Sob uma perspectiva evolutiva, as interações sexuais entre indivíduos do mesmo sexo foram por muito tempo consideradas um grande paradoxo. Isso por terem persistido no decorrer das gerações apesar de supostamente não oferecerem benefícios reprodutivos diretos, reduzindo, aparentemente, a aptidão individual. Apesar disso, são comuns em muitas espécies animais. Neste artigo, revisaremos algumas das hipóteses funcionais que tentam resolver esse quebra-cabeça evolutivo. Algumas dessas hipóteses consideram essas interações adaptativas, o que significa que trariam benefícios para os indivíduos. Outras as consideram neutras, derivadas de características realmente vantajosas. Por fim, existem as que consideram essas interações como não-adaptativas e potencialmente prejudiciais aos indivíduos. Ao final, abordaremos uma hipótese revolucionária que, de forma inédita, questiona se as interações sexuais envolvendo exclusivamente indivíduos de sexos diferentes seriam realmente o estado basal do comportamento sexual.
... A common explanation for SSB is the absence of perfect sex discrimination, such that individuals either attempt matings without determining the sex of their partner or discrimination occurs with errors (the "mistaken identity hypothesis;" Bailey and French 2012;Macchiano et al. 2018;Sales et al. 2018). This proximate explanation for SSB has a number of potential ultimate causes that all posit that discrimination carries a cost that maintains some degree of SSB, such as a tradeoff between number of matings and discrimination (Han and Brooks 2015;Logue et al. 2009;Vasey et al. 2008) or a survival, fecundity, or gamete production cost to discrimination (Parker 2014;Lerch and Servedio 2021). Such costs to discrimination can result in a reproductive strategy of indiscriminate mating (i.e., attempting matings without first determining the sex of one's partner). ...
The presence of same-sex sexual behavior across the animal kingdom is often viewed as unexpected. One explanation for its prevalence in some taxa is indiscriminate mating-a strategy wherein an individual does not attempt to determine the sex of its potential partner before attempting copulation. Indiscriminate mating has been argued to be the ancestral mode of sexual reproduction and can also be an optimal strategy given search costs of choosiness. Less attention has been paid to the fact that sex discrimination requires not just the attempt to differentiate between the sexes but also some discernible difference (a signal or cue) that can be detected. To address this, we extend models of mating behavior to consider the coevolution of sex discrimination and sexual signals. We find that under a wide range of parameters, including some with relatively minor costs, indiscriminate mating and the absence of sexual signals will be an evolutionary end point. Furthermore, the absence of both sex discrimination and sexual signals is always evolutionarily stable. These results suggest that an observable difference between the sexes likely arose as a by-product of the evolution of different sexes, allowing discrimination to evolve.
... The data collected daily for each female group member (aged 3 and above) included: (1) an estimated intensity of fertility cues, ranked from 1 to 5, and based on non-behavioral cues, such as redness of the facial and genital skin, vaginal secretion, and genital swelling and odor, namely, 1: no cues, 2: low redness of the facial and genital skin, 3: mild redness of the facial and genital skin, and slight genital swelling, 4: intense redness of the facial and genital skin, mild genital swelling, slight vaginal secretion, and slight genital odor, 5: intense redness of the facial and genital skin, high genital swelling, strong vaginal secretion, and strong genital odor; A previous study indicates that daily changes in these morphological and physiological features correlate with the timing of the likelihood of fertile period in female Japanese macaques (Fujita et al., 2004); (2) heterosexual solicitations received, such as "bird-dogging" (i.e., a strut/ approach followed by frozen stance with lip quivering/staring and tail up; Fedigan, 1982); (3) heterosexual solicitations performed, such as specific body postures (hindquarter presentations and inclined-back presentations), body movements and gestures (ground smacking, hands-on-hindquarters solicitations, and body spasms), and sexual vocalizations; (4) homosexual solicitations received and performed (same as heterosexual solicitations, and only collected during the 2001, 2003, 2010-11 and 2011-12 mating seasons); (5) heterosexual and homosexual mounting behaviors received and performed; and (6) heterosexual and homosexual consortships, defined as a temporary, but exclusive, sexual association between two (opposite-sex or same-sex, respectively) individuals engaged in series-mounting (i.e., two or more mounts within a 1-min period; Table 2; cf. Enomoto et al., 1979;Vasey et al., 2008a;S. Tamada, personal communication). ...
We assessed the effect of a progestin-based contraceptive treatment (chlormadinone acetate) on female heterosexual and homosexual behaviors in a free-ranging group of Japanese macaques (Macaca fuscata) living at Arashiyama-Kyoto, Central Japan. The data included estimated intensity of fertility cues, sexual solicitations and mounting behaviors collected daily during 17 consecutive mating seasons (1995-2012) from 159 females. Females that were on contraception: (1) exhibited less intense cues of putative fertility and for shorter periods; (2) were solicited by fewer males, and those males that did solicit them did so less often (i.e., lower heterosexual attractivity); (3) solicited fewer males and when they did perform sexual solicitations they did so less often (i.e., lower heterosexual proceptivity); (4) engaged in shorter heterosexual consortships with fewer male partners (i.e., lower heterosexual receptivity), compared with females that were not on contraception. In contrast, contraceptive treatment had no significant effect on the prevalence, occurrence, frequency, or duration of female homosexual behaviors. Even though heterosexual and homosexual behaviors can both be considered sexual in character and under hormonal control, our results suggested they are, to some extent, dissociable. Because females engaging in homosexual interactions showed less intense cues of putative fertility than those engaging in heterosexual interactions, regardless of contraceptive treatment, we argued that the hormonal threshold required for the expression of heterosexual behavior by females was associated with elevated sex hormones levels compared to homosexual behavior. We discussed the hormonal correlates of sexual behavior and partner preferences in Japanese macaques.
