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Vervet Monkey Alarm Calls: Semantic Communication In A Free-Ranging Primate

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Abstract

Vervet monkeys (Cercopithecus aethiops) at Amboseli, Kenya, give acoustically different alarm calls to different predators. Each alarm evokes contrasting, seemingly adaptive, responses. Animals on the ground respond to leopard alarms by running into trees, to eagle alarms by looking up, and to snake alarms by looking down. In a 14-month field study examining the semantic properties of alarm calls, we played tape-recorded alarms to vervets in the absence of actual predators and filmed the monkeys' responses. Playbacks confirmed observations and showed that (1) alarm length, amplitude and alarmist's age/sex class had little effect on response quality, and (2) context was not a systematic determinant of response. We conclude that vervet alarm calls function to designate different classes of external danger.

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... The emergence of language is considered a crucial occurrence in the evolution of human history, an innovation that radically changed the character of human interactions [11]. Attempts to shed light on the evolution of human language have been undertaken by investigators working in a host of research domains investigating: the social behavioral characteristics of primates [12,13], the unity and diversity of human language [14,15], the development of language in children [16], and the genetic and anatomical correlates of language expertise [17,18]. It would seem, in any case, that at some point millions of years ago language began evolving when hominids started using sounds to share meanings and thoughts with one another [11] and establish social interactions. ...
... Communicating danger, the presence of a predator, or the amount of resources that are available are examples of meaning-making activities that can be expressed in widely different ways. For instance, monkeys use different alarm calls to warn one another depending on the classification of the predator [13,30]. But it is the waggle dance of honeybees that represents the most striking type of creative, non-stereotyped language within the animal kingdom. ...
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The linguistic behavior of humans is usually considered the point of reference for studying the origin and evolution of language. As commonly defined, language is a form of communication between human beings; many have argued that it is unique to humans as there is no apparent equivalent for it in non-human organisms. How language is used as a means of communication is examined in this essay from a biological perspective positing that it is effectively and meaningfully used by non-human organisms and, more specifically, by plants. We set out to draw parallels between some aspects characterizing human language and the chemical communication that occurs between plants. The essay examines the similarities in ways of communicating linked to three properties of language: its combinatorial structure, meaning-making activities and the existence of dialects. In accordance with the findings of researchers who have demonstrated that plants do indeed communicate with one another and with organisms in their environment, the essay concludes with the appeal for an interdisciplinary approach conceptualizing a broader ecological definition of language and a constructive dialogue between the biological sciences and the humanities.
... A problem arises when there is a need to communicate the qualities of others. For example, Vervet monkeys have different calls that identify different types of predators [32]. This requires a capacity for cataloguing the predators in categories and communicating them to receivers that understand the codes that identify such categories. ...
... Reputation consists of a belief about a third individual based on information provided by another. Reputation building is important especially in the establishment of direct and indirect cooperation between individuals that are not directly on the receiving end of the altruistic act [32]. ...
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The word “belief” evokes concepts such as religious or political beliefs, however there is more to belief than cultural aspects. The formation of beliefs depends on information acquired through subjective sampling and informants. Recent developments in the study of animal cognition suggest that animals also hold beliefs and there are some aspects that underly the formation of beliefs which are shared with other animal species, namely the relationship between causality, predictability and utility of beliefs. This review explores the biological roots of belief formation and suggests explanations for how evolution shaped the mind to harbour complex concepts based on linguistic structures held by humans. Furthermore, it suggests that beliefs are shaped by the type and process of information acquisition which progresses through three levels of complexity.
... Acoustic signals produced only in specific contexts become linked to a specific signal function and thus can provide information about their general environment. For example, the presence of predators can be advertised through alarm calls (Seyfarth et al. 1980;Blumstein and Armitage 1997a;Macedonia and Evans 2010;Moran 2010), detection of food through species-specific foraging calls (Chapman and Lefebvre 1990;Brown et al. 1991;Hauser et al. 1993;Mahurin and Freeberg 2009), and the emitter's social intentions through aggression or courtship calls (Owen et al. 2006;Charlton et al. 2007;Ballentine et al. 2008;Faragó et al. 2010). On a secondary level, vocalizations from the species vocal repertoire convey both static and dynamic information on the emitter . ...
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The cape fur seal is one of the most colonial mammal species in the world. Breeding colonies are composed of harems held by mature males (older than 10 years) with up to 30 females and their pups, while roaming subadult males (younger and socially immature) are kept away from bulls’ territories. As in other pinnipeds, cape fur seals are highly vocal and use acoustic signals in all their social interactions. Males produce barks—short vocalizations always produced in sequences—for territorial defense, mating behaviors, and agonistic interactions. These calls convey information about the sex, age class, and individual identity. This study investigated whether motivational cues such as the arousal state can be encoded in territorial males’ barks and whether these cues are decoded by listening sub-adult males. The rate (number of calls per unit of time) and fundamental frequency of barks were found to significantly increase during high arousal state interactions (i.e., male-male confrontation) compared to spontaneous barks. Playback experiments revealed that subadult males responded with a higher level of vigilance when territorial males’ barks had a faster bark rate. This mechanism of decoding the bulls’ arousal state from barks will likely constitute an advantage for both bulls and the subadult males, by avoiding or reducing physical conflicts, and thereby reducing energy expenditure and the risk of injury. This study is the first experimental evidence of cape fur seals’ using vocal rhythmic patterns to modulate their social interactions.
... Revealingly, these conclusions have done little to slow the pace of research in this area. To wit, at the close of 2020 (and according to Google Scholar), the original 1980 Science paper on vervet alarm calls had been cited almost 1,500 times, and a companion paper published the same year in the journal Animal Behavior, also under the banner of semantic communication (Seyfarth et al., 1980b), had been cited just over 1,000 times -with no sign that the rate of citation of either paper has slowed since most of the above-noted conclusions were reached. On the contrary, the rate of citation for both papers is actually higher post-2000 compared to before. ...
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In 1980, Robert Seyfarth, Dorothy Cheney and Peter Marler published a landmark paper in Science claiming language-like semantic communication in the alarm calls of vervet monkeys. This article and the career research program it spawned for its authors catalyzed countless other studies searching for semantics, and then also syntax and other rarefied properties of language, in the communication systems of non-human primates and other animals. It also helped bolster a parallel tradition of teaching symbolism and syntax in artificial language systems to great apes. Although the search for language rudiments in the communications of primates long predates the vervet alarm call story, it is difficult to overstate the impact of the vervet research, for it fueled field and laboratory research programs for several generations of primatologists and kept busy an equal number of philosophers, linguists, and cognitive scientists debating possible implications for the origins and evolution of language and other vaunted elements of the human condition. Now 40-years on, the original vervet alarm call findings have been revised and claims of semanticity recanted; while other evidence for semantics and syntax in the natural communications of non-humans is sparse and weak. Ultimately, we are forced to conclude that there are simply few substantive precedents in the natural communications of animals for the high-level informational and representational properties of language, nor its complex syntax. This conclusion does not mean primates cannot be taught some version of these elements of language in artificial language systems – in fact, they can. Nor does it mean there is no continuity between the natural communications of animals and humans that could inform the evolution of language – in fact, there is such continuity. It just does not lie in the specialized semantic and syntactic properties of language. In reviewing these matters, I consider why it is that primates do not evince high-level properties of language in their natural communications but why we so readily accepted that they did or should; and what lessons we might draw from that experience. In the process, I also consider why accounts of human-like characteristics in animals can be so irresistibly appealing.
... A robust finding in animal behaviour research is that many social species produce acoustically distinct alarm calls to different predators. In primates, the phenomenon has first been studied systematically in East African vervet monkeys (Cercopithecus aethiops) with evidence for acoustically distinct alarm calls to martial eagles, leopards and pythons (Struhsaker 1967) and corresponding, adaptive anti-predator responses in listeners (Seyfarth et al. 1980). Similar findings have been reported in a range of other species, such as Diana Communicated by D P. Watts monkeys (Cercopithecus diana, Zuberbühler et al. 1997), Campbell's monkeys (Cercopithecus campbelli, Zuberbühler 2001), putty-nosed monkeys (Cercopithecus nictitans, Arnold and Zuberbühler 2006), sooty mangabeys (Cercocebus atys, Range and Fischer 2004), lemurs (Eulemur fulvus rufus and Propithecus verreauxi, Fichtel and Kappeler 2002), meerkats (Suricata suricatta, Manser 2001) and many bird species (Suzuki 2012;Grieves et al. 2014;Cunningham and Magrath 2017). ...
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Forest monkeys often form semi-permanent mixed-species associations to increase group-size related anti-predator benefits without corresponding increases in resource competition. In this study, we analysed the alarm call system of lesser spot-nosed monkeys, a primate that spends most of its time in mixed-species groups while occupying the lowest and presumably most dangerous part of the forest canopy. In contrast to other primate species, we found no evidence for predator-specific alarm calls. Instead, males gave one general alarm call type (‘kroo’) to three main dangers (i.e., crowned eagles, leopards and falling trees) and a second call type (‘tcha-kow’) as a coordinated response to calls produced in non-predatory contexts (‘boom’) by associated male Campbell’s monkeys. Production of ‘kroo’ calls was also strongly affected by the alarm calling behaviour of male Campbell’s monkeys, suggesting that male lesser spot-nosed monkeys adjust their alarm call production to another species’ vocal behaviour. We discuss different hypotheses for this unusual phenomenon and propose that high predation pressure can lead to reliance on other species vocal behaviour to minimise predation. Significance statement Predation can lead to the evolution of acoustically distinct, predator-specific alarm calls. However, there are occasional reports of species lacking such abilities, despite diverse predation pressure, suggesting that evolutionary mechanisms are more complex. We conducted field experiments to systematically describe the alarm calling behaviour of lesser spot-nosed monkeys, an arboreal primate living in the lower forest strata where pressure from different predators is high. We found evidence for two acoustically distinct calls but, contrary to other primates in the same habitat, no evidence for predator-specific alarms. Instead, callers produced one alarm call type (‘kroo’) to all predator classes and another call type (‘tcha-kow’) to non-predatory dangers, but only as a response to a specific vocalisation of Campbell’s monkeys (‘boom’). The production of both calls was affected by the calling behaviour of Campbell’s monkeys, suggesting that lesser spot-nosed monkey vocal behaviour is dependent on the antipredator behaviour of other species. Our study advances the theory of interspecies interactions and evolution of alarm calls.
... They are certainly difference-makers; assuming certain background conditions, if an intervention is made on the signal, a change in behaviour ensues. For example, whether a vervet monkey produces an alarm call or not makes a difference with respect to the behaviour of other members of group (Seyfarth et al. 1980). Likewise, altering the number of waggles performed by a bee dancing at the nest makes a difference concerning the distance at which other bees will search for nectar (von Frisch, 1967). ...
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Recent research on bacteria and other microorganisms has provided interesting insights into the nature of life, cooperation, evolution, individuality or species. In this paper, I focus on the capacity of bacteria to produce molecules that are usually classified as 'signals' and I defend two claims. First, I argue that certain interactions between bacteria should actually qualify as genuine forms of communication. Second, I use this case study to revise our general theories of signaling. Among other things, I argue that a plausible requirement for a state to qualify as a signal is that it is a minimal cause.
