Nesting, sleeping, and nighttime behaviors in wild and captive great apes

The past few decades have seen a burgeoning of scientific studies on great apes’ use of nests for sleeping in the wild, as well as their nesting behavior and sleep in captivity. We review recent advances in knowledge of these topics, with the aim of promoting information exchange between people working in the field and […]

Personality in the behaviour of great apes: temporal stability, cross-situational consistency and coherence in response

Using a multidisciplinary approach, the present study complements ethological behaviour measurements with basic theoretical concepts, methods and approaches of the personality psychological trait paradigm. Its adoptability and usefulness for animal studies are tested exemplarily on a sample of 20 zoo-housed great apes (five of each of the following species): bonobos, Pan paniscus; chimpanzees, Pan troglodytes […]

Effect of spatial crowding on aggressive behavior in a bonobo colony

Abstract 10.1002/zoo.20024.abs According to a previously proposed coping model (De Waal [1989] Zoo Biol. 1(suppl):141–148), gregarious primates will react to crowding by adjusting their behavior in order to limit the amount of aggression displayed. Depending on the duration of the crowding, this can be achieved by the use of different strategies. Chimpanzees (Pan troglodytes) react […]

Food-associated calling sequences in bonobos

When encountering food, chimpanzees, Pan troglodytes, and some other primates produce specific calls, whose acoustic structure covaries with the caller’s food preference. For chimpanzees, there is evidence that listeners use these contingencies to guide their own foraging behaviour. Here, we investigated the vocal behaviour of another great ape, the bonobo, Pan paniscus, in response to […]

Sharing the motivation to play: the use of signals in adult bonobos

Gestures and facial displays are involved in regulating many aspects of mammal social life such as aggression, dominance-subordinate relationships, appeasement and play. Playful activity is an interesting behaviour for examining the role of signals as intentional communication systems. When animals play they perform patterns that are used in other serious contexts. To avoid miscommunication, many […]

Play behavioural tactics under space reduction: social challenges in bonobos, Pan paniscus

Several studies have suggested that primates vary in their response to spatial reduction, which represents a challenge for captive animals. Under spatial reduction, primates can adopt various strategies to reduce social tension. Such strategies, which are not mutually exclusive, can involve avoidance and coping tactics. Recently, it has been shown that, during short-term crowding, bonobos […]

What do bonobos (Pan paniscus) understand about physical contact?

The present study aimed to test what bonobos ( Pan paniscus ) understand about contact. The task consisted of a clear horizontal tube containing a piece of food and a stick with a disk attached. The bonobos chose which side to push or pull the stick for the disk to contact the food and make […]

Bonobos and chimpanzees infer the target of another’s attention

We examined the ability of bonobos, Pan paniscus (N ¼ 39), and chimpanzees, Pan troglodytes (N ¼ 74), to infer the target of an experimenter’s visual attention in a series of three experiments. In each experiment subjects were first introduced to a novel object while an experimenter’s (E1) visual access to this object was manipulated […]

Mate competition, testosterone and intersexual relationships in bonobos, Pan paniscus

Variation in male testosterone levels across and within species is known to be related to mating systems, male dominance rank and aggression rates. When aggression enhances access to mates, dominance status and androgen levels correlate positively. Deviation from this pattern is expected when access to females is determined by factors other than male dominance or […]

Onset and Early Use of Gestural Communication in Nonhuman Great Apes

The early gesturing of six bonobos, eight chimpanzees, three gorillas, and eight orangutans was systematically documented using focal animal sampling. Apes’ were observed during their first 20 months of life in an effort to investigate: (i) the onset of gesturing; (ii) the order in which signals of different sensory modalities appear; (iii) the extent to […]