Comparative locomotor behavior of chimpanzees and bonobos: The influence of morphology on locomotion

Results from a 10 month study of adult male and female bonobos (Pan paniscus) in the Lomako Forest, Zaire, and those from a 7 month study of adult male and female chimpanzees in the Tai Forest, Ivory Coast (Pan troglodytes verus), were compared in order to determine whether there are species differences in locomotor behavior and substrate use and, if so, whether these differences support predictions made on the basis of interspecific morphological differences. Results indicate that bonobos are more arboreal than chimpanzees and that male bonobos are more suspensory than their chimpanzee counterpart. This would be predicted on the basis of male bonobo's longer and more narrow scapula. This particular finding is contrary to the prediction that the bonobo is a “scaled reduced version of a chimpanzee” with little or no positional behavior difference as had been suggested. This study provides the behavioral data necessary to untangle contradictory interpretations of the morphological differences between chimpanzees and bonobos, and raises a previously discussed (Fleagle: Size and Scaling in Primate Biology, pp. 1–19, 1985) but frequently overlooked point–that isometry in allometric studies does not necessarily equate with behavioral equivalence. Several researchers have demonstrated that bonobos and chimpanzees follow the same scaling trends for many features, and are in some sense functionally equivalent, since they manage to feed and reproduce. However, as reflected in their morphologies, they do so through different types and frequencies of locomotor behaviors. © 1993 Wiley-Liss, Inc.     

Greeting behavior during party encounters in captive chimpanzees

Party encounter situations were experimentally produced in a group of captive chimpanzees (Pan troglodytes verus) at the Primate Research Institute of Kyoto University, Japan. During weekends all subjects (two adult males and five adult females) usually stayed together in the rooms (Baseline condition). Under experimental conditions, we shut passages between rooms to divide the subjects into two groups. We examined the effects of temporal separation of group members on affiliative interactions, aggressive interactions, and simple proximity. The frequency of affiliative interactions between male and female chimpanzees and between female chimpanzees increased when they encountered one another after separation, irrespective of male identity or housing history. Therefore we considered affiliative interactions between males and females during party encounters as being the response between separated individuals. The same tendency was not found in the frequency of affiliative interactions between females or between males. Unlike affiliative interactions, neither aggressive interactions nor simple proximity were influenced by separation.     

Fighting dynamics of male copperheads,Agkistrodon contortrix (Serpentes,Viperidae): Stress-induced inhibition of sexual behavior in losers

Adult male copperheads (Agkistrodon contortrix) fight for priority of access to females during the mating periods in spring and late summer. During fights, one male abruptly quits and retreats, and the other chases in pursuit. One male thus emerges as the winner and the other as the loser. Reversal of this outcome does not occur during the time of observation (30 min) nor in 24 hr postfight trials. In all cases, winners gain priority of access to females. Losers, in contrast, do not pursue females nor gain access to them, even when winners are removed from the arena. In this study, courtship performance of male A. contortrix was studied in the laboratory using subjects with either winning or losing experience from staged fights. All males used first were tested with a single female to determine courtship performance prior to the agonistic trials. From these tests, each male was given a single courtship score of 0 (no courtship) to 3 (most intense courtship). Only males receiving a score of 2–3 were used in the initial agonistic trials. All staged fights were conducted in a large arena and involved two males and one female. Following fights, winners and losers were tested again for courtship performance. In trials conducted at 24 hr and 7 days postfight, only losers were tested. It was found that prefight courtship scores were not significantly different between winners and losers. At 30 min postfight, most losers showed complete suppression of courtship behavior (score 0). Winners, in contrast, showed equivalent or an increase in their courtship scores. At 24 hr postfight, courtship scores of losers remained significantly lower than their prefight scores. At 7 days postfight, courtship scores of losers were not significantly difference from their original prefight scores. Fighting behavior in free-ranging A. contortrix represents a potentially significant cost to losers if it is associated with loss of reproductive opportunities. Recent evidence from hormonal studies indicates that inhibition of courtship and fighting behavior in male A. contortrix is stress-induced. © 1996 Wiley-Liss, Inc.     

