Joseph Soltis

• Project Manager at Disney Research

Common hippos (Hippopotamus amphibius) live in murky waters and produce a variety of acoustic signals including underwater click trains considered to be social in function. We tested the hypothesis that click trains may function for underwater detection. We used observational and experimental methods involving 16 captive hippos to document the occu...

Asian elephants (Elephas maximus) are threatened primarily by habitat loss and human-elephant conflict. In addition to establishing protected areas and corridors for wildlife, empowering farmers to protect their crops is crucial for Asian elephant conservation [1,2]. Elephants can habituate to artificial deterrents, hence natural biological alterna...

A clear need for evidence-based animal management in zoos and aquariums has been expressed by industry leaders. Here, we show how individual animal welfare monitoring can be combined with measurement of environmental conditions to inform science-based animal management decisions. Over the last several years, Disney's Animal Kingdom® has been underg...

Accelerometers can be used to monitor animal behavior remotely, but validation is required for each species. Previously, we showed that accelerometer data in collars could be used to identify specific behaviors in African elephants Loxodonta africana, using complex analytical methods. Here, we show that simple methods can also be used to identify e...

Resting behaviors are an essential component of animal welfare but have received little attention in zoological research. African savanna elephant (Loxodonta africana) and Asian elephant (Elephas maximus) rest includes recumbent postures, but no large-scale investigation of African and Asian zoo elephant recumbence has been previously conducted. We...

Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestio...

Resting behaviors are an essential component of animal welfare but have received little attention in zoological research. African savanna elephant (Loxodonta africana) and Asian elephant (Elephas maximus) rest includes recumbent postures, but no large-scale investigation of African and Asian zoo elephant recumbence has been previously conducted. We...

Validation test of accelerometer using video analysis. Two Asian zoo elephants wore accelerometers in anklets for two consecutive nights and accelerometer data were compared with video recordings of recumbence activity. Additionally, Subject #2 wore a second accelerometer in the same anklet to test inter-accelerometer reliability. The most notable...

Mean recumbence and standard error for all subjects (n = 72). (DOCX)

This study describes the acoustic and behavioral repertoires of the common hippopotamus (Hippopotamus amphibius). Simultaneous audio and video recordings were collected of male and female hippos at Disney's Animal Kingdom(®). Visual inspection of spectrograms resulted in classifying signals into three main categories (burst of air, tonal, and pulse...

Animal welfare in zoos is most often described as a combination of physical and psychological well-being. Welfare is defined as good if an animal is healthy, comfortable, well-nourished, safe and able to express species-typical behaviours. An animal’s welfare is considered poor if it is suffering from unpleasant states such as pain, fear or distres...

Assessment of animal internal “state” – which includes hormonal, disease, nutritional, and emotional states – is normally considered the province of laboratory work, since its determination in animals in the wild is considered more difficult. However, we show that accelerometers attached externally to animals as diverse as elephants, cockroaches, a...

The Samburu pastoralists of Northern Kenya co-exist with African elephants, Loxodonta africana, and compete over resources such as watering holes. Audio playback experiments demonstrate that African elephants produce alarm calls in response to the voices of Samburu tribesmen. When exposed to adult male Samburu voices, listening elephants exhibited...

The Key Largo woodrat (Neotoma floridana smalli) is an endangered rodent endemic to the island of Key Largo, FL. There is little information on vocal communication in this species and descriptions of the acoustic structure of calls are lacking. A captive breeding program was established as part of the recovery plan for the species, providing the op...

ABSTRACT: Accelerometers are motion-detection devices that, when attached to animals, are capable of detecting body orientation, overall activity levels, and specific behavior patterns. We deployed accelerometers in order to study the hypothesis that accelerometer output would allow us to distinguish between 4 behavior patterns in 3 adult female Af...

Troop takeover is common in one-male primate groups, but there are few reports in multimale groups. Japanese macaques (Macaca fuscata) form multimale groups and males commonly join troops at the bottom rank. On Yakushima island, however, where group size is relatively small, entrance into groups at the alpha position is also observed. This paper re...

As in other mammals, there is evidence that the African elephant voice reflects affect intensity, but it is less clear if positive and negative affective states are differentially reflected in the voice. An acoustic comparison was made between African elephant "rumble" vocalizations produced in negative social contexts (dominance interactions), neu...

Butterfly Family Response to Bee Rumble Playback. This video shows a typical response by elephants to the bee rumble playback. Here the Butterfly Family are resting under a tree when the rumble is heard to the right of the picture coming from the hidden wireless speaker. The response to move away is quick and the matriarch is seen headshaking as sh...

