Uses of nonhuman primates by humans in northeastern Brazil.

Humans have used non-human primates (hereafter referred to as primates) as food source, medicine, parts of rituals, pets, and models for various studies worldwide. Here we investigated the extent of the use of primates by humans in three areas in northeastern Brazil, the country's most impoverished region. We carried out our study in three biomes (Caatinga, Cerrado, and Atlantic Forest). The results showed that humans exploited all five primate species occurring in the study sites: Callithrix jacchus, Sapajus flavius, Sapajus libidinosus, Alouatta belzebul, and Alouatta ululata. They used the primates as a food source, as pets and medicines, and for leisure. Despite socioeconomic differences in the study areas, we found similarities in the use of primates. Larger primates were targeted for meat, whereas the small common marmosets were targeted as pets. We found conflicting interactions between humans and bearded capuchins due to crop raiding, but no such conflict was found between humans and blonde capuchins, reflecting the differences in crop type, pattern, and tradition in the sites. A. ululata was used as medicine. We suggest that environmental education actions in the study areas should focus on (i) raising awareness among local people of the ecological importance of primates, (ii) providing alternative activities to hunting whenever possible, and (iii) minimising conflicts.

Responses towards a dying adult group member in a wild New World monkey.

Compassionate caretaking behaviour towards dying adult group members has been reported as being unique to humans and chimpanzees. Here we describe in detail the reaction of a wild dominant male common marmoset, a neotropical primate, to the accidental death of the dominant female of its group. The male exhibited behaviours towards the dying female that resembled those of chimpanzees and humans. The long-term relationship between the dominant pair (which lasted at least 3.5 years) and their social status in the group may have contributed to the male's behavioural response. The male prevented young individuals from approaching the dying female, behaviour previously observed in chimpanzees. The data provide an interesting insight into compassionate caretaking behaviours in New World primates as well as the pair-bond systems of common marmosets. These are rare observations, and thus their detailed descriptions are essential if we are to create a comparative and enhanced understanding of human and nonhuman primate thanatology.

Caatinga revisited: ecology and conservation of an important seasonal dry forest.

Besides its extreme climate conditions, the Caatinga (a type of tropical seasonal forest) hosts an impressive faunal and floristic biodiversity. In the last 50 years there has been a considerable increase in the number of studies in the area. Here we aimed to present a review of these studies, focusing on four main fields: vertebrate ecology, plant ecology, human ecology, and ethnobiology. Furthermore, we identify directions for future research. We hope that the present paper will help defining actions and strategies for the conservation of the biological diversity of the Caatinga.

Vocalisations of wild common marmosets are influenced by diurnal and ontogenetic factors.

The vocalisations of wild common marmosets, Callithrix jacchus, were recorded to investigate whether call rate by individuals is affected by time of day, age, sex or dominance rank within a group. We also investigated how vocalisation pitch was affected by age, focussing on a single common call, the trill call. Adults vocalised more than juveniles or infants during the majority of daylight hours. Only the call rate of juveniles varied significantly over the day. No differences were found between either sex or dominance rank with respect to rate of vocalisations. The trill calls emitted by young wild common marmosets were of a higher pitch than those emitted by adults. We conclude that the auditory communication of wild common marmosets is related to the age of the animals, both in terms of call rate and the physical characteristics of their vocalisations.

Infanticide and cannibalism in a free-ranging plurally breeding group of common marmosets (Callithrix Jacchus).

Our study presents a detailed description of infanticide and cannibalism in a free-ranging plurally breeding group of Callithrix jacchus. The 1-month-old infant was the daughter of the dominant female, and was attacked by the group's second breeding female. Two months later, the latter gave birth to twins and appeared to have become the dominant female. These findings confirm and extend previous reports of infanticide by pregnant female marmosets, and indicate that infants of dominant breeding female, as well as those of subordinate females, are vulnerable to infanticide in plurally breeding groups. With respect to the cannibalism, this act seemed to be mainly a response to the prompt availability of food, represented by the killed infant.