... The data collected daily for each female group member (aged 3 and above) included: (1) an estimated intensity of fertility cues, ranked from 1 to 5, and based on non-behavioral cues, such as redness of the facial and genital skin, vaginal secretion, and genital swelling and odor, namely, 1: no cues, 2: low redness of the facial and genital skin, 3: mild redness of the facial and genital skin, and slight genital swelling, 4: intense redness of the facial and genital skin, mild genital swelling, slight vaginal secretion, and slight genital odor, 5: intense redness of the facial and genital skin, high genital swelling, strong vaginal secretion, and strong genital odor; A previous study indicates that daily changes in these morphological and physiological features correlate with the timing of the likelihood of fertile period in female Japanese macaques (Fujita et al., 2004); (2) heterosexual solicitations received, such as "bird-dogging" (i.e., a strut/ approach followed by frozen stance with lip quivering/staring and tail up; Fedigan, 1982); (3) heterosexual solicitations performed, such as specific body postures (hindquarter presentations and inclined-back presentations), body movements and gestures (ground smacking, hands-on-hindquarters solicitations, and body spasms), and sexual vocalizations; (4) homosexual solicitations received and performed (same as heterosexual solicitations, and only collected during the 2001, 2003, 2010-11 and 2011-12 mating seasons); (5) heterosexual and homosexual mounting behaviors received and performed; and (6) heterosexual and homosexual consortships, defined as a temporary, but exclusive, sexual association between two (opposite-sex or same-sex, respectively) individuals engaged in series-mounting (i.e., two or more mounts within a 1-min period; Table 2; cf. Enomoto et al., 1979;Vasey et al., 2008a;S. Tamada, personal communication). ...
We assessed the effect of a progestin-based contraceptive treatment (chlormadinone acetate) on female heterosexual and homosexual behaviors in a free-ranging group of Japanese macaques (Macaca fuscata) living at Arashiyama-Kyoto, Central Japan. The data included estimated intensity of fertility cues, sexual solicitations and mounting behaviors collected daily during 17 consecutive mating seasons (1995-2012) from 159 females. Females that were on contraception: (1) exhibited less intense cues of putative fertility and for shorter periods; (2) were solicited by fewer males, and those males that did solicit them did so less often (i.e., lower heterosexual attractivity); (3) solicited fewer males and when they did perform sexual solicitations they did so less often (i.e., lower heterosexual proceptivity); (4) engaged in shorter heterosexual consortships with fewer male partners (i.e., lower heterosexual receptivity), compared with females that were not on contraception. In contrast, contraceptive treatment had no significant effect on the prevalence, occurrence, frequency, or duration of female homosexual behaviors. Even though heterosexual and homosexual behaviors can both be considered sexual in character and under hormonal control, our results suggested they are, to some extent, dissociable. Because females engaging in homosexual interactions showed less intense cues of putative fertility than those engaging in heterosexual interactions, regardless of contraceptive treatment, we argued that the hormonal threshold required for the expression of heterosexual behavior by females was associated with elevated sex hormones levels compared to homosexual behavior. We discussed the hormonal correlates of sexual behavior and partner preferences in Japanese macaques.
... It is well known that net costs and benefits of sexual interactions may depend on the relative frequencies of male-female and malemale approaches (Harshman & Zera 2007;Maklakov & Bonduriansky 2009), and we note that further research is needed to quantify benefits and costs of sexual activities in the context in which parasitic wasps evolve. As suggested by Vasey et al. (2008) and as extensively analyzed by Bailey & Zuk (2009) for other species, we cannot exclude the possibility that P. concolor same-sex sexual interaction arises as a by-product of selection on a separate trait, such as high sexual responsiveness. ...
Costs of sexual interactions play a key role in life-history evolution. Although the costs of reproduction have been investigated in both sexes of many insects, the costs of same-sex interactions have been examined in few species. In parasitic wasps, very little has been reported about the longevity costs of heterosexual interactions, and nothing is known about longevity costs of same-sex interactions. In this study, the effects of heterosexual and homosexual activities on longevity were evaluated in Psyttalia concolor (Hymenoptera: Braconidae), a synovigenic koinobiont larval-pupal endoparasitoid of tephritid flies. When compared with individually housed virgin wasps, male longevity was strongly reduced both in males kept with females, and in males kept with other males. When females were kept with males, their longevity was reduced compared with the virgin females and females kept with other females. Overall, the costs of male–female interactions were considerable in both sexes of P. concolor, while same-sex activities were found to be costly only among males, suggesting that they may have implications for the evolution of the P. concolor mating system.
... Under these conditions, a previous courting experience may allow P. concolor males to refine their courtship performances and to perform higher courtship intensities in the successive female's approaches, as already suggested by Dukas (2005Dukas ( , 2010 for D. melanogaster. According to Vasey et al. (2008), and as extensively analyzed by Bailey and Zuk (2009) for other species, the possibility that P. concolor same-sex sexual interaction arises as a by-product of selection on a separate trait, such as high sexual responsiveness, cannot be excluded. Further research is required to clarify this point and to evaluate if P. concolor wasps that have already mated or not display different traits in same-sex sexual interactions. ...
Abstract The role of male-male courtship in parasitic Hymenoptera is poorly known. A laboratory study was conducted to assess if Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae) male courtship can be affected by a previous experience in courting young conspecifics of both sexes. Two experiments were performed to evaluate the effect of experience in courting young wasps on both male courtship and male-male competition behavior. Results showed that a courting experience on both sexes can modify some sexual traits in a P. concolor male, without affecting its success in mating. When approaching virgin females, a P. concolor male that had a previous courtship experience with young wasps of either sex showed shorter latency times, more wing fanning, and longer courtship durations with respect to the control male. The hypothesis that a previous courting experience may allow a P. concolor male to refine its courtship behavior and to enhance courtship intensity in subsequent encounters with females was discussed.
... Same-sex courtship and mating behaviors are well known in birds and widespread among insects and mammal species (e.g., Dagg 1984;Vasey 1995;Mac-Farlane et al. 2007;Vasey et al. 2008;Bailey & Zuk 2009). In birds, the proximate and ultimate bases for such behaviors may differ for males and females of the same species (MacFarlane et al. 2007). ...
More than 50 yr ago, field studies recorded the same-sex pairs (and trios) of penguins displaying to each other during the mating season, using behavior patterns typical of heterosexual mating displays. Such observations led to a hypothesis that due to a lack of sex recognition pairing occurs at random with respect to sex, an idea countered by the argument that sex recognition is highly accurate. No quantification of same-sex mating displays has tested the frequency of such displays in penguins or tested the hypothesis of random display partners with respect to sex. During their mating season, we studied displaying and paired king penguins, Apenodytes patagonicus, at Kerguelen Island and sexed them using a DNA marker, to quantify any occurrence of this behavior. Indeed, same-sex courtship displays were common (28.3% of 53 displaying pairs), the great majority of which were between males. Some homosexually displaying males eventually paired with females, but such males were significantly slower in heterosexual pairing than males that did not display homosexually. In two extraordinary cases, same-sex pairs learned each other’s calls, an essential step in the pairing process. The frequency of such pairs was much lower than among displaying couples, significantly so for males. Finally, the frequency of homosexually displaying pairs was significantly lower than expected from random assortment of displaying birds, for both males and females. We examined possible explanations for same-sex display and its biological significance. A population sex-ratio bias in favor of males and high concentration of male sex hormones may help to explain non-reproductive homosexually displaying pairs.