Intragroup agonistic behavior in captive groups of the common marmosetCallithrix jacchus jacchus

Agonistic behavior was observed in five captive groups of the monogamous monkey Callithrix jacchus jacchus,which normally produces twin offspring every 5 months. Fighting is first recorded when twins are aged 5–10 months. These “twin fights” determine differences in status between combatants that can be detected 5 months later. From what is known of the social behavior of the species, it is postulated that an individual’s twin is its most serious rival and that early fighting is advantageous because injury is minimal while the animal retains its milk dentition. In contrast to twin fights, aggression between same-sex juveniles and adults does not involve long fights and probably serves to reinforce preexisting differences in status. It often results in forcing a group member to the periphery, and therefore, its main function may be to drive mature, same-sexed individuals out of the group. Apart from the relationship between twins, status within the family group is age related and not normally determined by aggression.     

5-HT和DA对虾蟹打斗行为影响的研究进展

5-羟色胺(5-HT)和多巴胺(DA)是两种神经递质,可与众多不同类型的受体结合发挥多种重要的生理功能.现已证明其广泛分布于多种动物的不同组织中,在动物的打斗行为活动中起着重要的调节作用.目前,在虾蟹中已被报道的5-HT受体主要有5种,分别是5-HT1A、5-HT1B、5HT2A、5HT2B和5-HT7;DA受体主要为DA1A、DA1B、DA2和DA4.5-HT和DA及其受体分布存在明显的种属和组织特异性.5-HT和DA参于了虾蟹打斗行为的调节过程并有不同的调节机理.5-HT可以调节环磷酸腺苷(cAMP)或高血糖激素(CHH)的释放,促进或抑制虾蟹打斗行为;而DA同样能够通过调节cAMP及COMT等物质的释放来调节虾蟹打斗行为.     

The effect of peer separation in young chimpanzees (Pan troglodytes)

Ten chimpanzees (Pan troglogytes), aged 18–24 months, housed without mothers as two dyads and two triads, were subjected to social separation. Two issues were addressed: the effects of peer separation in chimpanzees; and differential responses by subjects living in dyads compared with those living in triads. Chimpanzees that were alone during separation reacted with high levels of “protest” alternating with “despair” throughout the separation period. The continued presence of one cagemate, during separation from a third, was a strong mitigating factor. Even when the primary attachment was formed with the absent cagemate, the remaining chimpanzees clung to each other and the levels of protest and despair, when present, were low. Upon reunion, neither “detachment” nor heightened levels of clinging were conspicuous, but there was increased social interaction. The data on separation of chimpanzees are intermediate between those of humans and monkeys separated from mothers or peers. The increased social interactions during reunion, including looking, are comparable to the visual vigilance reported for humans.     

Female sexual behavior in the absence of male-male competition in captive Japanese macaques (Macaca fuscata)

A captive group of Japanese macaques (Macaca fuscata). consisting of one adult male and three adult females, was observed for 88 hr during the 1988 mating season. We focused on the group's sexual activities because understanding how social dynamics affect reproductive behavior may enhance our ability to establish self-sustaining captive populations. The adult male exhibited distinct preferences in copulation partners, although all females were receptive and cycled during the study period. The dominant female participated in the most copulations and successfully harassed and disrupted copulations between the male and the other females. The alpha female, therefore, actively constrained the formation of mating pairs. Further, the male did not consort with his year-round female grooming partner. This female, the least dominant member of the group, engaged in the most autosexual and homosexual behavior. Birth season data show that only the dominant female bore offspring. This study emphasizes the influence of social dynamics on a group's reproductive potential and suggests an alternative means by which females can influence consort formation.     