Recording of Bee Rumble. These three “bee rumbles” were recorded from an elephant family responding to bee stimuli and were used in the rumble playback experiments. (0.40 MB WAV)

White Noise Rumble. These three “white noise rumbles” were recorded from an elephant family responding to bee stimuli where the second formants were experimentally lowered in frequency location to resemble rumbles produced in response to white noise playbacks. (0.36 MB WAV)

Control Rumbles. These three “control rumbles” were recorded pre-stimulus from the same elephant family and were matched for duration and amplitude to the other rumble playbacks. (0.57 MB WAV)

Unlike the smaller and more vulnerable mammals, African elephants have relatively few predators that threaten their survival. The sound of disturbed African honeybees Apis meliffera scutellata causes African elephants Loxodonta africana to retreat and produce warning vocalizations that lead other elephants to join the flight. In our first experimen...

Research on vocal communication in African elephants has increased in recent years, both in the wild and in captivity, providing an opportunity to present a comprehensive review of research related to their vocal behavior. Current data indicate that the vocal repertoire consists of perhaps nine acoustically distinct call types, "rumbles" being the...

African elephant rumbles are harmonically rich vocalizations with clear formant structure. The low‐frequency, high amplitude nature of rumbles is consistent with the observed large vocal production anatomy. Examination of formant locations and inter‐formant dispersion implicates the trunk in addition to the oral cavity in rumble production. Adult f...

Cotton-top tamains (Saguinus oedipus) are a critically endangered primate found only in Colombia. Efforts to conserve this species are centered on developing effective management plans that integrate biological information regarding population dynamics and factors that influence their survival. This study documented infants born to wild cotton-top...

Affective states are thought to be expressed in the mammalian voice, but such investigations are most common in primates. Source and filter features of rumbles were analyzed from 6 adult female African elephants (Loxodonta africana) at Disney's Animal Kingdom. Rumbles produced during periods of minimal social interaction ("low affect") were compare...

Research on African elephant (Loxodonta africana) vocal communication has increased in recent years, yet there has been very little data collected on the vocal production of infant African elephants. Vocalizations were recorded from a group of five adult female African elephants and 3 dependent offspring (1 male and 2 female) at Disney's Animal Kin...

The movements of elephants in captivity have been an issue of concern for animal welfare activists and zoological professionals alike in recent years. In order to fully understand how movement rates reflect animal welfare, we must first determine the exact distances these animals move in the captive environment. We outfitted seven adult female Afri...

In public discussions of animal rights and welfare, we as members and proponents of zoological institutions often face significant challenges addressing the concerns of our detractors due to an unfortunate deficiency in systematically collected and published data on the animals in our collections. In the case of elephants, there has been a paucity...

No Abstracts.

The ability to utilize contact calls to facilitate reunions with social partners has been documented in a number of species showing a fission/fusion social organization. Field observations and playback experiments suggest that African elephants use low-frequency rumble vocalizations to reunite with their herd members following periods of fission. U...

Female African elephants are thought to exchange 'rumble' vocalizations, but such temporally associated calls may not constitute communicative events. Affiliated females are more likely to engage in antiphonal calling, but affiliation is defined according to time spent in proximity. Affiliated partners may vocalize in sequence simply because their...

In this paper, we evaluate the use of appended jitter and shimmer speech features for the classification of human speaking styles and of animal vocalization arousal levels. Jitter and shimmer features are extracted from the fundamental frequency contour and added to baseline spectral features, specifically Mel-frequency cepstral coefficients (MFCCs...

Female African elephants (Loxodonta africana) engage in antiphonal exchanges of rumble vocalizations. In this study, female African elephants (N=7) housed at Disney’s Animal Kingdom were outfitted with audio‐recording collars and videotaped during 50 1‐hour observation sessions (conducted in 2002). We found that production of the antiphonal respons...

Emotional arousal is expressed in the voiced sounds of primates and other mammals, but there are no consistent acoustic measures used and few comparative analyses. We apply a representative suite of source and filter measurements to rhesus macaque (Macaca mulatta) coo calls on Cayo Santiago, Puerto Rico, and African elephant (Loxodonta africana) ru...

Much sexual selection theory is based on the idea that ejaculate is cheap. Since further details are unknown our aim was to determine the energy that primate males require for ejaculate production. We addressed this problem by measuring the energy content (in kJ) of ejaculates from Japanese macaques (Macaca fuscata) using standard bomb calorimetry....

African elephants, Loxodonta africana, are well known for their use of a low-frequency ‘rumble’ vocalization, which is thought to function in long-distance communication. Less work, however, has been conducted on short-distance communication within groups, and on spontaneously occurring vocal exchanges among identified individuals in particular. Th...

The most common vocalization of the African elephant, Loxodonta africana, is the rumble, but there is no consensus as to how many rumble subtypes exist. From the standpoint of social function, many types of rumble have been proposed. From a structural standpoint, however, few studies have examined detailed acoustic measurements of a large number of...

The hormone prolactin is implicated in infant care-giving by parents and allo-parents in a variety of species. Adult female squirrel monkeys (Saimiri spp.) engage in allo-mothering behavior, which includes carrying and nursing infants, but communal care of offspring has not been investigated from an endocrine standpoint in this taxon. We attempted...