... First, these interactions mirror male-female sexual behavior in many aspects of their expression. For example, the courtship behavior that females exhibit during homosexual consortships is virtually indistinguishable from that which occurs during heterosexual consortships (Vasey, Rains, VanderLaan, Duckworth, & Kovacovsky, 2008). Similarly, female-female mounting across the ovarian cycle parallels the pattern found for male-female mounting (O'Neill, Fedigan, & Ziegler, 2004). ...
In certain Japanese macaque (Macaca fuscata) populations, females routinely engage in same-sex courtship, mounting, and consortship activity. Drawing on behavioral, biogeographic, and genetic research, we suggest that female homosexual behavior may be associated with genetically distinct free-ranging populations of Japanese macaques. In addition, we briefly discuss the implications of this research for the evolution of female homosexual behavior in this species.
In primates, same-sex and immature sexual behaviour is widespread and can include mounting and genital presentation. These patterns can be observed in multiple social contexts and across all ages, and can serve functions such as appeasement, reconciliation, practice and dominance assertion. In this study, we investigated same-sex and immature sexual behaviour in a group of robust capuchins (Sapajus nigritus) living in an Atlantic forest fragment and urban areas. We predicted that in order to practice sex, sexual behaviour in same-sex dyads and/or dyads that included immatures would resemble the adult heterosexual repertoire for solicitation through courtship displays, mounts and post-copulatory display. We also predicted that immature individuals would engage more frequently than adults in sexual interactions, in order to practice sex. We conducted all-occurrence observations of sexual behaviour in the study group (28 individuals: four adult males, one sub-adult male, eight adult females, eight juveniles and seven infants) from September 2016 to August 2017. Sexual interactions that included at least one immature individual in the dyad and/or occurred between individuals of the same sex were infrequent (N = 52, 0.13 interactions/hour), but much more frequent than heterosexual sexual interactions between adults in the group (N = 4, 0.01 interactions/hour). The same-sex and immature sexual repertoire resembled the described heterosexual patterns for the same species from the literature. Individuals displayed solicitation behaviours in “one-way courtship”, usually followed by a two-way courtship and then mounts, but post-copulatory behaviour was never observed. Except for the alpha male, all age-sex classes engaged in sexual interactions in same-sex dyads or in dyads that included immature individuals. We found no difference in frequency of participation across age classes, however, male-male dyads engaged more frequently in sexual interactions and may be practicing sex and courtship behaviours. Mounts are unlikely to be a form of dominance assertion as the alpha male did not participate, subordinate adult males did not engage in mounts with other subordinate adult males, juveniles mounted adult males and vice versa, and there were mount switches (taking turns as mounter and mountee) regardless of the initial mounter’s age. Contrary to the post-conflict context observed in Cebus, most mounts in this study were preceded by play. Combining our study with additional evidence for the genus, same-sex mounts and mounts that include immatures seem to occur most commonly in affiliative contexts within Sapajus. Sexual behaviour functions in Sapajus require additional investigation, especially among adult males and juveniles of both sexes.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
Previous research on Japanese macaques has shown that female-to-male mounting (FMM) is performed by some females as an exaggerated form of sexual solicitation that may occur in the context of high female competition for male mates. This supernormal courtship behavior functions to prompt subsequent male-to-female mounting. In this report, we focused on the male consort partners' responses to FMM. We studied a free-ranging population of Japanese macaques at Arashiyama, Japan, in which FMM is frequent and prevalent. We analyzed 240 consortships involving 31 females and 19 males. We tested three hypotheses regarding male's tolerance, solicitation, and use of FMM. First, we found that FMM was tolerated by male mountees who were no more likely to aggress their female partners during a short time window around a FMM than they were during the rest of the consortship period. Second, we showed that FMM could be triggered by male recipients, via explicit male-to-female sexual solicitations. Third, we found that some males may utilize FMM in a quest for their own sexual stimulation, which sometimes culminated in masturbation by the male during FMM. Our findings indicate that male partners facilitate the expression of FMM both passively (via their tolerance) and actively (via their solicitation). In addition, FMM appears to enhance the sexual arousal of male partners during consortships. We argued that, for females to have expanded their repertoire of sexual solicitations by adopting FMM, male mates must have played a role in the evolutionary origins and maintenance of this nonconceptive but intense and powerful female mating tactic.