The influence of social experience on the behavior of male cockroaches,Nauphoeta cinerea

The influence of social experience on rates of agonistic behavior was investigated in a cockroach, Nauphoeta cinerea. Social experience was manipulated by establishing three types of groups of four identically aged males: (1) ran-domly chosen, socially naive males (control); (2) males of similar status and activity level (from treatment 1); and (3) males returned to their original hierarchy after experiencing treatment 2. In the control groups, we found stable hierarchies, significant differences in the rate of agonistic behaviors exhibited among different status males, and a significant relationship between social status and level of agonism. We also compare activity levels within and among groups after males had novel social experiences. Among similar status individuals, we found less activity than when they wereintheir original groups. When males were returned to their original groups, the level of activity increased compared to the level of activity before treatment. The social status of males was unstable after these treatments. Losing tended to result in relatively more subordinate behavior, and winning in relatively more dominant behavior by a male. Within groups, the rate of agonism also increased over 5 days in groups of males that had no previous interactions with each other, while the rate of agonism remained the same in groups of familiar males. We interpret these results in light of male-male assessment and the maintenance of social status in this species.     

Association between burst-pulse sounds and aggressive behavior in captive Atlantic bottlenosed dolphins (Tursiops truncatus)

A specific display observed during agonistic behavior among captive Atlantic bottlenosed dolphins (Tursiops truncatus) was examined. The primary component of the display was an open-mouthed posture accompanied by violent vertical head motions and the emission of pulse-type vocalizations. Jaw-clap behavior produced during the display was quantified for use as an index of aggressive motivation. By aurally monitoring the animals' vocalizations it was found that the level of aggressive response between the participants of the interactions increased with the production and subsequent duration of burst-pulse sounds. The possibility of burstpulse sounds resulting in auditory or tactile discomfort when directed toward conspecifics is discussed.     

The effect of contraceptive implants on the behavior of female Rodrigues fruit bats,Pteropus rodricensis

This study investigated the effects of a melengestrol acetate contraceptive implant on the behavior of captive Rodrigues fruit bats (Pteropus rodricensis). Eighteen female bats (nine controls and nine implanted animals) were studied over three 4 week periods: prior to implantation, immediately postimplantation, and 6 months postimplantation. The only significant differences found 6 months postimplantation were that time spent hanging alert decreased in both groups and, concurrently, amount of time spent engaged in other activities, most noticeably social interactions, increased. In connection with this, the number of nearest neighbors increased. However, these changes were seen in all bats and were also associated with the increasing size of the resident colony. There were no significant differences between the two groups of bats in the number of nearest neighbors or sexual partners over the course of the study. The physical effects of the contraceptive implants, increased weight gain and retarded hair regrowth above the incision site, were very clearly shown. There was a 22% rate of rejection/loss of the implants. None of the implanted bats produced offspring postimplantation. This study has shown that melengestrol acetate implants are an effective way to limit reproduction in female Rodrigues fruit bats, at least in the short term, and have no effect on the behavior of this highly social species. © 1996 Wiley-Liss. Inc.     

Animal behavior and the captive management of wild mammals: A personal view

Behaviorists can undertake noninvasive studies of zoo animals using only the simplest of research tools, unlike those biologists who are concerned with functions below the level of the whole, living organism. With careful interpretation, the results of behavioral studies can be applied to improve the management, husbandry, and exhibition of wild mammals in captivity. This often involves comparisons with research results obtained from studies of animals in the wild, since the behavior of captive specimens may in some measure be altered. Examples are given involving the breeding biology or social organization of three species: (1) barasingha or swamp deer (Cervus duvauceli), (2) mongoose lemur (Lemur mongoz), and (3) drill (Papio leucophaeus). Suggestions are made to improve the allocation of time and resources for research by zoo personnel, including a greater reliance on cooperative efforts to solve problems of common interest.     