... Anim Biotelemetry (2021) 9:28 environment, such as variations in temperature [3,4], habitat [5,6], social systems [7] or prey availability [8,9]. Traditionally, the assessment of activity budgets has required long hours of observations in the field [10], and have been applied to various species (e.g., in primates [11][12][13], birds [14,15], deer [16], rodents [17], fish [18], bats [19], insects [20], seals [21], cetaceans [22]). However, this is not always practical. ...
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Background Studies on animal behaviour often involve the quantification of the occurrence and duration of various activities. When direct observations are challenging (e.g., at night, in a burrow, at sea), animal-borne devices can be used to remotely record the movement and behaviour of an animal (e.g., changing body posture and movement, geographical position) and/or its immediate surrounding environment (e.g., wet or dry, pressure, temperature, light). Changes in these recorded variables are related to different activities undertaken by the animal. Here we explored the use of animal-borne acoustic recorders to automatically infer activities in seabirds. Results We deployed acoustic recorders on Cape gannets and analysed sound data from 10 foraging trips. The different activities (flying, floating on water and diving) were associated with clearly distinguishable acoustic features. We developed a method to automatically identify the activities of equipped individuals, exclusively from animal-borne acoustic data. A random subset of four foraging trips was manually labelled and used to train a classification algorithm (k-nearest neighbour model). The algorithm correctly classified activities with a global accuracy of 98.46%. The model was then used to automatically assess the activity budgets on the remaining non-labelled data, as an illustrative example. In addition, we conducted a systematic review of studies that have previously used data from animal-borne devices to automatically classify animal behaviour ( n = 61 classifications from 54 articles). The majority of studies (82%) used accelerometers (alone or in combination with other sensors, such as gyroscopes or magnetometers) for classifying activities, and to a lesser extent GPS, acoustic recorders or pressure sensors, all potentially providing a good accuracy of classification (> 90%). Conclusion This article demonstrates that acoustic data alone can be used to reconstruct activity budgets with very good accuracy. In addition to the animal’s activity, acoustic devices record the environment of equipped animals (biophony, geophony, anthropophony) that can be essential to contextualise the behaviour of animals. They hence provide a valuable alternative to the set of tools available to assess animals’ behaviours and activities in the wild.
... The term "alarm calls" is widely used in studies on birds and mammals to indicate that callers potentially inform or warn conspecifics about predators nearby. Vervet monkeys (Chercopithecus aethiops, Cercopithecidae) emit different alarm calls depending on the type of predator (python, eagle, leopard), and conspecifics respond accordingly by searching the bottom or fleeing into bushes or trees (Seyfarth et al., 1980). In fishes, the terms "startle" and "warning calls" have been used when fish were confronted by a known predator (Myrberg, 1981). ...
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Predation is a major ecological constraint shaping behaviour and communication in animals. Several fish species are known to modify their foraging, agonistic and reproductive behaviour in the presence of predators. However, close to nothing is known about how predators affect sound production in fishes. This paper reviews how vocal fish increase their chance of survival by modifying intraspecific acoustic communication and by producing sounds directed towards predators. Field studies showed that toadfish, drums and squirrelfish reduced the number and loudness of calls when dolphin sounds were played back. These studies lack behavioural observations, leaving the question open how individual fish respond to predation threat. Croaking gouramis (Trichopsis vittata, Osphronemidae) reduced acoustic and visual signalling during dyadic contests and refrained from escalated behaviour when detecting a predator in an adjacent tank. This indicates that gouramis increase their vigilance by reducing agonistic behaviour. Vocal fish have been observed to emit sounds when predators approach or when being caught. However, none of the predators (or even conspecifics nearby) responded to these calls. Therefore, the term “predator-related” sound has been introduced in this paper to avoid implying unproven functions (alarm, startling, warning, distress and disturbance). Interestingly, the readiness of numerous taxa (e.g. catfishes) to vocalize when hand-held or netted was frequently exploited to investigate sound production in fish in relation to weight, sex, sonic organs, temperature or phylogeny. Increasing levels of noise in aquatic habitats call for more research on predator–prey interactions because of potential negative effects on detection of sounds produced by predators or prey.
... Diverse lineages of mammals and birds exhibit referential communication: signals refer to specific objects in the environment, and others receiving such signals respond accordingly, revealing that these listeners understand what is being signalled [1,2]. For example, referential alarm calls in most species studied alert conspecifics of specific predatory threats, such as aerial-hunting versus groundapproaching predators, and the signal alone is sufficient to elicit escape responses by conspecifics appropriate for the type of predator [3]. More rarely, referential alarm calls specifically denote the presence of a very different threat: obligate brood parasitic birds that lay their eggs in the nests of other species [1]. ...
Article
Yellow warblers ( Setophaga petechia ) use referential ‘seet’ calls to warn mates of brood parasitic brown-headed cowbirds ( Molothrus ater ). In response to seet calls during the day, female warblers swiftly move to sit tightly on their nests, which may prevent parasitism by physically blocking female cowbirds from inspecting and laying in the nest. However, cowbirds lay their eggs just prior to sunrise, not during daytime. We experimentally tested whether female warblers, warned by seet calls on one day, extend their anti-parasitic responses into the future by engaging in vigilance at sunrise on the next day, when parasitism may occur. As predicted, daytime seet call playbacks caused female warblers to leave their nests less often on the following morning, relative to playbacks of both their generic anti-predator calls and silent controls. Thus, referential calls do not only convey the identity or the type of threat at present but also elicit vigilance in the future to provide protection from threats during periods of heightened vulnerability.
... One of the most important roles of vocalization is to carry essential information about the environment, including foraging or signaling dangers. In vervet monkeys, alarm calls were identified as designating a specific type of predator (leopard, eagle and snake), and the behavioral responses following these calls were adapted to the type of predator (leopard alarm made the vervet monkeys run into trees, eagle alarm made them look up and snake alarms look down) (Seyfarth et al., 1980). Many non-human mammals are limited by small vocal repertoires, but a way to overcome this problematic is by combining calls (Arnold & Zuberbuhler, 2006). ...
Thesis
Investigating the fundamental cortical dynamics underlying vocal and speech production requires access to multiple cortical areas simultaneously. Such access is partly possible in humans when patients are implanted for clinical purpose with intracortical electrodes, but such cases are rare, with usually only partial coverage of involved brain areas. For this reason, animal models are useful to detail the dynamics of cortical networks underlying vocal production. To date, non-human primates, birds and recently rodents have been used, with increasing data showing that non-human primate network model of vocal production shares strong similarities with that of human speech production. The extent to which such model generalizes to other species remains however unclear. In this context, the main purpose of this thesis was to develop a novel experimental paradigm to investigate the cortical bases of vocal production using cortical electrode arrays in minipigs, a large non-primate species very keen in producing vocalizations and easy to handle by humans. This work was conducted in part within the frame of the Graphene Flagship aiming at developing low-noise cortical probes. Such implants were firstly tested in rats’ auditory cortex in response to pure sounds. To explore minipigs’ cortical bases of vocalizations, we firstly characterized the vocalizations produced by these animals in a housing pen, in a context similar to their daily life during the experiment. The results showed 6 categories of calls, with different occurrence situations and acoustic characteristics, allowing us to explore the vocal repertoire of minipigs. Secondly, we developed an experimental setup to record cortical activity along with vocalizations in freely behaving minipigs. We used three minipigs implanted in different cortical areas of the left hemisphere of the animals. We identified key regions activated during vocal production in minipigs, including motor and premotor cortices and inferior frontal gyrus. Minipigs are hence a promising model to study vocal production cortical networks.
... In our model, prey animals that start alarm calling because they hear enough of their neighbors' alarm calls subsequently approach those neighbors. In reality, prey animals, including primate species, may learn more information from the signal itself when listening to the call, for example because signalers may orient to the predator and therefore indicate its direction, or because different alarm calls referentially encode different types of threats (e.g., Cheney and Seyfarth, 1992;Crofoot, 2012;Digweed et al., 2005;Gursky-Doyen and Nekaris, 2007;Meno et al., 2013;Seyfarth et al., 1980bSeyfarth et al., , 1980aWheeler, 2008;Zuberbühler et al., 1999). It is, therefore, even more informative that signaling can increase other group members' survival rates by itself, even without signalers explicitly emitting additional information and without the receivers needing to see the predator themselves, as was the case in our model. ...
Article
Collective decision-making is a widespread phenomenon across organisms. Studying how animal societies make group decisions to the mutual benefit of group members, while avoiding exploitation by cheaters, can provide unique insights into the underlying cognitive mechanisms. As a step toward dissecting the proximate mechanisms that underpin collective decision-making across animals, we developed an agent-based model of antipredatory alarm signaling and mobbing during predator-prey encounters. Such collective behavior occurs in response to physical threats in many distantly related species with vastly different cognitive abilities, making it a broadly important model behavior. We systematically assessed under which quantitative contexts potential prey benefit from three basic strategies: predator detection, signaling about the predator (e.g., alarm calling), and retreating from vs. approaching the predator. Collective signaling increased survival rates over individual predator detection in several scenarios. Signaling sometimes led to fewer prey detecting the predator but this effect disappeared when prey animals that had seen the predator both signaled and approached it, as in mobbing. Critically, our results highlight that collective decision-making in response to a threat can emerge from simple rules without needing a central leader or needing to be under conscious control.
... F or many animals, including humans, social interactions often occur in group settings. These interactions are commonly mediated by vocal communication signals that convey social information, such as participant identity, context, and social preferences (1)(2)(3). Substantial progress has been made toward investigating the neural representation of sensory, motor, and social aspects of vocalizations separately (4)(5)(6)(7)(8), but rarely have all aspects been examined together (9) or in a group setting where behavioral and neural activity were recorded from more than two animals simultaneously. As a result, our ability to connect behavior and neural activity has been limited to individuals or pairs, rather than groups; consequently, it has been difficult to explore the specific social and neural relationships that exist within a group (10). ...
Article
Social interactions occur in group settings and are mediated by communication signals that are exchanged between individuals, often using vocalizations. The neural representation of group social communication remains largely unexplored. We conducted simultaneous wireless electrophysiological recordings from the frontal cortices of groups of Egyptian fruit bats engaged in both spontaneous and task-induced vocal interactions. We found that the activity of single neurons distinguished between vocalizations produced by self and by others, as well as among specific individuals. Coordinated neural activity among group members exhibited stable bidirectional interbrain correlation patterns specific to spontaneous communicative interactions. Tracking social and spatial arrangements within a group revealed a relationship between social preferences and intra- and interbrain activity patterns. Combined, these findings reveal a dedicated neural repertoire for group social communication within and across the brains of freely communicating groups of bats.
... Non-human primates (NHP) identify conspecific vocalizations (Rendall et al., 1996;Jovanovic et al., 2000;Ceugniet and Izumi, 2004;Belin, 2006) that inform troop members about food quality (Hauser, 1998;Slocombe and Zuberbühler, 2006) or nearby predators (Seyfarth et al., 1980b). These communication abilities are likely to rely on the activity of vocal recognition brain areas, homologous in humans and macaques Leaver and Rauschecker, 2010;Ortiz-Rios et al., 2015;Belin et al., 2018). ...