It has been hypothesized that same-sex mounts can reflect the hierarchical relationship in a mounting dyad and it is widely deemed that mounting and being mounted are demonstrations of dominant and subordinate status, respectively. In this research, we aimed to test whether same-sex mounts function as dominance assertion in male golden snub-nosed monkeys (Rhinopithecus roxellana). We investigated this behavior in eight-individuals, captive all-male unit (AMU) in Shanghai wild animal park, China. Behavioral observations were conducted with a total of 1,855 mounts recorded from November, 2014 to June, 2015, during which the alpha male was replaced in the beginning of April. In support to the dominance assertion hypothesis, we found that during the entire study period the higher-ranking male was more likely to be the mounter than the lower-ranking one, except the mounts that happened among juveniles in peaceful and playful social contexts. Our study indicates that the hierarchical relationship of a mounting dyad can be influenced by the age-class of the participants and the social context where mounting occurs. We suggest that same-sex mounts might have different functions in different age groups and be multifunctional in a species.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
We documented nine male homosexual consortships within three different male-male dyads in a free-ranging all-male group of Japanese macaques (Macaca fuscata), at Minoo, Japan. A total of 63 male-male mounts were observed during these consortships. Male homosexual interactions shared most of the behavioral components that have been reported to characterize heterosexual and female homosexual consortships in this species. Convergent behavioral data, including analysis of male-male solicitations, mounting postures, body orientations, inter-mount activities, and third-party male intrusions supported the conclusion that male-male consortships are a sexual phenomenon. We discussed a series of proximate and ultimate hypotheses that purport to account for the occurrence of male homosexual behavior in all-male groups of primates, including humans. This first report of male homosexual interactions in an all-male group of Japanese macaques contributes to the growing database used to provide insights into the developmental processes, causal mechanisms, adaptive significance, and phylogenetic pathways of same-sex sexual behavior.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and to Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology. His research explores the determinants of behavioural innovations and traditions, and the evolution of non-conceptive sexuality, including the motivational mechanisms underlying female-to-male mounting in Arashiyama Japanese macaques.. His research focuses on the development and evolution of non-conceptive sexuality from a cross-species and cross-cultural perspective. He has conducted research on sexual behaviour in free-ranging Japanese macaques at Arashiyama and on the captive subgroup in Montreal. C SBEA Cover illustration: heterosexual consortship between Momo-61-72-80-95 (male) and Blanche-59-64-75-82 (female) at Arashiyama, October 2009. Photo by Noëlle Gunst.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
We studied the development of sexual behaviors in female Japanese macaques (Macaca fuscata) living at Arashiyama, Japan, in a group where adult females routinely exhibit sexual interactions with both males and females. Our cross-sectional data on juvenile, adolescent, and adult females supported most of our predictions related to the learning hypothesis, which holds that adolescence serves to provide females with a period in which to practice adult female-like sexual behavioral patterns, including sexual solicitations, sexual mounts, and spatio-temporal coordination during consortships. We found evidence for a gradual acquisition of adult-like behavioral patterns (e.g., more frequent solicitations with body contact, more frequent complete mounts, more diverse solicitation patterns and complete mounting postures, and longer consortships involving prolonged inter-mount grasping behavior between partners), and a gradual disappearance of less effective immature behavioral patterns (e.g., less frequent non-contact solicitations, ambiguous mounting initiations, and incomplete mounts). We distinguished between three major categories of sexual behavioral patterns based on their speed of development, ranging from fast (e.g., diversity in mounting postures and genital stimulation during mounting) to slow (e.g., contact solicitations and grasping behavior between consortship partners), with some being intermediate (e.g., range of solicitation patterns and expression of complete mounts). This study showed that the emergence of both conceptive and non-conceptive adult sexual behaviors can be traced back to immature behavioral patterns in adolescent female Japanese macaques, with a major threshold occurring at the age of 4 years. © 2014 Wiley Periodicals, Inc. Dev Psychobiol.
Homosexuality is an evolutionary paradox in search of a resolution, not a medical condition in search of a cure. Homosexual behaviour is common among social animals, and is mainly expressed within the context of a bisexual sexual orientation. Exclusive homosexuality is less common, but not unique to humans. The author invites the reader to embark on a journey through the evolutionary, biological, psychological and sociological aspects of homosexuality, seeking an understanding of both the proximate and evolutionary causes of homosexual behaviour and orientation in humans, other mammals and birds. The book also provides a synthesis of what we know about homosexuality into a biosocial model that links recent advances in reproductive skew theory and various selection mechanisms to produce a comprehensive framework that will be useful for anyone teaching or planning future research in this field.
The Arashiyama group of Japanese macaques holds a distinguished place in primatology as one of the longest continuously studied non-human primate populations in the world. The resulting long-term data provide a unique resource for researchers, allowing them to move beyond cross-sectional studies to tackle larger issues involving individual, matrilineal and group histories. This book presents an overview of the scope and magnitude of research topics and management efforts that have been conducted on this population for several decades, covering not only the original troop living around Kyoto, Japan, but also the two subgroups that were translocated to Texas, USA and Montreal, Canada. The chapters encompass topics including life history, sexual, social and cultural behaviour and ecology, giving an insight into the range of current primatological research. The contributors underscore the historic value of the Arashiyama macaques and showcase new and significant research findings that highlight their continuing importance to primatology.
Same-sex sexual behavior has been extensively documented in non-human animals. Here we review the contexts in which it has been studied, focusing on case studies that have tested both adaptive and non-adaptive explanations for the persistence of same-sex sexual behavior. Researchers have begun to make headway unraveling possible evolutionary origins of these behaviors and reasons for their maintenance in populations, and we advocate expanding these approaches to examine their role as agents of evolutionary change. Future research employing theoretical, comparative and experimental approaches could provide a greater understanding not only of how selection might have driven the evolution of same-sex sexual behaviors but also ways in which such behaviors act as selective forces that shape social, morphological and behavioral evolution.
Age preferences expressed by homosexuals and heterosexuals in 783 singles ads were compared. In line with earlier cross-cultural findings, heterosexual women at all ages tend to prefer men from their own age to several years older. Heterosexual men change with age; young men show an interest in both older and younger women, but older men express progressively stronger interest in women younger than themselves. Homosexual men's preferences were very similar to those of heterosexual men and homosexual women showed a pattern somewhat between that of heterosexual women and men. Results combine with previous literature to suggest that homosexual choice is not a simple and general reversal of heterosexual roles, and fit with an emerging view that sexual behavior is controlled by a number of independently evolved psychological mechanisms. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Sexual selection theory provides a powerful model for the analysis of psychological sex differences. This research examined (a) tests of several sex differences in mating psychology predicted from sexual selection theory, (b) broad developmental hypotheses about sex differences in mating psychology--through the relationship of mating psychology to sexual orientation, and (c) the structure of within-sex differences in mating psychology. Scales measuring aspects of mating psychology were administered to heterosexual and homosexual Ss of both sexes. The structure of scale intercorrelations was similar across groups. All scales yielded sex differences consistent with sexual selection theory. Homosexual Ss generally obtained scores similar to those of same-sex heterosexual Ss, though several scales were significantly related to sexual orientation. Findings constrain hypotheses concerning the origins of sex differences.
The sexual age preferences of 192 adults (equal groups of heterosexual men, heterosexual women, homosexual men, and homosexual women) were examined. Participants rated the sexual attractiveness of pictures of 15 male and 15 female faces arranged into five apparent average age categories ranging from 18 to 60 years. It was predicted that homosexual and heterosexual men would prefer younger partners of their preferred sex than would homosexual and heterosexual women and that age preference would not vary with participant age. Both predictions were supported, although homosexual women preferred older partners than expected. Results suggest that age and sex preferences develop independently.
Whether animals ever exhibit a preference for same-sex sexual partners is a subject of debate. Japanese macaques represent excellent models for examining issues related to sexual preference in animals because females, in certain populations, routinely engage in both heterosexual and homosexual behavior over the course of their life spans. Multiple lines of evidence indicate that female homosexual behavior in Japanese macaques is a sexual behavior, not a sociosexual one. Additional evidence indicates that female Japanese macaques do not engage in homosexual behavior simply because acceptable male mates are unavailable or unmotivated to copulate. Patterns of sexual partner choice by female Japanese macaques that are the focus of intersexual competition indicate that females of this species choose same-sex sexual partners even when they are simultaneously presented with a motivated, opposite-sex alternative. Thus, in some populations of Japanese macaques, females prefer certain same-sex sexual partners relative to certain male mates, and vice versa. Taken together, this evidence suggests that female Japanese macaques are best characterized as bisexual in orientation, not preferentially homosexual or preferentially heterosexual.