Vigilance,vocalizations, and cryptic behavior at retirement in captive groups of red-bellied tamarins (Saguinus labiatus)

Frequent references are made to presumed antipredator adaptations exhibited by callitrichids, but there are very few systematic investigations of these behaviors. One set of untested presumptions stems from observations that callitrichids become especially vigilant and cryptic prior to retirement each evening. This hypothesis was tested in the current study by quantifying the rates of vocalizations and extragroup behavior at various times of the day. Using two groups of captive red-bellied tamarins, it was demonstrated that these primates do become relatively more quiet and more attentive to the nonsocial environment prior to retirement each evening, culminating in virtual silence once the nest box has been entered. While the adaptive significance of these phenomena has not yet been tested, it is likely that the behaviors reduce vulnerability to predation.     

Courtship song, male agonistic encounters, and female mate choice in the house cricket,Acheta domesticus (Orthoptera: Gryllidae)

Whether female crickets choose among males based on characteristics of the courtship song is uncertain, but in many species, males not producing courtship song do not mate. In the house cricket,Acheta domesticus, we examined whether a female chose or rejected a male based on his size, latency to chirp, latency to produce courtship song, or rate of the high-frequency pulse of courtship song (“court rate”). We confirmed that females mated only with males that produced courtship song, but we found no evidence that the other factors we measured affected a female’s decision to mate. In addition, we investigated whether the outcome of male agonistic encounters affected the subsequent production of courtship song. In one experiment, we observed courtship and mating behavior when a single female was placed with a pair of males following a 10-min interaction period between the two males. Winners of male agonistic encounters had higher mating success. However, winners and losers of agonistic encounters were not different in their likelihood or latency to produce courtship song or in the number of times they were disrupted by the other male in the pair. In a second experiment, we allowed two males to interact for a 10-min period, but following this interaction period, we placed a female with each male separately and observed courtship and mating behavior. The mating success of winners and losers was not different under these circumstances, and we found no differences between winners and losers in any subsequent courtship or mating behavior examined. We conclude that winning agonistic encounters influences a male’s mating success in ways other than his production of courtship song and this effect is lost when winning and losing males are separated and each is given an opportunity to mate.     

Influence of food distribution on behavior in captive bongos,Taurotragus euryceros: An experimental investigation

A feeding experiment was conducted to test if Bongo antelopes, being selective feeders searching for clumped quality food, show similar behavior changes as primates under similar conditions. One group of 3 females and 3 calves of Dvur Kralove Zoo was either fed clumped (all food, i.e., leaves and branches of 4 species of tree plus rye grass in one heap), or the same amount distributed over as many heaps as animals present. No increase in agonistic interactions under clumped conditions was found, but non-agonistic and sociopositive patterns increased significantly. Intake of low quality food increased under clumped conditions. Social distances and enclosure use were not significantly different. These findings are in accordance with predictions from models developed for primate feeding strategies, and suggest that selectively feeding antelopes possess behavioral mechanisms for tension-reduction similar to “contest-type” primates. Zoo Biol 16:237–245, 1997. © 1997 Wiley-Liss, Inc.     

Differences in winter activity,courtship, and social behavior of two captive family groups of Mexican wolves (Canis lupus baileyi)

The purpose of this study was to determine differences in activity patterns and social behavior of two groups of endangered Mexican wolves maintained at two quite different facilities and to determine some of the variables that should be considered when making specific behavioral comparisons among wolves in this binational captive breeding program. Quantitative measurements of an Activity Index and social behaviors were obtained for three individuals in each pack. Within each age/sex category, activity, aggression, and play were more frequent in the pack at a zoo facility, compared to the pack at a field station facility. Frequency of courtship interactions and scent marking were significantly higher in the field station pack. The packs were similar in the frequency of active submission, but differed significantly in the pattern of this behavior. Given the large number of interacting variables and small number of individuals in this study, we recommend caution in generalizing results to other packs or facilities. Zoo Biol 16:435–443, 1997. © 1997 Wiley-Liss, Inc.     