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In social animals, identifying sounds is critical for communication. In humans, the acoustic parameters involved in speech recognition, such as the formant frequencies derived from the resonance of the supralaryngeal vocal tract, have been well documented. However, how formants contribute to recognizing learned sounds in non-human primates remains unclear. To determine this, we trained two rhesus monkeys to discriminate target and non-target sounds presented in sequences of 1–3 sounds. After training, we performed three experiments: (1) We tested the monkeys’ accuracy and reaction times during the discrimination of various acoustic categories; (2) their ability to discriminate morphing sounds; and (3) their ability to identify sounds consisting of formant 1 (F1), formant 2 (F2), or F1 and F2 (F1F2) pass filters. Our results indicate that macaques can learn diverse sounds and discriminate from morphs and formants F1 and F2, suggesting that information from few acoustic parameters suffice for recognizing complex sounds. We anticipate that future neurophysiological experiments in this paradigm may help elucidate how formants contribute to the recognition of sounds.
... Much work on gestural meaning by field researchers has been used in the service of answering David Premack and Guy Woodruff 's (1978) early question: "Does the chimpanzee have a theory of mind?" Michael Tomasello and Josep Call (1997) have influentially answered this question in the negative, although they later redrew the dividing line not at a theory of mind, but rather at the use of a "perception-goal psychology as opposed to a humanlike belief-desire psychology" (Call and Tomasello 2008). After the conclusion of the great ape language debates, biological anthropologists largely resisted the question of whether nonhuman primates have a human-like capacity for language, instead turning their attention to how they communicate in their natural settings, within the larger context of their social behavior (for an early example, see Seyfarth, Cheney, and Marler 1980). Yet this fieldwork is again being placed into a dividing line by scholars distinguishing ape gestures from human gestures as owing "more to biology than learning" (Byrne and Cochet 2017). ...
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This article reviews accounts of “hugging” across evolutionary paradigms to expose how understandings of gesture are shaped by scientific theorizations of the ways humans and animals differ. The divergent roles assigned to gesture in human communication by Vygotskian and Chomskyan researchers can be traced to research on human exceptionalism during key historical periods in the Soviet Union and United States. When Vygotsky introduced his sociocultural theory of cognitive development during the early Soviet period, human exceptionalism was tested through reproductive crossbreeding. When Chomsky hypothesized a language acquisition device for the human brain during the Civil Rights era, human exceptionalism was tested through interspecies communication. These scientific histories inspired critically different approaches to gestural meaning. Taking a fresh look at the great ape language debates of the 1970s, the article attributes the dismissal of ethnography in late twentieth- century human language study to a developing experimental protocol that required gesture’s eviction. Access at: https://www.journals.uchicago.edu/doi/10.1086/715754
... For example, black-casqued hornbills respond more strongly to playbacks of crowned eagle (their main predator) than to vocalisations of leopard (a low-risk predator), and more strongly to playbacks of monkey alarm calls in response to eagles than monkey alarm calls in response to leopards (Rainey, Zuberbühler and Salter, 2004). Similarly, vervet monkeys give differing 'raptor', 'leopard' and 'snake' alarm calls, of which each promotes anti-predator behaviour appropriate to the predator (Seyfarth, Cheney and Marler, 1980;Price et al., 2015). In sub-Saharan Africa, the lion is the apex terrestrial carnivore, and prefers large prey (190 -550 kg) including Cape buffalo, zebra, giraffe and gemsbok . ...
Thesis
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Human-carnivore conflicts occur globally and are a leading cause of carnivore population declines. Such conflicts usually occur when carnivores predate livestock and can include preemptive and retaliatory killing of carnivores by livestock farmers. In northern Botswana, livestock farming is a widespread and culturally important practice. Subsistence farming enterprises commonly abut protected areas, and human-carnivore conflicts are common. Understanding interactions between livestock and carnivores, and how livestock use resources and habitats generally, are important components to managing these conflicts. Throughout this thesis, I explore human-carnivore conflict in northern Botswana. I found that livestock resource selection and predation vary seasonally and spatially in relation to ecological and anthropogenic features in the landscape. Predation sites are subsequently avoided by cattle in the short-term, but not by goats. Contemporary mitigation to minimise livestock predation events commonly includes lethal control and broadscale exclusion by artificial barriers and aversive interventions, yet naturally occurring deterrent signals fine-tuned through evolution are rarely considered. Lions roar to deter conspecifics from territorial boundaries, which prey and subordinate carnivores eavesdrop on and modify their movement and behaviour in response. I used lion vocalisations to understand livestock (prey) responses to this apex carnivore and to test how effective roars are in deterring lions and other carnivores. Using a high-tech experimental approach, I found that (1) cattle avoid lion vocalizations, while goats do not, and (2) lions are not deterred by lion roars played-back from Remotely Operated Acoustic Repellent stations (ROARs), nor are other human-carnivore conflict species occurring in the area. Finally, I used a commonly occurring anti-predator signal in nature, demonstrating that artificial eyespots painted on cattle rumps deter lions from attacking cattle. Collectively, the results from my thesis can be used to better manage livestock in a landscape of risk, and to promote human-carnivore coexistence by deterring predation. Applications derived from my thesis to promote human-carnivore coexistence can be used across Africa and the globe.
... 12 For example, the words 'cute' and 'dog' can compose to form the expression 'cute dog' in English; however, the meaning of this expression is determined trivially by the intersection of the sets 10 See, e.g., discussion in Hauser et al. (2002); Hauser and Fitch (2003); Mehler et al. (2006);Fitch (2010); Hurford (2012); Scott-Phillips and Blythe (2013); Berwick and Chomsky (2016). Of course, some non-human animals utilise remarkably complex communication systems-e.g., the combinatorial 'waggle dance' of Apis mellifera (Aristotle, 1995;Spitzner, 1788;von Frisch, 1967); the syntactic songs of Poecile atricapillus (Hailman et al., 1985); the 'pyow-hack' signals of Cercopithecus nictitans (Arnold and Zuberbühler, 2006a,b, 2008; or the functionally-referential alarm calls of Chlorocebus pygerythrus (Seyfarth et al., 1980b) and Cercopithecus diana (Zuberbühler et al., 1999), among others. Still, despite this remarkable variation and complexity, non-trivial (linguistic) compositionality appears to be unique to human-level linguistic communication systems. ...
Preprint
The value-alignment problem for artificial intelligence (AI) asks how we can ensure that the 'values' (i.e., objective functions) of artificial systems are aligned with the values of humanity. In this paper, I argue that linguistic communication (natural language) is a necessary condition for robust value alignment. I discuss the consequences that the truth of this claim would have for research programmes that attempt to ensure value alignment for AI systems; or, more loftily, designing robustly beneficial or ethical artificial agents.
... The investigation of meaning (or "semantics") in nonhuman animal vocalisation has played a central role in the field of animal communication since the foundational work on vervet monkey alarm calls (Seyfarth et al. 1980a(Seyfarth et al. , 1980b. The question and debate of what animal calls mean is still ongoing as shown by the recent discussions on the notion of functionally referential communication (e.g., Wheeler & Fischer 2012;Townsend et al. 2013) or the debates around the specificity of animal calls (Fichtel & Kappeler 2002;Schlenker et al. 2016b;Dezecache & Berthet 2018). ...
Article
The emergent field of animal linguistics applies linguistics tools to animal data in order to investigate potential linguistic-like properties of their communication. One of these tools is the “Urgency Principle”, a pragmatic principle stating that in an alarm sequence, calls providing information about the nature or location of a threat must come before those that do not. This theoretical principle has helped understand the alarm system of putty-nosed monkeys, but whether it is relevant for animal communication systems more generally remains to be tested. Moreover, while animal communication systems can convey information via a large set of encoding mechanisms, the Urgency Principle was developed for only one encoding mechanism, call ordering. Here, we propose to extend this principle to other encoding mechanisms and empirically test this with the alarm call system of black-fronted titi monkeys (Callicebus nigrifrons). We investigated how information about the context of emission unfolded with the emission of successive calls. Specifically, we analysed how contextual parameters influenced the gradual sequential organization of the first 50 calls in the sequence, using methods borrowed from computational linguistics and random forest algorithms. We hypothesized that, if the extended Urgency Principle reflected the sequential organization of titi monkey alarm call sequences, mechanisms encoding urgent information about the predatory situation should appear before encoding mechanisms that do not. Results supported the hypothesis that mechanisms encoding for urgent information relating to a predator event consistently appeared before mechanisms encoding for less-urgent social information. Our study suggests that the extended Urgency Principle applies more generally to animal communication, demonstrating that conceptual tools from linguistics can successfully be used to study nonhuman communication systems.
... An early example comes from authors Hayes & Hayes (1953), who studied picture and object symbol use in Viki the chimpanzee. Other work has evaluated the use of naturalistic symbolic communication, such as using predator calls in vervet monkeys (Seyfarth et al., 1980) and arbitrary symbol use (random icons) representing food and drink rewards for chimpanzees (Savage-Rumbaugh, 1986). In many cases, primates are able to acquire simple paired associations (e.g., "cup" picture = give cup). ...
Article
Symbol systems have a profound influence on human behavior, spanning countless modalities such as natural language, clothing styles, monetary systems, and gestural conventions (e.g., handshaking). Selective impairments in understanding and manipulating symbols are collectively known as asymbolia. Here we address open questions about the nature of asymbolia in the context of both historical and contemporary approaches to human symbolic cognition. We describe a tripartite perspective on symbolic cognition premised upon (1) mental representation of a concept, (2) a stored pool of symbols segregated from their respective referents, and (3) fast and accurate mapping between concepts and symbols. We present an open-source toolkit for assessing symbolic knowledge premised upon matching animated video depictions of abstract concepts to their corresponding verbal and nonverbal symbols. Animations include simple geometric shapes (e.g., filled circles, squares) moving in semantically meaningful ways. For example, a rectangle bending under the implied weight of a large square denotes “heaviness.” We report normative data for matching words and images to these target animations. In a second norming study, participants rated target animations across a range of semantic dimensions (e.g., valence, dominance). In a third study, we normed a set of concepts familiar to American English speakers but lacking verbal labels (e.g., the feeling of a Sunday evening). We describe how these tools may be used to assess human symbolic processing and identify asymbolic deficits across the span of human development.
... On the face of it, this apparently corrective behavior seems to allow young members of the group to improve their performance 10 (see e.g. Cheney & Seyfarth 1980). Moreover, the behavior of plants or heatseeking missiles is clearly far outstripped both in complexity and unpredictability by the behavior of vervet monkeys and many other creatures, and therefore they should not be judged on the same basis. ...
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In a couple of short papers, Donald Davidson holds that a creature cannot think unless it is the interpreter of the speech of another. At first blush, speaking a language is, therefore, a necessary condition for thought. His controversial claims has led many to regard him as a follower of the Cartesian tradition wherein languageless creatures are nothing but mindless machines. Against this widely shared interpretation, in this paper we put forward a more charitable interpretation of Davidson’s claims. According to our reading, Davidson never meant to argue that languageless creatures do not think. Instead, the only thing his arguments purport to show is that one will never be in a position to confirm that they do. This paper consists of a defense of the idea that Davidson is better seen as endorsing radical skepticism as to whether languageless creatures think.
