Optimal foraging theory predicts effects of environmental enrichment in a group of adult golden lion tamarins

Abstract 10.1002/(SICI)1098-2361(1998)17:33.3.CO;2-F The success of environmental enrichment programs in effecting specific changes in the behavior of captive animals has not always been uniform. Separate studies demonstrated both an increase in food competition and a decrease in food competition among captive group-living primates upon introduction of foraging devices. The objectives of this study were to measure […]

Chimpanzees, Pan troglodytes, share food in the same way after collaborative and individual food acquisition

We investigated the hypothesis that patterns of chimpanzee food sharing are influenced by whether individuals contributed to its acquisition collaboratively. In two experiments we exposed pairs of captive chimpanzees to food acquisition/sharing situations in which we manipulated (1) whether or not the two individuals had worked together collaboratively to retrieve the food and (2) the […]

Dominant nestlings displaying female-like melanin coloration behave altruistically in the barn owl

When competing over parental resources, young animals may be typically selfish to the point of siblicide. This suggests that limited parental resources promote the evolution of sibling competition rather than altruistic or cooperative behaviours. In striking contrast, we show here that in 71% of experimental three-chick broods, nestling barn owls, Tyto alba, gave food to […]

Bonobos, Pan paniscus, chimpanzees, Pan troglodytes, and marmosets, Callithrix jacchus, prefer to feed alone

Many primates share food, but the motives behind this food sharing are mostly not known. We investigated individuals’ preference to feed either alone or together with a tolerant partner. Subjects (chimpanzees who are highly competitive around food, bonobos who are more tolerant around food and common marmosets who are cooperative breeders and share food actively […]

Chimpanzees share food for many reasons: the role of kinship, reciprocity, social bonds and harassment on food transfers

There is currently great interest in the phylogenetic origins of altruistic behaviour within the primate order. Considerable attention has been focused on chimpanzees, Pan troglodytes, because they are our closest living relatives and participate in a wide range of collective activities, including hunting and food sharing. Food sharing is of particular importance because it plays […]

Contrasting context dependence of familiarity and kinship in animal social networks

The social structure of a population is a crucial element of an individual’s environment, fundamentally influencing the transfer of genes, information and diseases. A central question in social network analysis is how different traits affect associations within populations. However, previous studies of animal social networks have typically focused on a single predictor or stage in […]

Intranasal oxytocin increases social grooming and food sharing in the common vampire bat Desmodus rotundus

Intranasal oxytocin (OT) delivery has been used to non-invasively manipulate mammalian cooperative behavior. Such manipulations can potentially provide insight into both shared and species-specific mechanisms underlying cooperation. Vampire bats are remarkable for their high rates of allogrooming and the presence of regurgitated food sharing among adults. We administered intranasal OT to highly familiar captive vampire […]

Voluntary food sharing in pinyon jays: the role of reciprocity and dominance

Food sharing offers a clear example of prosocial behaviour, in which one individual’s actions benefit another. Researchers have proposed a range of hypotheses that explain why food sharing may occur among unrelated individuals. Two such hypotheses, reciprocity and dominance, have been tested in many species, including fish, corvids, rats, bats and primates, showing that (1) […]