Studies in evolutionary psychology and sexual selection theory show that heterosexual men prefer younger mating partners than heterosexual women in order to ensure reproductive success. However, previous research has generally not examined differences in mating preferences as a function of sexual orientation or the type of relationship sought in naturalistic settings. Given that homosexual men seek partners for reasons other than procreation, they may exhibit different mating preferences than their heterosexual counterparts. Moreover, mating preferences may show important differences depending on whether an individual is seeking a long-term versus a short-term relationship. The purpose of the present study was to examine these issues by comparing partner preferences in terms of age and relationship type between homosexual and heterosexual men placing internet personal advertisements. Participants included 439 homosexual and 365 heterosexual men who placed internet ads in the U.S. or Canada. Ads were coded for the participant's age, relationship type (longer-term or short-term sexual encounter) sought, and partner age preferences. Significantly more homosexual than heterosexual men sought sexual encounters, although men (regardless of sexual orientation) seeking sexual encounters preferred a significantly wider age range of partners than men seeking longer-term relationships. These findings suggest that partner preferences are independent of evolutionary drives to procreate, since both types of men preferred similar ages in their partners. In addition, they highlight the importance of examining relationship type in evolutionary studies of mating preferences, as men's partner preferences show important differences depending upon the type of relationship sought.
Homosexual behavior is defined as genital contact, genital manipulation or both between same-sex individuals. Available data
indicate that this behavior is phylogenetically widespread among the anthropoid primates, but totally absent among prosimians.
The majority of the 33 species that demonstrate homosexual behavior do so rarefy, but for a substantial number (N =12) it appears to be a more common pattern under free-ranging conditions. I summarize data on homosexual behavior as it relates
to form, living condition, age, sex, social organization, and ecological context, and discuss hormonal, demographic, and sociosexual
theories for primate homosexual behavior. Among adult primates, the behavior is not the product of abnormal excesses or deficiencies
in androgens. Prenatal excesses of androgens may have some effect on the expression of female homosexual behavior, but these
effects might vary over the life span, and data are equivocal at present. Demographic processes that result in skewed sex
ratios can favor the expression of homosexual behavior in a population, which causes intraspecific variation. I examine several
sociosexual explanations, including (a) proceptivity enhancement, (b) receptivity reduction, (c) dominance assertion, (d)
practice for heterosexual copulation, (e) tension regulation, (f) reconciliation, and (g) alliance formation. An evolutionary
scenario highlights the transformations this behavior underwent during the evolution of the anthropoid primates. I suggest
exaptation as a theoretical framework for interpreting homosexual behavior and conclude that future consideration of sexual
selection among primates should address homosexual components of this process.
Biological Exuberance by Bruce Bagemihl. textlessPtextgreaterA Publishers Weekly Best BookOne of the New York Public... Bonus Publisher Materials: Excerpt, Praise, Author Biography, Awards
This chapter discusses the social structure of Japanese monkeys, renunciation of the natal troop, approach to and joining of the troop by Hanarezam, and longevity and mortality of male Japanese monkeys. The multimale and multifemale troop of Japanese monkeys at Takasakiyama is controlled by a group of leader males, while females and infants occupy the central part of the troop under the protection of leader males. Most male Japanese monkeys desert their natal troops and spend much of their long life as wanderers. Although, some male Japanese monkeys, which disappear, must die, comparisons with the survival curves of females and some individually known cases indicate that many others, which leave the troop survive. It is uncertain, whether many males died in or out of the troop, and the critical reason for the difference between the mortalities of the sexes is not known, it is likely that the hanarezaru are less able to find food and encounter many more dangers. The study presents that observing the life history of Japanese monkeys from the long-range viewpoint, the rank order, the social role, and social hierarchy regulate social friction among spontaneously coexisting animals.
Observations of a captive colony of Japanese macaques (Macaca fuscata) were carried out with the goal of documenting (1) competition between males and females for female sexual partners and (2) choice of same-sex sexual partners by females, despite the presence of motivated, opposite-sex alternatives. Data were collected during 21 homosexual consorts hips involving 14 females living in a mixed-sex group of 37 individuals. Intersexual competition for female sexual partners was manifested when a sexually motivated male and female (competitors) simultaneously sought exclusive access to the same infertile or post-conception female (focus of competition). This occurred during male intrusions on female homosexual consortships and counter-challenges by female competitors against intruding males. Inter-sexual competition for female sexual partners took the form of approaches and solicitations directed at the focus of competition, as well as displacements and aggression directed at one's competitor. Females did not acquire alloparental care for their immature offspring from their same-sex consort partners. Thus, female competitors appeared to engaged in potentially risky competition for same-sex sexual partners in the absence of any obvious reproductive benefit (e.g. insemination or alloparental care). Following these interactions, females which were foci of competition chose to mount with the female competitors significantly more often than not.
The behavior of male-female (M-F) and female-female (F-F) paired Western Gulls (Larus occidentalis) before egg laying was examined on Santa Barbara Island, California to test the hypothesis that one female in a F-F pair may assume a male role. In M-F pairs, no behaviors were performed exclusively by either sex, although males Mounted more often, females Head-tossed more often and males acted more aggressively toward intruders. Within F-F pairs, neither partner consistently showed masculine behavior. In a comparison of behavior toward intruders, both members of F-F pairs resembled the female in M-F pairs, and were generally significantly different from males. We therefore reject the hypothesis that female-female pairing is the result of either the adoption of a "male" behavioral role by one or both partners, or an extreme "female" role by one member.
Female mounting behavior was studied in a troop of Japanese macaques during one breeding season. Of 79 sexually active females, mounting behavior during consortships was shown by 50 females; 13 only with males, 20 with both males and females, and 17 only with females. Several factors associated with reproductive state influenced the expression of mounting activity. Recency of parturition influenced the mounting by females regardless of the type of partner. Females that had not given birth the previous spring (four to six months prior to the period of observation) were more likely both to mount partners and to produce an infant the following spring. These findings suggest the existence of a common factor, perhaps associated with lactation, inhibitory both to expression of mounting and to female fertility. Additionally, females that mounted were more likely to do so in consortships that followed than in those that preceded conception. This last finding suggests that, in this social context, the endocrine conditions of early pregnancy facilitated mounting to a greater extent than those associated with the cyclic ovary. Separate statistical analyses examined possible influences of age, dominance rank, and kinship on the likelihoods of mounting and being mounted. None of these factors influenced female mounting. Results suggest that the expression of mounting by females was more influenced by reproductive state than by social characteristics of the partner.