... We have known for a few decades that primates, and here we specifically refer to free-ranging East African vervet monkeys, Chlorocebus pygerythrus, have different alarm calls for different predators. A call for an eagle is distinct from a call for a leopard, among other threats and predators (Seyfarth et al., 1980). In the end, hiding from an eagle is different than hiding from a leopard. ...
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The intent of this article is to show that speech sounds can be much more than mere meaning-distinguishing units. Through established cross-modal correspondences with other sensory dimensions, human vocalizations can bear meaning that translates to a real-world context. We argue that cross-modal correspondences and the iconic resemblance between the audible form of spoken language and other sensory information create meaning and were essential to get language off the ground at its dawn. In this sense, the world of sounds can be full of meaning.
... On the other hand, there is evidence in some cases that animal calls can be functionally referential, reliably Frontiers in Psychology | www.frontiersin.org co-occurring with external entities (Seyfarth et al., 1980;Price et al., 2015), but little evidence that complex vocalisations like bird song or whale song have functional referential meaning (Engesser and Townsend, 2019). Analysing information trajectories across multiple levels of the sequence might give additional insight into this important question, but this requires that several such levels can be disentangled in the first place, which might not be easily the case in animal vocalisations. ...
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Music and spoken language share certain characteristics: both consist of sequences of acoustic elements that are combinatorically combined, and these elements partition the same continuous acoustic dimensions (frequency, formant space and duration). However, the resulting categories differ sharply: scale tones and note durations of small integer ratios appear in music, while speech uses phonemes, lexical tone, and non-isochronous durations. Why did music and language diverge into the two systems we have today, differing in these specific features? We propose a framework based on information theory and a reverse-engineering perspective, suggesting that design features of music and language are a response to their differential deployment along three different continuous dimensions. These include the familiar propositional-aesthetic (‘goal’) and repetitive-novel (‘novelty’) dimensions, and a dialogic-choric (‘interactivity’) dimension that is our focus here. Specifically, we hypothesize that music exhibits specializations enhancing coherent production by several individuals concurrently—the ‘choric’ context. In contrast, language is specialized for exchange in tightly coordinated turn-taking—‘dialogic’ contexts. We examine the evidence for our framework, both from humans and non-human animals, and conclude that many proposed design features of music and language follow naturally from their use in distinct dialogic and choric communicative contexts. Furthermore, the hybrid nature of intermediate systems like poetry, chant, or solo lament follows from their deployment in the less typical interactive context.
... For instance, Mann 14 found that over half of all cetacean studies in their review used ad libitum sampling, even though such sampling methods are recognized to be both less quantitative and systematic. Likewise, one-zero sampling methods are typically used by primatologists and behaviour analysts for the study of non-human primate and human behaviour, respectively [30][31][32][33][34][35][36]49,[53][54][55][56][57] . The concept of using methodology passed down from previous studies and labs has been referred to as "laboratory lore" and is an asset to the cultural transmission of scientific knowledge 58,59 . ...
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Behavioural research requires the use of sampling methods to document the occurrence of responses observed. Sampling/recording methods include ad libitum, continuous, pinpoint (instantaneous), and one-zero (interval) sampling. Researchers have questioned the utility of each sampling method under different contexts. Our study compared computerized simulations of both pinpoint and one-zero sampling to continuous recordings. Two separate computer simulations were generated, one for response frequency and one for response duration, with three different response frequencies (high, medium, or low) and response durations (short, medium, and long) in each simulation, respectively. Similarly, three different observation intervals (5, 50, and 500 s) were used to record responses as both pinpoint and one-zero sampling methods in the simulations. Under both simulations, pinpoint sampling outperformed one-zero sampling, with pinpoint sampling producing less statistical bias in error rates under all frequencies, durations, and observation intervals. As observation intervals increased, both mean error rates and variability in error rates increased for one-zero sampling, while only variability in error rate increased for pinpoint sampling. The results suggest that pinpoint sampling techniques are effective for measuring both frequency (event) and duration (state) behaviours, and that pinpoint sampling is a less statistically biased behavioural observation method than one-zero sampling.
... Des vocalisations spécifiques peuvent ainsi faire référence à des éléments extérieurs comme un type de prédateur (e.g. chez les vervets, Chlorocebus pygerythrus, et les mones de Campbell, Cercopithecus campbelli : Seyfarth et al. 1980;Seyfarth et Cheney 2003;Ouattara et al. 2009) ou un type d'aliment (e.g. chez les chimpanzés : Slocombe et Zuberbühler 2005). ...
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Ce travail s’inscrit dans l’étude des origines évolutives du langage, par la recherche de propriétés langagières dans la communication gestuelle et multimodale de primates cercopithécidés en captivité, les mangabeys à collier. Par une double approche observationnelle et expérimentale, nous avons montré que les gestes des mangabeys remplissent les critères de définition d’une communication intentionnelle, et peuvent être produits de manière flexible dans différents contextes. Nos observations fournissent également de premiers éléments en faveur d’une intentionnalité des expressions faciales des cercopithécidés, souvent considérées comme de simples indices d’état émotionnel. Cette propriété sociocognitive langagière pourrait ainsi être plus ancienne que ce que nous pensions dans l’histoire évolutive des primates, et être héritée de la communication gestuelle des ancêtres des catarrhiniens, il y a environ 29 millions d’années. De plus, nous avons mis en évidence un effet significatif du contexte interactionnel sur la latéralité gestuelle des mangabeys, suggérant une importance particulière de facteurs sociaux dans l’émergence d’une spécialisation hémisphérique pour la communication intentionnelle, dont le langage humain. Enfin, par une méthode originale, reposant sur des analyses de séquences et de réseau, nous avons décrit la communication multimodale et multicomposante des mangabeys à collier, et montré qu’ils combinent de manière flexible différents types et modalités de signaux en fonction du contexte et de facteurs sociodémographiques. Nos résultats soulignent l’importance d’une approche multimodale pour comprendre la complexité de la communication des primates, et apportent de premier éléments de compréhension sur la fonction des combinaisons de signaux. De futures comparaisons à d’autres espèces et dans différents environnements pourraient permettre d’affiner nos connaissances quant aux possibles contraintes évolutives ayant favorisé une telle complexité de la communication des primates humains et non-humains.
... This approach is similar to that taken to understand communication behaviour in animals. For example, researchers might categorize the calls of vervet monkeys according to their use in the context of a snake or an eagle 66 without making claims about the cognitive mechanisms involved. This approach was dominant in many early social interaction studies 29,67 , which catalogued different types of movement and assigned likely meanings to them 28,68 . ...
Article
For most of human history, face-to-face interactions have been the primary and most fundamental way to build social relationships, and even in the digital era they remain the basis of our closest bonds. These interactions are built on the dynamic integration and coordination of verbal and non-verbal information between multiple people. However, the psychological processes underlying face-to-face interaction remain difficult to study. In this Review, we discuss three ways the multimodal phenomena underlying face-to-face social interaction can be organized to provide a solid basis for theory development. Next, we review three types of theory of social interaction: theories that focus on the social meaning of actions, theories that explain actions in terms of simple behaviour rules and theories that rely on rich cognitive models of the internal states of others. Finally, we address how different methods can be used to distinguish between theories, showcasing new approaches and outlining important directions for future research. Advances in how face-to-face social interaction can be studied, combined with a renewed focus on cognitive theories, could lead to a renaissance in social interaction research and advance scientific understanding of face-to-face interaction and its underlying cognitive foundations.
... Sound categories can be validated through studies of categorical perception (Ehret 1987;Harnad 1987;Nelson and Marler 1989;Fischer 1998;Baugh et al. 2008;Green et al. 2020) or by demonstrating a specific differential usage of calls relative to surrounding conditions (e.g. Seyfarth et al. 1980) or features of the sender (e.g. Janik 1999). ...
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Stemming from the traditional use of field observers to score states and events, the study of animal behaviour often relies on analyses of discrete behavioural categories. Many studies of acoustic communication record sequences of animal sounds, classify vocalizations, and then examine how call categories are used relative to behavioural states and events. However, acoustic parameters can also convey information independent of call type, offering complementary study approaches to call classifications. Animal-attached tags can continuously sample high-resolution behavioural data on sounds and movements, which enables testing how acoustic parameters of signals relate to parameters of animal motion. Here, we present this approach through case studies on wild common bottlenose dolphins ( Tursiops truncatus ). Using data from sound-and-movement recording tags deployed in Sarasota (FL), we parameterized dolphin vocalizations and motion to investigate how senders and receivers modified movement parameters (including vectorial dynamic body acceleration, “VeDBA”, a proxy for activity intensity) as a function of signal parameters. We show that (1) VeDBA of one female during consortships had a negative relationship with centroid frequency of male calls, matching predictions about agonistic interactions based on motivation-structural rules; (2) VeDBA of four males had a positive relationship with modulation rate of their pulsed vocalizations, confirming predictions that click-repetition rate of these calls increases with agonism intensity. Tags offer opportunities to study animal behaviour through analyses of continuously sampled quantitative parameters, which can complement traditional methods and facilitate research replication. Our case studies illustrate the value of this approach to investigate communicative roles of acoustic parameter changes. Significance statement Studies of animal behaviour have traditionally relied on classification of behavioural patterns and analyses of discrete behavioural categories. Today, technologies such as animal-attached tags enable novel approaches, facilitating the use of quantitative metrics to characterize behaviour. In the field of acoustic communication, researchers typically classify vocalizations and examine usage of call categories. Through case studies of bottlenose dolphin social interactions, we present here a novel tag-based complementary approach. We used high-resolution tag data to parameterize dolphin sounds and motion, and we applied continuously sampled parameters to examine how individual dolphins responded to conspecifics’ signals and moved while producing sounds. Activity intensity of senders and receivers changed with specific call parameters, matching our predictions and illustrating the value of our approach to test communicative roles of acoustic parameter changes. Parametric approaches can complement traditional methods for animal behaviour and facilitate research replication.
Article
This paper explores the significance of intelligent social behavior among non‐human animals for philosophical theories of communication. Using the alarm call system of vervet monkeys as a case study, I argue that interpersonal communication (or what I call “minded communication”) can and does take place in the absence of the production and recognition of communicative intentions. More generally, I argue that evolutionary theory provides good reasons for maintaining that minded communication is both temporally and explanatorily prior to the use of communicative intentions. After developing these negative points about the place of communicative intentions in detail, I provide a novel alternative account according to which minded communication is characterized in terms of patterns of action and response that function to coordinate the representational mental states of agents. I show that an account which centers on patterns of representational coordination of this sort is well suited to capture the theoretical roles associated with minded communication and that it does so in a way that provides a good fit with comparative facts about the presence of minded communication among non‐human animals.