We studied masturbatory behavior of males over a 14-mo period in free-ranging Japanese macaques (Macaca fuscata yakui) on Yakushima island, Japan. We distinguished 2 types: (1) masturbation only and (2) masturbation with final ejaculation. Both types occurred in all 15 adult troop males. We calculated masturbation only as an index (M/h). It occurre...

In this article I evaluate recent attempts to illuminate the human infant cry from an evolutionary perspective. Infants are born into an uncertain parenting environment, which can range from indulgent care of offspring to infanticide. Infant cries are in large part adaptations that maintain proximity to and elicit care from caregivers. Although the...

The majority of the commentaries focused on excessive crying and colic and included two major themes: the consideration of proximate physiological mechanisms, and challenges to my interpretation of the signal functions of early infant crying amount. I initially concluded that none of the competing signaling hypotheses enjoyed strong support, but I...

The mass mortality of wild Japanese macaques (Macaca fuscata Blyth) was observed in a warm temperate forest of Yakushima, southern Japan. Demographic changes of eight troops between August 1998 and August 1999 were studied and 56% of macaques disappeared from the five intensively studied troops. Mortality varied among troops: two troops became exti...

Variable environmental and social conditions influence hypothalamic-pituitary-adrenal activity in captive animals. Socially separated and individually housed animals generally experience increased cortisol secretion compared to animals housed with conspecifics, and social companionship can buffer the stress response when exposed to challenges such...

In Batsman's 1 landmark experiments, he placed male and female fruit flies in bottles with varying numbers of opposite-sex mates. Male production of offspring increased with increasing numbers of female mates, but female production of offspring did not increase with increasing numbers of male mates. This phenomenon was caused by a fundamental repro...

Adult female squirrel monkeys (genus Saimiri) that are socially familiar often exchange the chuck vocalization, which differs acoustically across individuals. We used behavioral observations, vocalization playback experiments, and analysis of the acoustic properties of vocalizations to investigate the effect of caller identity and acoustic structur...

Although females may require only one mating to become inseminated, many female animals engage in costly mating with multiple males. One potential benefit of polyandrous mating is gaining parental investment from multiple males. We developed two game theoretic models to explore this possibility. Our first model showed that male care of multiple fem...

Japanese macaques reside in large, mixed-sex social groups in which various reproductive strategies of both sexes operate simultaneously. This report represents the first study combining behavioural and genetic data to examine the interaction of male and female reproductive strategies in primates (N=15 adult males, N=15 adult females, Yakushima Isl...

The most commonly occurring elephant vocalization is the rumble, a frequency‐modulated call with infrasonic components. Upwards of ten distinct rumble subtypes have been proposed, but little quantitative work on the acoustic properties of rumbles has been conducted. Rumble vocalizations (N=269) from six females housed at Disney’s Animal Kingdom wer...

Infanticide was observed for the first time in a wild, non-provisioned troop of Japanese macaques on Yakushima Island, Japan. Eight adult resident males attacked unweaned infants in the pre- and early mating season, and one infanticide was observed directly. These attacks were not consistent with the social pathology, side effect of male aggression...

Female primates may adopt special feeding, foraging, and social strategies around the time of giving birth. We observed 8 females during the prepartum period, the day of birth, and the postpartum period in a wild troop of Japanese macaques (Macaca fuscata yakui) on Yakushima Island, Japan. We collected data on their activity budgets, quantitative f...

Heterosexual relationships during one mating season were examined in a wild troop of Japanese macaques (Macaca fuscata yakui) on Yakushima Island, Japan. Validation tests of putative mate choice behaviors demonstrated that female initiation and maintenance of proximity, female lookback at the male, and sexual presents to the male, were associated w...

Female Japanese macaques (Macaca fuscata) are noted for mating with multiple males and for their ability to exert mate choice. In a captive group of Japanese macaques housed at the Primate Research Institute of Kyoto University, Japan, behavioral and endocrine data were combined to examine female mating strategies. During one breeding season, daily...

Mate choice is defined as a behavioural pattern in one sex which increases the probability of fertile matings with certain members of the opposite sex. The chosen sex may use force, however, to coerce matings from reluctant members of the choosing sex. In a confined group of Japanese macaques, Macaca fuscata fuscatahoused at the Primate Research In...

Mating and reproductive outcomes are the product of the potentially conficting strategies of breeding males and females. In a captive group of Japanese macaques, Macaca fuscata fuscatabehavioural, endocrine and genetic data were combined to assess the independent effects of male-male competition and female mate choice on mating and reproductive suc...

Functionalists believe that social and cultural variation results from adaptation at the group level. Such explanations are controversial for two reasons: (1) Extensive analysis of mathematical models of group selection by evolutionary biologists suggests that group selection is unlikely to be important. (2) Group extinctions are too rare to genera...

Inthis paper, weevaluate theuseofappended jitter and shimmerspeech features fortheclassification ofhuman speaking styles andofanimal vocalization arousal levels. Jitter and shimmerfeatures areextracted fromthe fundamental frequency contourandaddedtobaseline spectral features, specifically Mel-frequency Cepstral Coefficients (MFCCs)forhumanspeech an...