It is suggested that female-female mounting, common in domestic cattle and various other mammals during oestrus, may have a function in attracting the male and ensuring a mating. As such it could serve as a potent alternative to more direct forms of solicitation. Especially where intra-male competition (sexual selection) is intense, behaviour characteristic of rival males (e.g. mounting, threat displays, etc.) should act as a powerful attractor of the dominant herd bull, thus having a dual advantage to the female, and explaining the origin of the behaviour. Anoestrus mounting of an oestrus mountee can be explained by kin selection and/or reciprocal altruism.
For various reasons, penile and clitoral prepuces have been amputated from children in certain human societies for thousands of years. Although the justifications for male and female circumcision have changed over the last several thousand years, the practice of circumcision has not been examined from the perspective of primate evolution. Why do primates have a prepuce, and what function does it have? The comparative anatomy between human and non-human primates will be reviewed with a specific focus on the sensory innervation of the prepuce and glans.
A practicing statistician looks at the multiple comparison controversy and related issues through the eyes of the users. The concept of consistency is introduced and discussed in relation to five of the more common multiple comparison procedures. All of the procedures are found to be inconsistent except the simplest procedure, the unrestricted least significant difference (LSD) procedure (or multiple t test). For this and other reasons the unrestricted LSD procedure is recommended for general use, with the proviso that it should be viewed as a hypothesis generator rather than as a method for simultaneous hypothesis generation and testing. The implications for Scheffé's test for general contrasts are also discussed, and a new recommendation is made.
In this study, we examined whether female Japanese macaques (Macaca fuscata) exhibited male-typical patterns of inter-mount social behaviour during homosexual consortships. Data were collected on heterosexual and homosexual consortships from a population of free-ranging Japanese macaques in Arashiyama, Japan. Inter-mount intervals were defined as the period between two consecutive mounts. A total of 3374 heterosexual inter-mount intervals and 1412 homosexual inter-mount intervals were analysed. We examined nine different categories of inter-mount behaviour. Sex differences between heterosexually consorting males and females existed for three of the inter-mount behaviours we examined (i.e. ventral-to-dorsal orientation, aggression directed toward third party individuals, tree-shaking displays). The subordinate female partners in homosexually consorting pairs exhibited some sex-atypical inter-mount behaviours. This sex-atypicality did not appear to reflect generalized developmental canalization in the direction of a male-typical suite of behaviours. Rather, the observed behavioural sex-atypicality could be best explained in terms of the unique alliance-related dynamics that characterized homosexual consortships in Japanese macaques.
This paper reports a systematic pattern of homosexual incest avoidance among females in a captive group of Japanese macaques (Macaca fuscata) culled from the Arashiyama-West troop known for its high rates of female homosexuality. The study group included three matrilines and two generations. Between eight and 11 females were sexually active over four consecutive mating seasons, and all engaged in both heterosexual and homosexual activity. While all females performed homosexual acts with almost all possible non-kin partners, they systematically avoided homosexual interactions with their mother, daughters, and sisters. This pattern could not be explained either in terms of kin not being simultaneously in estrus, kin avoiding affiliative interactions in general, or non-kin utilizing the tension-reducing effect of estrus to affiliate exclusively with each other. In contrast to homosexual females, heterosexual pairs of relatives (brother-sister, mother-son) were sometimes incestuous. Assuming that female homosexuality expresses the reproductive strategy of females unconstrained by male influence, the present results point to the strong tendency of females to avoid incest and suggest that males are primarily responsible for the reported exceptions to incest avoidance.
The goal of the work reported here was to determine whether female Japanese macaques (Macaca fuscata) participated in same-sex mounting interactions during homosexual consortships to communicate about asymmetries in their dominance relationships and to reduce aggression. Focal data were collected during 21 homosexual consortships involving 14 females living in a captive, mixed-sex group of 37 individuals. We identified eight types of mounts, one solicitation used specifically to request to mount (hands-on-hindquarters solicitation), two solicitations used specifically to request to be mounted (hindquarter and back presentations), and one behavior employed to facilitate mounts-in-progress (clasping). We tested whether dominant consort partners (1) mounted more and (2) requested to mount more than their subordinate partners and whether subordinate consort partners (1) requested to be mounted more and (2) facilitated mounts-in-progress more than their dominant partners. Finally, we examined whether mounting was temporally linked to the onset of aggressive interactions between consort partners and whether it functioned to defuse incipient aggression. None of these predictions was supported. All types of mounts, mount solicitations, and clasping occurred bi-directionally within consort dyads. Mutual sexual attraction and gratification provided the proximate motivation for these mounting interactions and, in turn, for the formation and maintenance of their homosexual consortships.
In this paper we present the results of a behavioral experiment conducted to test whether homosexual consortships and sexual
solicitations among female Japanese macaques (Macaca fuscata) increase in the context of operational sex ratios that are heavily skewed towards females. The study involved a baseline
period of observation on an intact social group which had a female-biased sex ratio typical of this species. During the experimental
period which followed, we created a sub-group with an operational sex ratio that was heavily skewed towards females. Compared
to the baseline period, females solicited significantly more same-sex individuals for sex and formed significantly more homosexual
consortships during the experimental period of the study. Females did not appear to engage in homosexual activity during the
study's experimental period simply because they lacked heterosexual alternatives. Instead, we suggest that an abundance of
certain types of preferred, same-sex sexual partners and/or a scarcity of opposite-sex sexual competitors best account for
the increased levels of female homosexual behavior observed at this time.
For various reasons, penile and clitoral prepuces have been amputated from children in certain human societies for thousands
of years. Although the justifications for male and female circumcision have changed over the last several thousand years,
the practice of circumcision has not been examined from the perspective of primate evolution. Why do primates have a prepuce,
and what function does it have? The comparative anatomy between human and non-human primates will be reviewed with a specific
focus on the sensory innervation of the prepuce and glans.