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Machine learning has been advancing dramatically over the past decade. Most strides are human-based applications due to the availability of large-scale datasets, however, opportunities are ripe to apply this technology to more deeply understand non-human communication. We detail a scientific roadmap for advancing the understanding of communication of whales that can be built further upon as a template to decipher other forms of animal and non-human communication. Sperm whales, with their highly-developed neuroanatomical features, cognitive abilities, social structures, and discrete click-based encoding make for an excellent model for advanced tools that can be applied to other animals in the future. We outline the key elements required for the collection and processing of massive datasets, detecting basic communication units and language-like higher-level structures, and validating models through interactive playback experiments. The technological capabilities developed by such an undertaking hold potential for cross-applications in broader communities investigating non-human communication and behavioral research.
Thesis
La grégarité compte parmi les phénomènes les plus communs du vivant et produit à son tour des phénoménologies parmi les plus impressionnantes observables dans le monde. Chez plusieurs espèces animales, des structures complexes émergent, alors qu'elles semblent à priori inaccessibles à l'échelle individuelle comme les formes spectaculaires prises par les bancs de sardines ou les étourneaux. De nombreux travaux sont dédiés à l'étude des déplacements collectifs et cherchent à comprendre comment des interactions locales permettent l'émergence de fonctionnements et structures complexes des groupements. La simple mise en mouvement d'un groupe nécessite coordination et transfert d'information rapide pour répondre aux contraintes environnementales et ainsi conserver l'intégrité du groupe. De nombreux mécanismes sont proposés dans la littérature pour rendre compte des règles d'interactions qui permettent de tels phénomènes. Bien souvent, ce sont des forces sociales qui sont utilisées et les modèles qui les utilisent ont prouvé leur robustesse dans la reproduction de ces phénomènes. Il me semble cependant qu'au niveau conceptuel, assimiler des interactions sociales à des forces présente de nombreuses limites notamment dans la prise en compte de comportements intermittents. J'ai dans ce travail de thèse investigué l'apport d'une hypothèse alternative basée sur des transitions probabilistes entre des états comportementaux. Nous avons dans un premier temps approfondi une étude expérimentale réalisée dans l'équipe permettant de mettre en lumière la constitution du voisinage influent, prérequis nécessaire à la formation d'interactions. Nous avons notamment pu rendre compte de la possibilité que les interactions dépendent de la distance. Dans un deuxième temps, nous avons construit un modèle individu-centré, modélisant la dynamique de transition entre stationnarité et départ collectif, en une puis deux dimensions. Nous avons quantifié la propagation d'une information, le départ d'un individu, dont la nature très particulière lui permet de rétroagir sur sa propre propagation. Nous avons ainsi révélé une phénoménologie très diverse, dépendante de la vitesse de déplacement des individus qui est un paramètre du système. Nous avons également pu mettre en lumière des propriétés de criticalité très affectées par les fluctuations liées à la stochasticité des transitions. Par ailleurs, nous avons construit un système d'équations aux dérivées partielles en support des simulations réalisées. Ce système a permis d'une part, de démontrer mathématiquement des propriétés et phénoménologies produites par les simulations, mais aussi de faire un parallèle conceptuel avec des équations de réaction-diffusion de type Fisher-Kolmogorov-Petrovskii-Piskunov. Enfin nous avons démontré dans une dernière étude que notre modèle était capable de conserver l'intégrité du groupe en dépit de l'absence d'une force explicite d'attraction. Cela nous a permis à la fois de définir ce qu'était la cohésion d'un groupe, et de quantifier une partie de ces caractéristiques. Nous avons finalement réussi à donner un modèle minimal qui permet la conservation de la cohésion du groupe.
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Pair-bonding allows for division of labor across behavioral tasks such as protecting a territory, caring for pups or foraging for food. However, how these labor divisions are determined, whether they are simply intrinsic differences in the individual’s behavior or a coordinated behavioral response by the pair, remains unknown. We used the monogamous, biparental and territorial California mouse ( Peromyscus californicus ) to study how behavioral approach to an aggressive vocal stimulus in a novel environment was affected by pair-bonding. Using a three-chambered vocal playback paradigm, we first measured the amount of time individuals spent in close proximity to aggressive bark vocalizations. We found that animals could be categorized as either approachers or avoiders. We then paired individuals based on their initial approach behavior to an opposite sex individual who displayed either similar or different approach behaviors. These pairs were then retested for approach behavior as a dyad 10–11 days post-pairing. This test found that pairs showed convergence in their behavioral responses, such that pairs who were mismatched in their approach behaviors became more similar, and pairs that were matched remained so. Finally, we analyzed the ultrasonic vocalizations (USV) produced and found that pairs produced significantly more USVs than individuals. Importantly, increased USV production correlated with increasing behavioral convergence of pairs. Taken together, this study shows that pair-bonded animals alter their approach behaviors to coordinate their response with their partner and that vocal communication may play a role in coordinating these behavioral responses. Overall, our findings indicate that pair-bonding generates an emergent property in pairs, adjusting their combined approach behavior towards a new aggressive stimulus representing a potential challenge to the bonded pair. Such findings may be broadly important for social bonding in other social systems.
Article
A fundamental aspect of human communication is our ability to refer to external objects and events through both words and gestures (such as pointing), yet the evolutionary origins of such signals remain obscure. Apes, living in their natural environments, rarely or never point, but it has been claimed that male chimpanzees, Pan troglodytes schweinfurthii, from the Ngogo community, Uganda, habitually use exaggerated loud scratches (ELSs) to refer to specific body locations where they wish to be groomed (Pika & Mitani, 2006, Current Biology, 16(6), 191–192). This study suggested continuity between referential abilities in humans and our closest living relatives, making it an important finding to replicate in other populations. Hence here, we compared whether ELSs are used in a referential manner across four wild communities of eastern chimpanzees (Ngogo, Kanyawara, Sonso and Waibira). Our data show that scratchers were significantly more likely to receive grooming in the scratched location at Ngogo compared to the other three sites. At the latter sites this response occurred at low rates and signallers did not seem to pursue this goal. This suggests that ELSs do not function referentially at these sites, and the published findings from Ngogo were not replicated. Further exploration into alternative functions of ELSs in the Kanyawara community revealed that, in this community, this signal functions to initiate grooming bouts and to reengage partners during grooming pauses. Individuals who produced the signal to initiate grooming were likely to offer grooming. In contrast, during grooming bouts, groomers produced ELSs to request reciprocation of grooming from their partner. Our study demonstrates that chimpanzees do not ubiquitously use the ELS in a referential manner, but that they can use this gesture in a highly flexible fashion, with signal function depending on the intricate details of the social contexts in which they are produced.
Article
Animal learning theory has been enormously influential in setting up laws of how individuals gradually learn associations and instrumentation by reinforcement. Yet, the theory rests on data collected from socially isolated laboratory animals, exposed to artificial cause–effect relations without visible agents. We review the primate vocal learning literature and find that animal learning theory performs poorly in accounting for real-life learning and evolutionarily relevant problem-solving. Instead, learning occurs when conspecifics act as event-causing agents, often without direct consequences for learners. We illustrate this with recent field studies, which suggest that the default mode of learning may not be through reinforcement and repeated trials but by acquiring scripts — mental representations of how events typically unfold. Becoming communicatively competent may be more about learning how events unfold than becoming conditioned to stimuli and responses.
Thesis
L’universalité des “règles” qui régissent les conversations humaines, comme le respect du tour de parole, suggère de possibles bases biologiques à ce comportement. Au travers d’une revue de la littérature, nous avons révélé qu’à l’image de nos conversations, les échanges vocaux de vocalisations de contact de la plupart des primates non-humains respectent des règles sociales et temporelles. Notamment, les interlocuteurs, choisis sur des critères sociaux, alternent leurs émissions vocales tout en évitant de se couper la parole. Ces échanges permettent de créer et consolider des relations affiliatives. Toutefois, les grands singes sont peu représentés dans la littérature disponible sur ce sujet, malgré l’intérêt comparatif qu’ils représentent de par leur proximité phylogénétique avec l’humain et la diversité de leurs systèmes sociaux. Ce projet vise donc à décrire les règles d’interactions vocales chez les grands singes non-humains : bonobos (Pan paniscus), chimpanzés (Pan troglodytes), gorilles des plaines de l’Ouest (Gorilla gorilla gorilla) et orangs-outans de Bornéo (Pongo pygmaeus). Dans un premier temps, une approche expérimentale a permis de vérifier l’importance du respect du tour de parole lors des échanges vocaux pour les gorilles et de souligner un rôle possible de l’apprentissage social dans l’acquisition des règles appropriées d’interaction. Ensuite, une approche observationnelle menée sur un groupe de chimpanzés captifs a, au contraire, souligné l’extrême rareté des tours de paroles, au profit d’interactions vocales de type chorus et de fréquentes émissions de cris isolés associées à la régulation des conflits. Enfin, une approche comparative des quatre espèces, mêlant des données provenant de la littérature à nos propres résultats, a suggéré que l’organisation temporelle des interactions vocales est sous l’influence de caractéristiques sociales telles que le degré de socialité et de tolérance intra-groupe, comme le souligne l’existence d’échanges vocaux organisés chez les gorilles et les bonobos. La découverte d’échanges vocaux organisés chez les grands singes permet de compléter l’arbre phylogénétique de cette capacité langagière. Des investigations comparatives supplémentaires restent à mener afin d’affiner nos connaissances quant aux multiples et subtils facteurs sociaux ayant favorisé l’émergence de ce comportement interactionnel.
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Deciphering nonhuman communication – particularly nonhuman vocal communication – has been a longstanding human quest. We are, for example, fascinated by the songs of birds and whales, the grunts of apes, the barks of dogs, and the croaks of frogs; we wonder about their potential meaning and their relationship to human language. Do these utterances express little more than emotional states, or do they convey actual bits and bytes of concrete information? Humans’ numerous attempts to decipher nonhuman systems have, however, progressed slowly. We still wonder why only a small number of species are capable of vocal learning, a trait that, because it allows for innovation and adaptation, would seem to be a prerequisite for most language-like abilities. Humans have also attempted to teach nonhumans elements of our system, using both vocal and nonvocal systems. The rationale for such training is that the extent of success in instilling symbolic reference provides some evidence for, at the very least, the cognitive underpinnings of parallels between human and nonhuman communication systems. However, separating acquisition of reference from simple object-label association is not a simple matter, as reference begins with such associations, and the point at which true reference emerges is not always obvious. I begin by discussing these points and questions, predominantly from the viewpoint of someone studying avian abilities. I end by examining the question posed by Premack: do nonhumans that have achieved some level of symbolic reference then process information differently from those that have not? I suggest the answer is likely “yes,” giving examples from my research on Grey parrots (Psittacus erithacus).
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This meta-study of animal semantics is anchored in two claims, seemingly creating a fuzzy mismatch, that animal utterances generally appear to be simple in structure and content variation and that animals’ communicative understanding seems disproportionally more advanced. A set of excerpted, new studies is chosen as basis to discuss whether the semantics of animal uttering and understanding can be fused into one. Studies are prioritised due to their relatively complex designs, giving priority to dynamics between syntax, semantics, pragmatics, and between utterers and receivers in context. A communicational framework based on utterance theory is applied as a lens for inspection of how these aspects relate to the assumed mismatch. Inspection and discussions of the studies bring several features to surface of which five are stressed in the following. Firstly, both syntactic structures and possible semantic content are seen as lean, although richer than earlier believed, and research continues to reveal new complexities in utterances. Secondly, there is a clear willingness to broaden the perception of animals’ semantic capacity to comprehend communication both by arguing theoretically and by generating empirical research in new contexts. Thirdly, the ambition to make sense of these tendencies is still often motivated by an evolutionary search for early building blocks for verbal language, with the pro et cons that such a position can have. Fourthly, the ‘allowed’ scientific frame for studying semantic capacity among animals is extended to new fields and contexts challenging the only-in-the-wild norm. Fifthly, the dilemma of integrating uttering and understanding as aspects of an after all functional communicational system, calls for new epistemological concepts to make sense of the claimed mismatch. Affordances , abduction , life-genre , and lifeworld are suggested.
