Maternal cannibalism in two populations of wild chimpanzees

Maternal cannibalism has been reported in several animal taxa, prompting speculations that the behavior may be part of an evolved strategy. In chimpanzees, however, maternal cannibalism has been conspicuously absent, despite high levels of infant mortality and reports of non-maternal cannibalism. The typical response of chimpanzee mothers is to abandon their deceased infant, sometimes after prolonged periods of carrying and grooming the corpse. Here, we report two anomalous observations of maternal cannibalism in communities of wild chimpanzees in Uganda and Ivory Coast and discuss the evolutionary implications. Both infants likely died under different circumstances; one apparently as a result of premature birth, the other possibly as a result of infanticide. In both cases, the mothers consumed parts of the corpse and participated in meat sharing with other group members. Neither female presented any apparent signs of ill health before or after the events. We concluded that, in both cases, cannibalizing the infant was unlikely due to health-related issues by the mothers. We discuss these observations against a background of chimpanzee mothers consistently refraining from maternal cannibalism, despite ample opportunities and nutritional advantages. We conclude that maternal cannibalism is extremely rare in this primate, likely due to early and strong mother–offspring bond formation, which may have been profoundly disrupted in the current cases.

Small gods, rituals, and cooperation: The Mentawai water spirit Sikameinan

Cognitive and evolutionary research has overwhelmingly focused on the powerful deities of large-scale societies, yet little work has examined the smaller gods of animist traditions. Here, in a study of the Mentawai water spirit Sikameinan (Siberut Island, Indonesia), we address three questions: (1) Are smaller gods believed to enforce cooperation, especially compared to bigger gods in larger-scale societies? (2) Do beliefs in these deities encourage people to engage in behavior that would otherwise be perceived as costly? and (3) Does ritual reinforce beliefs in these deities? Drawing on interview responses, data from healing ceremonies, and ethnographic observation, we show that Sikameinan is believed to punish people who violate meat-sharing norms and that people ‘attacked’ by Sikameinan pay shamans to conduct healing rituals. The public nature of rituals, involving prestigious individuals apologizing to Sikameinan for the patient’s stinginess, reinforce onlookers’ beliefs about Sikameinan. The most widely shared beliefs about Sikameinan are represented in rituals while beliefs not represented vary considerably, indicating that ritual may be potent for cultural transmission. These results suggest that moralizing supernatural punishers may be more common than suspected and that the trend in the cultural evolution of religion has been an expansion of deities’ scope, powers, and monitoring abilities.

Traditional Home Slaughtering of Animals in the Framework of EU Legislation. Evidence from Bosnia and Herzegovina

Traditional home slaughtering of animals is a widespread social practice in the Western Balkans, bringing together families, neighbours, and friends, and contributing to the rise of social capital. Bosnia and Herzegovina is a multicultural country where traditional home slaughtering of animals is mostly practised as seasonal slaughtering by Christian communities and as religious slaughtering by Muslim communities. In the framework of existing EU legislation, meat that comes from home slaughtering can be used for private consumption only. However, these rules are not fully aligned with the practices existing on the ground. This article argues that the Western Balkans’ integration into the EU can affect the sustainability of these practices, and it is therefore necessary to amend the relevant legislation and policies to ensure the implementation of EU regulations while respecting the traditional way of communal meat sharing.

Courtesy food sharing characterized by begging for social bonds in wild bonobos

Food sharing has played an important role in the evolution of cooperation, especially in hominization. Evolutionary theories regarding food sharing have been based mainly on chimpanzee meat sharing. However, in bonobos, our other closest evolutionary relatives, food sharing occurs in considerably different ways than it does in chimpanzees. Bonobos often share plant food, which can often be obtained without any cooperation or specialized skills, sometimes even when the same food items are abundant and easily available at the sites. The characteristics of bonobo food sharing appear to be at odds with previous hypotheses, such as reciprocity and sharing under pressure, and urge us to shift our viewpoint from the food owner to the recipient. This chapter proposes that recipients beg to strengthen social bonding as well as to gain access to the food itself. Frequent fruit sharing among bonobos may shed light on the evolution of courtesy food sharing to enhance social bonds in a resource-rich environment. Le partage de la nourriture a joué un rôle très important dans l’évolution de coopération, spécialement dans la hominisation. Les théories évolutionnaires sur le partage de la nourriture sont basées, pour la plupart, sur le partage de la viande par les chimpanzés. Cependant, chez les bonobos, nos autres parents évolutionnaires, le partage de la nourriture est fait d’une manière très différente que chez les chimpanzés. Les bonobos partagent fréquemment les aliments végétaux, qui sont obtenus sans coopération et sans compétences spécialisées, et parfois le font même quand cette même nourriture est facilement accessible aux sites. Les caractéristiques du partage de nourriture chez les bonobos contredisent des hypothèses précédentes, comme celle de la réciprocité et du partage-sous-pression, et nous poussent à changer la perspective du propriétaire de la nourriture à celle du bénéficiaire. Nous proposons que les bénéficiaires supplient pour commencer à se lier socialement, et pour accéder à la nourriture. Le partage fréquent des fruits chez les bonobos peut nous informer sur l’évolution du partage de nourriture par politesse pour augmenter les liens sociaux dans un environnement plein de ressources.

Meat sharing between male and female Guinea baboons (Papio papio)

Meat sharing in non-human primates has been linked to a variety of functions, including harassment reduction, mate provisioning and status enhancement. We present observational data regarding male prey capture and male–female meat sharing in wild Guinea baboons. Guinea baboons live in a multilevel society that comprises units of males with associated females and, sometimes, secondary males. Several males of different units maintain strong bonds, resulting in the formation of parties within gangs. Female–male relationships persist irrespective of female reproductive states, yet females may also switch between males at all stages of the reproductive cycle. Our data show that males capture and kill a variety of prey, including hares and antelope. Males shared meat passively only with females in their social and reproductive units. The occurrence of oestrus females in the gang did not influence whether or not sharing would occur in that males did not share with oestrus females unless an affiliative relationship already persisted, indicating that short-term currency exchanges of meat for sex are unlikely. We hypothesise that males may benefit from feeding tolerance by retaining females, while females may increase access to potentially nutritious and rare food sources. Alternatively, females may prefer males that are generally less aggressive and thus also more likely to share meat. Long-term data will be needed to ultimately distinguish between the two accounts. Although there is no evidence that males intentionally provide necessary resources to particular females during times of high energetic demands and decreased foraging efficiency, as has been found in humans, and meat sharing is generally rare, it may have subtle, yet important effects on the maintenance of bonds in Guinea baboons.

Non-reciprocal but peaceful fruit sharing in wild bonobos in Wamba

Food sharing is considered to be a driving force in the evolution of cooperation in human societies. Previously postulated hypotheses for the mechanism and evolution of food sharing, e.g., reciprocity and sharing-under-pressure, were primarily proposed on the basis of meat sharing in chimpanzees. However, food sharing in bonobos has some remarkably different characteristics. Here I report details pertaining to fruit sharing in wild bonobos in Wamba based on 150 events of junglesop fruit sharing between independent individuals. The bonobos, primarily adult females, shared fruit that could be obtained individually without any cooperation or specialized skills. There was no evidence for reciprocal exchange, and their peaceful sharing seems to contradict the sharing-under-pressure explanation. Subordinate females begged for abundant fruit from dominants; this might indicate that they tested the dominants’ tolerance based on social bonds rather than simply begging for the food itself, suggesting existence of courtesy food sharing in bonobos.