The purposes of this study were to assess whether homosexual behaviour promotes alliance formation between sexual partners and whether individuals engage in homosexual behaviour to form alliances. Data were collected during pre- and post-consortship baseline periods and during 21 of 28 different homosexual consortships observed ad libitum. These consortships involved 14 female Japanese macaques,Macaca fuscata, living in a captive, bisexual group of 37 individuals. Non-kin females intervened for each other significantly more when in homosexual consortships than during the baseline periods. Consort partners did not intervene for other sexually mature, non-kin females in this manner. Interventions were not performed as sexual solicitations. Subordinate consort partners were equally likely to receive alliance support against dominant and subordinate targets, and they routinely received support against targets with whom they had ambiguous dominance relationships. Compared to the baseline periods, subordinate partners directed more agonistic behaviour to other group members, who, in turn, avoided agonistic interactions with these females. Some consorting females, especially subordinate partners, temporarily increased in dominance upon receiving support against dominant targets, or targets with whom they shared an ambiguous dominance relationship. Absence of preference for high-ranking consort partners, coupled with the bi-directional flow of most affiliation within consortships, suggested that choice of same-sex partners was principally based on mutual sexual attraction and not on their potential utility as allies. These data suggest that homosexual behaviour promotes alliance formation between sexual partners, but that individuals do not engage in homosexual behaviour for the express purpose of forming alliances.
Although nepotism has been evidenced in various areas of primate behaviour, relatively little is known on how it varies with degree of relatedness (r). For example, nepotism might decrease proportionally and asymptotically with relatedness, or it might decrease up to a certain relatedness threshold, beyond which it plummets. This issue was investigated by analysing one type of beneficent behaviours, agonistic support (third-party interventions in conflicts), among laboratory-housed female Japanese macaques, Macaca fuscata. In previous experiments, mothers and sisters were tested in situations in which they could help their daughters and younger sisters to outrank peers, which they did successfully. In the present experiments, grandmothers and aunts were tested using similar protocols. In the presence of their grandmother, granddaughters outranked all dominant peers, but in the presence of their aunt, nieces could not. These combined results point to a relatedness threshold for effective nepotistic aiding above the aunt–niece level of relatedness. Analysis of 1002 interventions received by juvenile females from various categories of adult female kin in the unmanipulated, complete group confirmed this hypothesis. Finally, 11 years of data on the distribution of female homosexual activity according to relatedness provided complementary evidence for the threshold hypothesis. Non-kin females commonly engaged in homosexual interactions, as did aunts and nieces, but closer kin never did, suggesting that aunts and nieces do not recognize each other as kin for the purpose of sexual interactions. Together, these results point to a relatedness threshold for nepotistic aiding at r=0.25 and suggest that this threshold is not behaviour-specific but generalized.
A detailed comparison of Macaca fuscata and Papio anubis reveals that female aggression to males has an effect on male association with females in both species, but only in M. fuscata do females appear to be able to limit the number of males in their troop. It is suggested that this is the reasons why 'solitary' males are commonly reported in M. fuscata, but rare in P. anubis, and may be related ultimately to the different degrees of sexual dimorphism in the two species.
The evidence reviewed suggests that in all mammalian species the adult male's ability to display masculine coital behavior depends in part on exposure of the developing brain to testicular testosterone or its metabolites. In many mammals, particularly rodents, ruminants, and some carnivores, perinatal exposure to androgen also causes behavioral defeminization, i.e., reduced capacity to display typically feminine coital behavior in response to gonadal hormones in adulthood. The data reviewed suggest that no such process occurs in certain other mammalian species, including ferret, rhesus monkey, marmoset, and man. Testicular androgen may cause behavioral defeminization only in those species in which expression of feminine sexual behavior normally depends on the neural action of progesterone, acting synergistically with estradiol; new data support this claim in the ferret. The possible contribution of estrogenic and 5 alpha-reduced androgenic metabolites of testosterone to the occurrence of behavioral masculinization and defeminization is considered in those mammalian species for which data are available.
Thesis (Ph. D.)--Harvard University, 1976. Bibliography: leaves 270-287.
Theorists argue that mortality in male mammals should be higher than that of females, and many studies of primates followed across the life course have found this to be the case. This study examines mortality patterns in the rapidly expanding Arashiyama West (Texas) population of Japanese macaques (Macaca fuscata) and finds that males have a significantly lower median survival age (12.2 years) in comparison to females (20.5 years). Males and females are born in equal proportions, but by adulthood there are 2-5 females to every male. Males are at higher risk of falling victim to infectious diseases and human-related causes of death, and they are more likely to "disappear" from the population, which is inferred to result largely from emigration. There are no significant sex differences in the risks of dying from predation, non-infectious illnesses, neonatal defect, or social stress. Males become more susceptible to mortality than females once they reach sexual maturity, and they remain at greater risk than females until their old age. There is no evidence that one sex or the other is at greater risk of dying as infants, or as juveniles. Comparing males of different age classes, adolescent and adult males are more likely to die and to disappear than are juvenile males. These findings support the "high-risk, high-gain" hypothesis that males are mainly lost to the population because of their risk-taking behaviors after sexual maturity, rather than the "fragile male" hypothesis that males are more vulnerable to mortality during the period of growth and development.
Proximate and ultimate biological theories for understanding sexual behavior predict that sexual dimorphism in sexual partner preference should be ubiquitous in the animal kingdom. A review of the literature found evidence for same-sex sexual partner preference in a small number of species (female pukekos, cows, domestic rams, female Uganda kobs, female Japanese macaques). Thus, theoretical predictions concerning the development and evolution of sexual partner preference appear to hold true except for a handful of exceptional species. Why individuals in some animal species exhibit same-sex sexual partner preference remains the object of debate. At a proximate level, domestic rams that exhibit same-sex sexual partner preference have been shown to differ in certain aspects of their neurobiology and physiology from rams that do not exhibit such a preference. It remains unclear, however, as to whether these differences are produced by sex-atypical perinatal exposure to androgens and their estrogenic metabolites. At an ultimate level, numerous functional hypotheses for same-sex sexual partner preference have been tested in female Japanese macaques but have failed to receive support. Understanding why same-sex sexual partner preference evolves in some species may involve abandoning a strictly functional perspective and, instead, approaching the issue from the perspective of each species' unique evolutionary history.