Chapter
This chapter is concerned primarily with evidence that focuses on the nature and usage of knowledge. The experimental work of animal behavior researchers is devoted to determining the properties of the mental structures of other animals and discovering how they function, regardless of whether or not the animal is aware. Oscillators or central pattern generators are another class of central behavior mechanisms. Memory is the representation of past experience and can be considered a process leading to the formation of behavior mechanisms as well as the outcome of the process. Cognitive psychologists who study memory are interested in the relations among the acquisition, retention, and retrieval mechanisms of memory. Orientation is generally considered to be a change of an organism's position in space as a response to an external stimulus. Social learning refers to any learning that is influenced by interaction with, or observation of, another animal or its products.
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The social complexity hypothesis (SCH) for communication states that the range and frequency of social interactions drive the evolution of complex communication systems. Surprisingly, few studies have empirically tested the SHC for vocal communication systems. Filling this gap is important because a co-evolutionary runaway process between social and vocal complexity may have shaped the most intricate communication system, human language. We here propose the African elephant Loxodonta spec. as an excellent study system to investigate the relationships between social and vocal complexity. We review how the distinct differences in social complexity between the two species of African elephants, the forest elephant L. cyclotis and the savanna elephant L. africana, relate to repertoire size and structure, as well as complex communication skills in the two species, such as call combination or intentional formant modulation including the trunk. Our findings suggest that Loxodonta may contradict the SCH, as well as other factors put forth to explain patterns of vocal complexity across species. We propose that life history traits, a factor that has gained little attention as a driver of vocal complexity, and the extensive parental care associated with a uniquely low and slow reproductive rate, may have led to the emergence of pronounced vocal complexity in the forest elephant despite their less complex social system compared to the savanna elephant. Conclusions must be drawn cautiously, however. A better understanding of vocal complexity in the genus Loxodonta will depend on continuing advancements in remote data collection technologies to overcome the challenges of observing forest elephants in their dense rainforest habitat, as well as the availability of directly comparable data and methods, quantifying both structural and contextual variability in the production of rumbles and other vocalizations in both species of African elephants.
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Este trabajo efectúa un análisis crítico del libro Animal languages, escrito por la filósofa holandesa Eva Meijer. La intención de la autora es mostrar que los animales tienen destrezas cognitivas y comunicativas complejas, pero su estrategia vincula esa complejidad comunicativa con el carácter lingüístico de los códigos comunicativos animales. Más allá de sostener que los animales tienen lenguaje (algo frecuente en etólogos), la obra deja mucho que desear desde la óptica científica. El trabajo mostrará que el libro de Meijer está repleto de contradicciones, exageraciones, afirmaciones extravagantes o infundadas, tergiversaciones de la opinión de otros autores, errores en el uso de referencias bibliográficas o desconocimientos muy graves de diferentes aspectos.
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The question of whether sociologists should investigate the subjective experience of non-human others arises regularly in discussions of research on animals. Recent criticism of this research agenda as speculative and therefore unproductive is examined and found wanting. Ample evidence indicates that animals have the capacity to see themselves as objects, which meets sociological criteria for selfhood. Resistance to this possibility highlights the discipline’s entrenched anthropocentrism rather than lack of evidence. Sociological study of the moral status of animals, based on the presence of the self, is warranted because our treatment of animals is connected with numerous “mainstream” sociological issues. As knowledge has brought other forms of oppression to light, it has also helped to challenge and transform oppressive conditions. Consequently, sociologists have an obligation to challenge speciesism as part of a larger system of oppression.
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Recent discoveries of semantic compositionality in Japanese tits have enlivened the discussions on the presence of this phenomenon in wild animal communication. Data on semantic compositionality in wild apes are lacking, even though language experiments with captive apes have demonstrated they are capable of semantic compositionality. In this paper, I revisit the study by Boesch (Hum. Evol. 6:81–89, 1991) who investigated drumming sequences by an alpha male in a chimpanzee ( Pan troglodytes ) community in the Taï National Park, Côte d’Ivoire. A reanalysis of the data reveals that the alpha male produced semantically compositional combined messages of travel direction change and resting period initiation. Unlike the Japanese tits, the elements of the compositional expression were not simply juxtaposed but displayed structural reduction, while one of the two elements in the expression coded the meanings of both elements. These processes show relative resemblance to blending and fusion in human languages. Also unlike the tits, the elements of the compositional expression did not have a fixed order, although there was a fixed distribution of drumming events across the trees used for drumming. Because the elements of the expression appear to carry verb-like meanings, the compositional expression also resembles simple verb-verb constructions and short paratactic combinations of two clauses found across languages. In conclusion, the reanalysis suggests that semantic compositionality and phenomena resembling paratactic combinations of two clauses might have been present in the communication of the last common ancestor of chimpanzees and humans, not necessarily in the vocal modality.
Article
Despite ongoing research, many aspects of dogs’ vocal communication are not yet fully understood, including how they convey information about items. The aim of the present exploratory study was to determine whether dogs vocalize differently toward their owner and food in an unsolvable task where food is inaccessible and to characterize the acoustic composition of canine vocalizations. In Savalli et al. (2014; 2016), food was placed in an inaccessible location with the dog present. Next, with the owner present, the communicative modalities of the dogs were recorded, including their vocalizations. Only 21.6% of the fifty-one dogs vocalized (11 dogs out of 51; 189 vocalizations); 32.27% of the vocalizations were whines and whine-related, and 67.72% were barks and bark-related. Vocalizations may thus be a secondary modality of communication or, more likely, most of the dogs had previously learned from their owners not to vocalize in food-request situations by lack of reinforcement. We characterized four types of whines and five types of barks, respectively making up 1/3 and 2/3 of the vocalizations recorded. No other type of vocalization was found. We found firstly that the majority of the vocalizations (67.7%) were directed at the owner. Secondly, whines were rarely directed at food. Thirdly, though fundamental frequency (F0) and duration did not statistically differ for each type of vocalization, whether directed at the target or at the owner, we found a tendency of specific sub-unit of a bark to have a higher F0 and lower duration when dogs gazed at the target compared when the gazed at the owner. This type of vocalizations was thus not used similarly according to the target viewed, indicating that dogs employ different types of vocal coding to call for attention. Given the small number of dogs who vocalized in this study, future studies will involve a larger group of dogs who will be tested outdoors with an inaccessible toy to enable more vocalizations. This exploratory study opens perspectives in understanding needs expressed by dogs.
Article
Prey species must often face a trade‐off between acquiring resources and minimizing predation risk. The spatial variation in predation risk across a landscape, as perceived by prey across their foraging or home range, creates a “landscape of fear” by which individuals modify their behavior in response to the level of perceived risk. Here, we explored the influence of perceived predation risk, habitat features associated with risk, and fruit availability, on the spatial variation in behavior of the endangered forest‐dwelling samango monkey (Cercopithecus albogularis schwarzi). We collected behavioral and location data on two habituated samango monkey groups in the Soutpansberg Mountains, South Africa, between 2012 and 2016. We further collected location data of the samango monkey's acoustically distinct alarm call, which has an unambiguous association with aerial predators, to spatially map perceived risk across the landscape. Using generalized linear mixed models, we found that perceived risk from eagles significantly influenced the spatial distribution of critical life‐functioning behaviors, with samango monkeys increasing feeding and foraging in high‐risk areas. To mitigate this risk, samangos increased cohesion between group members, which subsequently reduced vigilance levels. Group cohesion further increased in high‐risk areas with abundant fruit, relative to high‐risk, fruit‐poor areas, demonstrating the monkey's foraging/risk trade‐off. Feeding was also reduced in areas of low canopy height, while vigilance decreased with increasing understory visibility and distance from sleep site, showing the influence of landscape features on risk perception from other predator guilds. Thus, for arboreal species foraging in a 3‐D landscape, risk perception may occur at multiple scales and in response to multiple predator guilds. Only moving was influenced by fruit availability, either due to moving between localized food patches or from escaping high‐risk areas following feeding bouts. These findings highlight that risk‐taking in samango monkeys is only associated with behaviors fundamental to survival at a given location and that increased cohesion between neighbors is the main antipredator response in this species.
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Communication is the transmission of information from one animal to another. Although communication can be as complex as any set of words ever put on paper, it can also be as simple as a receptor sensing a molecule emitted from another living organism. Indeed, such receptors are hypothesized to be the evolutionary antecedent of communication. From that point onward, communication has evolved to use a variety of modes, including chemical, visual, auditory, tactile, and more. The world of communication that behavioral studies reveal ranges from warning coloration to infrasonic elephant communication to electrical pulses and poses a challenge: what signals do animals use that are beyond human sensory ability?
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I read with great interest the study by Leroux et al. [(2021) Anim Behav 179, 41–50] who investigated the nature of pant-hoot–food-call combinations in a community of wild chimpanzees (Pan troglodytes schweinfurthii) at the Budongo Conservation Field Station, Budongo Forest, Uganda. The authors propose, among others, that they reveal the first evidence that wild chimpanzees are able “to combine meaning-bearing units into larger structures” – i.e., that they are capable of semantic compositionality and, by extension, syntax. Their analysis represents an important addition to a growing body of research and discussions on communicational combinatoriality in wild primates and specifically apes, and, by extension, extinct hominins. Incidentally, I have recently published a paper in Animal Cognition in which I also suggested, based on a reanalysis of existing data, that wild chimpanzees can display semantic compositionality and syntax, i.e., are able to combine meaningful units [Gabrić (2021) Anim Cogn, online ahead of print]. In the present commentary, I argue that Leroux et al.’s (2021) interpretation of the data is ungrounded given that (1) unlike for food calls, there is currently very little if any indication in the scientific literature that pant-hoots have semantic content, i.e., are meaningful, (2) Leroux et al. (2021) did not investigate their a priori assumption that the observed pant-hoots are in fact meaningful/semantic, (3) they did not report on recipients’ behaviors in association with neither the individual nor combined calls, and (4) they did not compare the callers’ behaviours in association with the individual calls vs. combined calls. Since pant-hoots feature prominently in the chimpanzee vocal repertoire and the debate on their eventual meaningfulness/semanticity is still wide open, this represents a fine opportunity to revisit this issue in the context of Leroux et al.’s (2021) study. Their paper further raises several other less significant questions. Notwithstanding, their paper brings important novel insights into communicational combinatoriality in wild chimpanzees and supports the notion of using linguistic methods in wild animal communication research.