The neural and cognitive correlates of aimed throwing in chimpanzees: a magnetic resonance image and behavioural study on a unique form of social tool use

It has been hypothesized that neurological adaptations associated with evolutionary selection for throwing may have served as a precursor for the emergence of language and speech in early hominins. Although there are reports of individual differences in aimed throwing in wild and captive apes, to date there has not been a single study that has examined the potential neuroanatomical correlates of this very unique tool-use behaviour in non-human primates. In this study, we examined whether differences in the ratio of white (WM) to grey matter (GM) were evident in the homologue to Broca's area as well as the motor-hand area of the precentral gyrus (termed the KNOB) in chimpanzees that reliably throw compared with those that do not. We found that the proportion of WM in Broca's homologue and the KNOB was significantly higher in subjects that reliably throw compared with those that do not. We further found that asymmetries in WM within both brain regions were larger in the hemisphere contralateral to the chimpanzee's preferred throwing hand. We also found that chimpanzees that reliably throw show significantly better communication abilities than chimpanzees that do not. These results suggest that chimpanzees that have learned to throw have developed greater cortical connectivity between primary motor cortex and the Broca's area homologue. It is suggested that during hominin evolution, after the split between the lines leading to chimpanzees and humans, there was intense selection on increased motor skills associated with throwing and that this potentially formed the foundation for left hemisphere specialization associated with language and speech found in modern humans.     

Sex differences in adult chimpanzee positional behavior: The influence of body size on locomotion and posture

Focal animal instantaneous sampling of adult male and female chimpanzee positional behavior was conducted during a 7-month study in the Tai Forest, Ivory Coast, in order to determine whether there are sex differences in the locomotion, posture, substrate use, and height preference of sexually dimorphic adult chimpanzees, and if so, whether these differences support predictions based on body size differences. Results indicate that as predicted, adult male and female chimpanzees differ in their arboreal locomotor behavior, with the larger males using less quadrupedalism and more climbing, scrambling, and aided bipedalism than females during feeding locomotion. There is a sex difference in height preference as well, with female chimpanzees consistently using more arboreal behavior than males, primarily during resting. Although it has been previously demonstrated that separate primate species of differing body size differ in locomotor and postural activities (Fleagle and Mittermeier, 1980; Crompton, 1984), this study clearly demonstrates that body size differences within a species can also be correlated with differences in locomotor behavior. These findings may influence how we interpret sex differences in body size of extinct species. © 1993 Wiley-Liss, Inc.     

An experimental study of leaf swallowing in captive chimpanzees: insights into the origin of a self-medicative behavior and the role of social learning

Chimpanzees in the wild swallow the rough hispid leaves of certain plant species as a means of physically expelling intestinal parasites. A plant with such a leaf texture was introduced in 36 trial sessions to a captive group of 11 healthy adult chimpanzees to investigate the possible origin and acquisition of leaf swallowing behavior. One male (housed separately from the group during testing) and one female, both captive born, spontaneously exhibited the behavior on their first trial without prior opportunity to observe others with this plant. Six other chimpanzees on their first trial displayed a phobic response to these leaves and rejected them entirely, while another two chewed and swallowed the leaves in a normal way. Four individuals eventually exhibited the behavior, after having approached and closely observed the leaf swallowing of the first female to exhibit the behavior in the group. Four of the six individuals that initially avoided the leaves never overcame their phobia toward this plant and were not in proximity to a chimpanzee performing leaf swallowing during test sessions. Individuals born to wild chimpanzee mothers were no more likely to perform the behavior than captive-reared group mates. These results suggest that the acquisition of this behavior is based in part on a propensity to fold and swallow rough, hispid leaves, but that the acquisition and spread of leaf swallowing within a group is likely to be socially influenced. This study provides support for the hypothesis that leaf swallowing originated in the wild from opportunistic feeding behavior and was later passed down in the form of a self-medicative behavioral tradition.Electronic Supplementary Material Supplementary material is available in the online version of this article at