The relationship of the ovarian cycle phase to same-sex mounting activity in adult female Japanese macaques (Macaca fuscata) was studied during the 1997/1998 mating season. Fecal samples were collected from eight female subjects two to three times per week and analyzed by enzyme immunoassay for fecal hormone levels. Hormone profiles of estrone (E1) and pregnanediol (PdG) were used to separate ovarian cycles into three phases: follicular, periovulatory, and luteal. Patterns of same-sex and heterosexual mounting behavior in the females were analyzed for phase variation during conceptive cycles. Same-sex mounting among female Japanese macaques occurred most frequently during the follicular and periovulatory phases of the cycle, and not at all during the luteal phase, paralleling the pattern found in heterosexual mounting behavior. These findings suggest a link between hormonal fluctuations and patterns of sexual mounting, regardless of whether the partner is of the same or opposite sex.
Female Japanese macaques (Macaca fuscata) in certain populations are unusual in that they exhibit male-typical patterns of mounting behavior and sexual-partner preference. The goal of this study was to determine whether female Japanese macaques, from one such population, employ male-typical behavioral tactics to disrupt existing homosexual consortships, as well as to acquire and retain same-sex sexual partners. "Harassment" of homosexual consortships occurred when a sexually motivated, third-party male or female interrupted a consorting female couple by displacing or aggressing them. Sexual harassment was a male-typical strategy for disrupting existing homosexual consortships, but was rarely performed by females. "Intrusions" occurred when a male or female competitor attempted to acquire exclusive access to a female engaged in a homosexual consortship by targeting that female as the focus of competition and her partner as his/her competitor. "Sexual coercion" occurred when one individual alternately sexually solicited and aggressed another individual as part of the same behavioral sequence during an intrusion. Males employed consortship intrusions and sexual coercion when they attempted to acquire female sexual partners that were already engaged in homosexual consortships, but females rarely did so. However, females did employ male-typical patterns of aggressive competition and sexual coercion to retain same-sex sexual partners when confronted with male competitors' attempts to usurp those partners. These results indicate that female sexual activity during homosexual consortships is not uniformly "masculine" in expression, but rather is a mixture of male- and female-typical behaviors.
Mounting is generally considered to be a male-typical behavior. Female Japanese macaques, in certain populations, are unusual, in that they routinely mount other females. In this study, we examined to what extent female Japanese macaques mount same-sex partners in a male-typical manner. We compared the mount postures males and females adopt and their rate of pelvic thrusting. In addition, we employed a modified form of Laban Movement Analysis (LMA) to compare patterns of pelvic movement during mounts. LMA is a universal language for movement that describes quantitative features of movement, such as changes in the relation of the body segments, as well as qualitative features, such as the style of movements. Our results indicate that female Japanese macaques do not mount in a male-typical manner. Females exhibited a much greater variety of mount postures than did males. Some of the most common types of mount postures employed by females were never exhibited by males. Females performed fewer pelvic thrusts per mount than males, but they executed more pelvic movements per mount, as well as, greater variety and complexity of movement. In addition, the qualitative style of pelvic mounting that females employed differed, in general, from that of males. We argue that these sex differences in mounting can be explained by the fact that both sexes sought sexual reward via genital stimulation during mounting, but they did so in different ways owing to the constraints imposed by their genital architecture. This study raises the larger question as to what constitutes a male-typical or female-typical behavior.
Female Japanese macaques (Macaca fuscata), in certain captive and free-ranging populations, frequently engage in same-sex mounting. Traditionally, same-sex mounting interactions in animals have been characterized as "sociosexual," that is, sexual in terms of their superficial form, but enacted to facilitate adaptive social goals. Sexual motivation is rarely ascribed to sociosexual interactions because their adaptive functions are often seen as their primary purpose, thus diminishing, or even negating, any sexual component that such activity might have. A substantial number of studies indicate that female-female mounting in Japanese macaques is not a sociosexual behavior. In contrast, several lines of circumstantial evidence suggest that these interactions are, indeed, sexual. In this study, we documented patterns of vulvar, perineal, and anal (VPA) stimulation during same-sex mounting in female Japanese macaques. During the majority of female-female mounts analyzed, female mounters engaged in repetitive VPA stimulation. Two forms of VPA manipulation by female mounters were observed. First, while sitting in a jockey-style position on the mountee, a female mounter would rub her VPA region against the mountee's back. Males never executed this type of mount posture or pelvic movement. Second, female mounters rubbed their VPA regions with their tails during same-sex mounts. Females mounters moved their tails in a voluntary, sex-specific manner and were never observed to do so in non-sexual contexts. Given the primary role of the VPA regions in mediating sexual response in primates, the results of this research provide direct evidence bearing on the sexual nature of female-female mounting in Japanese macaques and give further support for the conclusion that the term "homosexual behavior" is an appropriate label for these interactions.
Comparing the behavior of heterosexual and homosexual persons can provide insight into the origins of heterosexual sex differences in psychology. Evidence indicates that, aside from sexual partner preference, the mating psychology of homosexual men is sex-typical whereas that of homosexual women tends to be more sex-atypical. The current study examined one aspect of mating psychology, mate retention behavior, and tested whether homosexual men and women were sex-typical or sex-atypical for those mate retention tactics where heterosexual men and women differed. Men and women in heterosexual and homosexual relationships were asked to provide information regarding their partners' mate retention behavior by using the Mate Retention Inventory Questionnaire. Heterosexual men and women differed significantly for six of the 19 mate retention tactics considered. With respect to the six mate retention tactics where heterosexual sex differences existed, homosexual men behaved in a sex-typical manner for five of the tactics, whereas homosexual women behaved in a sex-atypical manner for all six tactics. We discuss the significance of these findings for explaining the origins of the mate retention behavior of heterosexual men and women. In addition, we consider what the pattern of sex-typical and sex-atypical mating psychology among homosexual men and women, respectively, suggests in regard to sex differences in the development of mating psychology and the development of homosexual persons.
Female Japanese macaques (Macaca fuscata), in certain populations, routinely engage in female-male mounting. In this study, we documented patterns of vulvar, perineal and anal (VPA) stimulation during female-male mounting in Japanese macaques. During approximately 45% of the female-male mounts analyzed, two thirds of female mounters engaged in VPA stimulation. Given the VPA region's primary role in mediating sexual response, the results of this research provide direct evidence bearing on the sexual nature of a substantial proportion of female-male mounts in Japanese macaques.
Dispersal and philopatry
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Socio-sexual signals and their intra-specific imitation among primates
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The consort relationship in a troop of Japanese monkeys
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Sex differences in the speci-ficity of sexual behavior, fantasy, and romantic attraction. In: Poster session at the Meeting of the International Academy of Sex Research, Amsterdam, The Netherlands Multiple comparison procedures: the practical solution
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Japanese macaque female sexual behavior: a comparison of Arashiyama East and West
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