Article
A founder of the fields of behavioural ecology and neuroethology, Peter Marler’s research uncovered fundamental principles underlying how animals learn to communicate and employ signals in numerous contexts. Studying animal taxa as diverse as birds and primates, he helped illuminate how general principles underlie the communication of all animals. Further, he illustrated the power of comparative research to help us learn more about human behaviour and language. His approach shows us the importance of careful, curiosity-driven research inspired by natural history. Here, I discuss some of Peter Marler’s influential research findings and their impact on modern research in animal behaviour.
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This chapter provides an overview how evolutionary theory has been applied to investigate human behavior and cognition, examining whether human beings can be studied in the same way as any other species of animal. It reviews the history of applying evolutionary theory to human behavior from C. Darwin to the present day, highlighting recurrent controversies such as the "nature versus nurture" debate. The chapter evaluates the assumption that human beings can be studied as if they were any other animal species. Human beings are potentially different from other animals in terms of their reliance on culture and the extent to which human beings modify their selective environments, and the fidelity, efficiency, and breadth of information transfer, which is enhanced by language and teaching. Human language allows for trade, a form of mutualistic exchange that outside of humans is virtually absent in the animal kingdom.
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Many of the most spectacular and beautiful traits of animals function in communication. A second focus will be the relationship between animal communication and human language. Human language is far more complex and cognitively sophisticated than the communication system of any non-human animal. Signal reliability is an important issue for any communication system that is informational. Signals subject to a physical constraint are termed index signals and are often considered to be inherently honest because of an inescapable relationship between a signal feature and the physical characteristics of the signaler. The best known hypothesis for how signal costs can produce signal reliability is the handicap principle of Amotz Zahavi. Eavesdropping refers to the use of signals by unintended receivers and represents another way that signaling systems can be diverted from the functions for which they originally evolved. In the study of human language, pragmatics concerns how context influences communication in general and meaning in particular.
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Recordings were made of contact-location vocalizations and behaviors of six troop-living juvenile stumptail macaques. Quantitative analysis of 354 spectrograms distinguished thirteen of the fifteen pairs of animals and led to construction of a "profile" of distinctive acoustic features for the vocalizations of each animal. Individual variation was also found in vocalization occurrence rates in five contextual categories. Acoustic distinctions found between two behavioral contexts were the same found to differentiate similar social settings in Japanese macaques (GREEN, 1975). Individual differences in acoustic features and rates of vocalization are correlated with stages of social development, serve as contextual cues, and are an important source of variability in primate communication.
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In the analysis of animal communication, the roles of three necessary primary components of the event of any communication (a communicator, a signal, and a recipient) must be understood. This requires use of the concepts message, meaning, and both immediate and historical context. These concepts and their relationships are explained and exemplified.
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Snake naive and experienced California ground squirrels (Spermophilus beecheyi) were video taped while interacting with either a gopher snake or rattlesnake in a simulated burrow dimly illuminated with red light. Using nonvisually guided behavior, naive and experienced squirrels reacted to snakes in qualitatively similar ways, and behaved more defensively toward snakes than toward a control stimulus (white rat). The squirrels alternately interacted with the snake and attempted to escape from the burrow, which had a sealed entrance. Interaction with the snake included cautious approach in elongate postures, prolonged investigation of adjacent alleys before entering them, kicking sand at the snake, frequent tooth chattering, occasional calling, and building burrow plugs out of sand. These they packed by butting with their heads. When permitted to escape from the burrow, they turned just outside the entrance to tail flag, kick sand, scent mark, and finally plug the burrow. Since visual cues were not available, olfactory and auditory stimuli from the snake appeared to mediate snake-directed behavior in the burrow.
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It is a sobering yet ultimately healthy experience to reread the works of great men of science and to discover the extent to which they anticipated ideas and developments that we of our generation had fondly thought to be original. Many biologists have made such discoveries in the writings of Charles Darwin. As a student of animal behavior I have had this experience with the works of some of the great German zoologists such as Heinroth and Lorenz and most recently, in the writings of Robert Yerkes. A quotation from 1925 bears so directly on the occasion of the Yerkes Centennial that I would like to quote it in full. He is speaking about the vocalizations of higher primates with special reference to the chimpanzee: Everything seems to indicate that their vocalizations do not constitute true language, in the sense in which Boutan uses the term. Apparently the sounds are primarily innate emotional expressions. This is surprising in view of the evidence that they have ideas, and may on occasion act with insight. We may not safely assume that they have nothing but feelings to express, or even that their word-like sounds always lack ideational meaning. Perhaps the chief reason for the apes’ failure to develop speech is the absence of a tendency to imitate sounds. Seeing strongly stimulates to imitation; but hearing seems to have no such effect. I’m inclined to conclude from various evidences that the great apes have plenty to talk about, but no gift for the use of sounds to represent individual, as contrasted with racial, feelings or ideas. Perhaps they can be taught to use their fingers, somewhat as does the deaf and dumb person, and thus helped to acquire a simple, nonvocal, “sign language.” (Yerkes 1925:179–180)
Chapter
Communication consists of the transmission of information from one animal to another. Information is encoded by one individual into a signal. When received by another animal, this information undergoes decoding, while still retaining a specifiable relationship to the encoded information. The relationship is sometimes deterministic, sometimes only probabilistic. During such encoding and decoding, the carrier of the information and the format of the information undergo many transformations. Starting with the original designatum or referent, information passes through a series of steps internal to the signaling animal before effecting a change of state of the signaling organ. A signal is then propagated in a medium. Further steps follow, from transmitted signal to receptor organs of a recipient, from sensory to central processing, and eventually to a recipient’s overt or covert response.
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Aspects of the ecology of vervet monkeys (Ceropithecus aethiops) are described on the basis of a 21 month field study in East Africa. Analysis of home range utilization demonstrated differences between 4 groups. The smallest group distributed its time over a greater area than did the other groups. For 3 of the groups there appeared to be a strong relationship between group size and the amount of optimal habitat defended. The smallest group defended more optimal habitat than expected. However, this same group spent only 60% of its time in this habitat, whereas the other groups all spent more than 95% of their time in it. The smallest group may have avoided the optimal habitat of its territory as an area of frequent intergroup aggression, and as a result utilized a larger and less productive area. Sleeping-tree preferences of groups and individuals are described and discussed. The minimal distance traveled each day by vervet groups varied from 148 to 2,797 yd. In comparing the mean daily distance covered by 2 groups of equal size it was found that one moved significantly further than the other. More trips were made to permanent water holes between 1300 and 1500 hr and during the dry season than at other times. The frequency of group progressions was greatest at 0700 to 1000 and 1600 to 1900 hr. Study of food habits shows that they were opportunistic omnivores. Elephants were the greatest food competitors of the vervets. The monkeys had at least 16 potential predators. Outside of parks and reserves the greatest predator was the European commercial trapper. Ecological characteristics of vervets and their niche separation from baboons are discussed.
Article
Between 1964 and 1971 the population of vervet monkeys in the Amboseli Reserve, Kenya, has declined 33.3%. There were significantly fewer young juveniles (0.5-1.5 years) in 1971 than in 1963-1964. The same birth season was adhered to in 1971 as in 1963-1964.
Article
In one field and two laboratory experiments, wild, wild-captured and partly laboratory-raised 16 to 18-day old great tit nestlings were subjected to repeated presentations of auditory stimuli of varying biological significance. The frequency of occurrence of the stimuli in the study area was censused. — All nestlings showed strong aversive reactions to the ‘seeet’ alarm-call of the species. It is concluded that a selective responsiveness to this call develops independently of previous exposure to it. A functional interpretation of this reaction is derived from its presumed adaptive value. Three hypothetical interpretations are suggested to explain its emergence in the individual nestling; The ‘seeet’-call elicits aversive reactions because of, 1) its novelty, 2) its intensity in terms of relative concentration of energy over its frequency range and 3) its contrasting acoustic structure compared to the nestlings' begging-call which has become strongly associated with approach behavior.
Article
Opinion has shifted during the last decade about the ability of chimpanzees to learn language. Recent projects have reversed earlier failures to establish communication between man and chimpanzee by bypassing the troublesome (for chimpanzees) vocal medium of language. Nevertheless, just what a chimpanzee can learn about language remains controversial. Through the media of American Sign Language (e.g., Gardner amp; Gardner 1969) and the artificial visual languages invented by Premack (1970a) and by Rumbaugh and Glasersfeld (1973), chimpanzees have been taught to produce and comprehend far greater vocabularies than were thought possible following the unsuccessful attempts of the Hayeses (1951), the Kelloggs [1933 (1967); this volume], and others to communicate with chimpanzees via vocal languages. What is at issue is whether a chimpanzee can master relationships between words—in particular, relationships as expressed in sentences.
Article
Cercopithecus aethiops in Amboseli National Park, Kenya, are preyed upon by mammalian carnivores, eagles, baboons, and snakes. High-ranking adult males and females gave alarm calls more often than low-ranking adult males and females. There was some tendency for females who alarm-called most often to precede other females in group progressions. Adult males who gave most alarm calls were more likely than other males to have fathered the group's juveniles and infants. Among adult females there was no correlation between number of offspring and frequency of first alarm calls. The offspring of high-ranking females may have been more vulnerable than other immatures to predation, possibly in part a consequence of the tendency of the offspring of high-ranking females to precede other juveniles in group progressions. Vervets of all age/sex classes alarm-called most at predators to which they themselves seemed to be most vulnerable. Adult vervets gave relatively few alarm calls to predators to which only their offspring were vulnerable, even though such alarm calls would have been of low cost to themselves and of great potential benefit to their offspring. Some aspects of the alarm-calling behaviour of vervet monkeys are consistent with the hypothesis that it has evolved to benefit kin: in other respects their alarms appear to have the consequence of benefiting only the alarmists themselves.-from Authors
Article
1. A group of 32 yellow baboons (Papio cynocephalus) in the Masai-Amboseli National Park, Kenya, caught and ate 45 vertebrate prey items during 2519.19 hours of observation. 2. Eighty percent of the prey items were mammals and the most frequently eaten species were African hares (Lepus capensis), vervet monkeys (Cercopithecus aethiops) and neonate gazelle (Cazella granti and G. thomsoni) in that order. The details of predatory behavior for each prey species are described. 3. Rates of predation were significantly higher during the long dry season than during other months of the year, although no correlation was found between total monthly rainfall and monthly rates of predation. A lognormal model however provided a good fit to the monthly rate of predation data suggesting that the rate of predation by Amboseli baboons was affected by several factors that acted multiplicatively with respect to each other and were themselves related to rainfall or dryness. 4. A mean of 2.3 individuals fed directly from the carcass of each prey item. A mean of 3.5 individuals per prey item fed directly or indirectly, i.e., on scraps, from each carcass. In general, both the number of individuals who fed from each carcass and the duration of their feeding bouts was dependent upon the gross body size of the prey item. Adult males fed directly from the carcass of prey items for about three times more minutes than expected from their number in the group; other classes of individuals fed directly from prey carcasses for only one-fourth as many minutes as expected. In general, an adult male would be expected to feed on each category of vertebrate prey at least once per year, while individuals of all other age-sex classes would be expected to feed on most prey categories only once every two years. 5. The most frequent social behavior around prey items was agonistic bouts; no cooperation, simultaneous feeding or specific begging gestures were observed. 6. Estimates of the total number of prey killed annually by Amboseli baboons indicate that baboon predation probably has a negligible effect on prey populations other than vervet monkeys. 7. It is speculated that the need for vitamin B12 underlies baboon predatory behavior, and perhaps that of other primate species as well.
Article
On the basis of 2255 hr contact with free-living gorilla, and considerable observation of two captive infants, sixteen types of vocalization are described. Some of these could be grouped to give twelve basic categories. For each of the sixteen types data are presented on the frequency with which it is given by each age/sex class, the contexts in which it is given, the nature of the responses elicited from the various age/sex classes, etc.
Article
Seven major types of sampling for observational studies of social behavior have been found in the literature. These methods differ considerably in their suitability for providing unbiased data of various kinds. Below is a summary of the major recommended uses of each technique: In this paper, I have tried to point out the major strengths and weaknesses of each sampling method. Some methods are intrinsically biased with respect to many variables, others to fewer. In choosing a sampling method the main question is whether the procedure results in a biased sample of the variables under study. A method can produce a biased sample directly, as a result of intrinsic bias with respect to a study variable, or secondarily due to some degree of dependence (correlation) between the study variable and a directly-biased variable. In order to choose a sampling technique, the observer needs to consider carefully the characteristics of behavior and social interactions that are relevant to the study population and the research questions at hand. In most studies one will not have adequate empirical knowledge of the dependencies between relevant variables. Under the circumstances, the observer should avoid intrinsic biases to whatever extent possible, in particular those that direcly affect the variables under study. Finally, it will often be possible to use more than one sampling method in a study. Such samples can be taken successively or, under favorable conditions, even concurrently. For example, we have found it possible to take Instantaneous Samples of the identities and distances of nearest neighbors of a focal individual at five or ten minute intervals during Focal-Animal (behavior) Samples on that individual. Often during Focal-Animal Sampling one can also record All Occurrences of Some Behaviors, for the whole social group, for categories of conspicuous behavior, such as predation, intergroup contact, drinking, and so on. The extent to which concurrent multiple sampling is feasible will depend very much on the behavior categories and rate of occurrence, the observational conditions, etc. Where feasible, such multiple sampling can greatly aid in the efficient use of research time.
Article
Ecological changes in an East African Game Reserve may be attributed to changes in climatic conditions and soil salinity. Tree damage from elephants and overgrazing by livestock are probably secondary factors.
Article
East Africa is a country very rich in birds of prey, both resident and migrant, partly because a majority of migrant Eurasian birds of prey enter Africa through Suez in winter. Diurnal birds of prey are both more numerous and more varied than nocturnal, especially among migrant species. The size range of birds of prey, both diurnal and nocturnal, in East Africa is nearly equivalent to that occurring in the whole world. The predator-prey relationship is thus exceedingly complex in East Africa. Diurnal birds of prey hunt by sight and nocturnal by the use of sight and hearing. Diurnal birds of prey can thus make use of both live and dead prey, but owls are only able to capture living prey and do not feed upon carrion. Almost all animals in East Africa, from elephants to small insects, are either eaten as carrion or preyed upon as live prey by some species of raptor. Most live animals in the size range from small insects to animals 5 kg in weight are preyed upon by a diurnal or a nocturnal bird of prey at some stage of the twenty-four hours. Carrion is not consumed by birds of prey at night. Comparison of the raptor avi-fauna of forests with that in savannah indicates that in forests raptors are much less likely to eat carrion than in open country, but that the size range of raptors preying upon live animals is much the same in forests and in open country. Nocturnal birds of prey are less successful in a forest environment than are diurnal species. The possible effect of individual species (Aquila wahlbergi and Polemaetus bellicosus) and of a combination of many species on the possible population of animals in home ranges of known size is discussed. It is concluded that there is no evidence that either an individual species or a combination of several could effectively limit the populations of certain prey species. Concentrations of several breeding pairs of large raptors in apparent association with one another are mentioned. The interrelations of such species, and the effects of possible competition between members of such associations, are discussed. It is concluded that real competition is likely to be slight and that such groups of nesting raptors must be due to a form of inter-specific gregariousness.
Article
Titmice vocalizations are presented with a view to examining variation within and between species. Analyses are derived from field recordings of British Parus species, and from available disc recordings. Spectrographic and oscillographic analyses are made of territorial song and alarm calls. The extent of song divergence and alarm call convergence is illustrated and discussed in addition to data on variation of these calls within species. Some brief notes on field behaviour are included and methods of sound production in birds discussed.
Article
In the field, we videotaped the reactions of squirrels to playbacks of 1, 3 and 5 whistle vocalizations at two sound intensities differing by 10 dB. The squirrels reacted by running to boulders or burrows and freezing. As time progressed following playbacks, freezing declined and squirrels resumed feeding, locomotion and grooming. With increasing numbers of whistles, squirrels were more likely to run and less likely to mount a boulder. With more high intensity whistles, squirrels froze quadrupedally more and bipedally less. Freezing postures did not vary as a function of the number of low-intensity whistles. Walking was suppressed least by 1 and 3 whistles at low intensity, and inhibited most by all high-intensity whistles as well as by the low-intensity 5-whistle playback. When the squirrel was on a boulder, quadrupedal freezing was more common than bipedal freezing. Off the boulder, the two freezing postures were equally likely. We propose that squirrels assessed risk from information encoded in the whistle(s) and contextual to it, and varied their reactions as a function of apparent risk.
Article
. 1The voice of the Chaffinch has been studied by making recordings and analysing them on a sonograph. The contexts in which each call is given are described.2The 14 basic calls are flight, social, aggressive and injury calls, three alarm calls, subsong and song, three courtship calls and the begging calls of nestlings and fledglings. With their variations they give 21 different signals.3The ontogeny of certain calls and the occurrence of intermediate forms suggest how voice may have evolved in the Chaffinch. A hypothetical ancestral type agrees with certain Cardueline finches, implying a closer relationship than recent anatomical studies suggest.4Unlike many displays, calls often occur without an obvious conflict in motivation.5The voice of Chaffinches reared in isolation is usually normal, but song is usually abnormal and in nature is perfected by learning from other birds. The social call is sometimes abnormal and may sometimes be modified by learning under natural conditions.6The communicatory function of voice has been assessed by studying the responses of other Chaffinches to it. By comparison with other contexts in which the same response occurs, a list of “information received” is constructed. The recipient responds as though this has been received.7Four general types of information are involved, social and environmental, identifying and locating.8Inter-specific communication occurs with other woodland Passerines, especially through alarm calls. The alarm calls are of a type difficult for predators to locate. Different families have independently evolved the same type of call for this purpose. Other alarm calls of many species, used to draw attention to the position of a predator, are adapted to be easy to locate.9The general structure of many calls can be understood in terms of the need to facilitate or hinder location of the calling bird.10There are other factors governing the form of voice, especially the need to differ from the calls of other sympatric species. This only applies to calls communicating certain types of information. Some of those exempt from this need for divergence may be especially useful in phylogenetic study.11The two main types of response to voice are related to the different types of information conveyed by the calls. Mechanisms of response are discussed, and the differences between the languages of the Chaffinch and of man.
Article
California ground squirrel alarm vocalizations were recorded in field and laboratory, and sonagraphically analysed. The contexts of both naturally occurring and experimentally elicited calls were noted in the field. The components of this graded system are chatters, chats and whistles. Chatters and chats are often elicited by terrestrial predators, whistles commonly by low flying raptors. Whistles are more commonly associated with cryptic behavior and flight than chatter-chats, but both call types usually elicit bipedal alert postures. These calls grade along a number of dimensions which may signal redundantly the level of excitation of the caller. We propose that the chatter-chat calls of highly aroused squirrels are composed of more and longer notes, occur at a higher rate, are less noisy and contain more frequency modulation. Whistles, however, are single-note calls that contain no frequency modulation, even though they are emitted by highly aroused squirrels and are long and noise free. Preliminary data suggest that: 1) chats are easier for a human ♀ to localize than whistles; 2) elevation of the head, by adopting bipedal postures and mounting promontories, enhances the audibility of alarms.
Article
When exposed to an anesthetized snake, feral black-tailed prairie dogs living in a high-snake-density area approached ambivalently and investigated the snake, typically near the head. Snake-investigation was interrupted intermittently, when the prairie dog jumped away, foot thumped or jump yipped, and approached the snake again. This behavior attracted other prairie dogs, who behaved similarly. Message analyses of two apparent signaling acts — foot thumping and jump yipping — demonstrated that they convey information that withdrawal from the snake has become less likely, and continued interaction with the snake more likely. Prairie dogs in a zoo and feral prairie dogs in a low-snake-density area were unresponsive to immobile snakes, but reacted strongly when the snake was permitted to move. We compared these results to similar data on California ground squirrels and discussed the selection pressures, and ontogenetic and perceptual processes that may have acted as determinants of this snake-directed behavior.
Article
1. The purposes of this study were to assess the response eliciting properties of five structural variants of the California ground squirrel alarm call system, and to compare the responsiveness of females with and without young to the vocalizations. Tape recordings of alarm calls and control sounds were played back in the field to adult female ground squirrels. The squirrels responded very little to control sounds. Following alarm calls, however, posture height and running increased; feeding, walking and non-locomotion movements decreased. None of the playbacks elicited vocalizations from the squirrels. 2. The four chatter-chat calls evoked patterns of response that were distinctly different from reactions to the whistle. The immediate running response to chatter-chats was followed quickly by upright posturing, which subsequently declined throughout the 3-min period following the call. Feeding was suppressed throughout the 3-min post-chatter-chat interval, but movement increased after initial inhibition. After the initial running response to whistles, walking was common and upright posturing was delayed until the second post-call minute. Feeding and nonlocomotion movement were initially suppressed but increased monotonically over time. We proposed that these differences were adaptively related to the fact that chatter-chats typically follow detection of terrestrial predators, whereas whistles usually signal flying raptors. 3. The responses to the four chatter-chat calls were graded in intensity, reaching higher levels in response to calls with more notes and lower noise content. The chat, a one-note call with high noise content, evoked the weakest reaction. We proposed that these two dimensions of calling (number of notes and noise content), in conjunction with several other semi-independent parameters, provide a sufficient diversity of signals to permit specification of the referent of the call (conspecific or predator) as well as the arousal level of the caller. 4. We hypothesized that kin selection was responsible for the greater responsiveness of parous than of nonparous females to the alarm calls, and we discussed some implications of this difference.
Article
Arctic ground squirrels, Citellus undulatus, produce six distinctly different sounds. Each of these sounds may represent a signal in itself, but combinations of these acoustic elements or repetition of a single element produce additional signals. Several of these signals serve as alarm calls. One sound element consists of a short (0.05 sec) broad frequency chat while another is a longer (0.16 to 0.25 sec) descending narrow frequency whistle. Squirrels utter three-note chatter calls when approached by a ground predator, and a series of five or more chatters, which fade in intensity, is given upon the close approach of a ground predator as the squirrel escapes into a burrow. A single whistle, which resembles the alarm call of some birds, is given upon the approach of an aerial predator. This call is repeated at approximately six to eight second intervals if the predator alights near a squirrel and remains nearby.
Article
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