Interactions with humans reduce the success of foraging for anthropogenic food by capuchin monkeys (Sapajus libidinosus) in Brasília National Park, Brazil.

The progressive growth of urban environments has increasingly forced populations of nonhuman primates to coexist with humans in many cities, which has resulted in problems such as behavioral alterations, conflicts with humans, and threats to the health of the monkeys, due to their consumption of anthropogenic foodstuffs. These anthropogenic foods, which are rich in calories, are the principal driver of the proximity between humans and primates, even though the acquisition of these foods tends to be risky for the monkeys and involve a variety of challenges derived from specific features of the urban environment. The present study evaluated the success/risk relationship of foraging for anthropogenic food by tufted capuchins (Sapajus libidinosus) in Brasília National Park. The data were analyzed using a binary logistic regression, with the backward-stepwise Wald method, to investigate the factors related to the foraging success of the capuchins, considering variables such as their sex and age, the type of approach and its context, and interactions with humans. The capuchins were influenced by the anthropogenic context, which affected their foraging strategies and diet. Interactions with humans reduced the success of foraging for anthropogenic foods. Conflicts between humans and the capuchins were common, especially in the context of access to food. The capuchins thus preferred to access feeding resources directly, probably due to the reduced human interference, which resulted in greater foraging success for unattended food brought by park visitors and the raiding of trash cans. Based on the observed behavior patterns, a number of measures can be proposed to mitigate these conflicts. These recommendations include not bringing food into areas frequented by the capuchins, not reacting to approaching animals, and removing all trash generated during a visit. A cleaning team dedicated to the maintenance of the visitation area free of anthropogenic waste is also be recommended.

Disputes over provisioned resources are no more intense between groups than within groups in free-ranging Sapajus libidinosus.

Socioecological models predict that disputes between primate groups will be more intense than those within groups, given that the systematic loss of contests over a given resource will restrict the access of all of the members of that group to that resource. Higher levels of aggression are also expected for provisioned resources that have a more lucrative cost:benefit ratio. The levels of aggression in and between two free-ranging tufted capuchin monkey (Sapajus libidinosus) groups in the context of daily provisioning with bananas were evaluated. The aim of a complementary analysis was to identify possible predictors of the frequency of disputes at the site of the provisioned resource. The disputes were recorded using all-events sampling, while the social behaviour of the study groups was recorded by instantaneous scan sampling. The data were analysed using t-test, Mann-Whitney's U, and generalised linear modelling. Between-group disputes were no more intense than within-group events, and did not involve more individuals, or more adult females. The frequency of disputes increased as the number of individuals eating bananas increased. No evidence was found that disputes between groups were any more intense than those within groups. Dominance patterns may have affected these findings, by mediating intergroup disputes. An increase in the number of competitors affected the frequency of disputes at the site of the provisioned resource.

Time budget and foraging strategies of two provisioned groups of tufted capuchin monkeys, Sapajus libidinosus, in a small, seasonal urban forest fragment.

Studies of urban monkeys provide important insights into the behavioral flexibility of primate species. We studied two provisioned groups of capuchin monkeys that inhabit a small forest fragment in the city of Goiânia, Brazil. One of the groups was dominant and had priority of access to both native and provisioned resources. Anthropic resources were available in two relatively small areas within this forest, but varied in their quality. We hypothesized that intergroup dominance and the seasonality of native resources would have different impacts on the foraging strategies and use of space by the two study groups. Data on the location of the members of the two groups, their behavior, and consumption of different food items were collected during five dry season and five rainy season months. The members of the dominant group spent more time in the provisioned area where anthropic food was less costly to obtain and consumed more provisioned fruit and vegetables than the members of the subordinate group. The differences between groups were exacerbated during the dry season, when sources of native fruit were less abundant. The results of the present study illustrate how capuchins may respond to the variation in proximate factors, such as intergroup dominance and seasonality. These factors were determinants to the variation in the diet and the use of space observed between the two study groups.

Sex differences in vocal patterns in the northern muriqui (Brachyteles hypoxanthus).

We investigated whether sex differences in spatial dynamics correlate with rates of staccato and neigh vocalizations in northern muriquis (Brachyteles hypoxanthus) at the Reserva Particular do Patrimônio Natural-Feliciano Miguel Abdala, Minas Gerais, Brazil. A total of 2,727 10 min focal subject samples were collected on 32 adult females and 31 adult males between April 2007 and March 2008. Compared with males, females spent a significantly lower proportion of their time in proximity to other group members and gave staccatos at significantly higher rates while feeding, resting, and traveling. Conversely, males emitted neigh vocalizations at significantly higher rates than females when feeding and resting only. Both sexes gave significantly more staccatos when feeding than when they were engaged in other activities, but their respective rates of neighs did not vary across activities. Both females and males emitted staccato vocalizations at significantly higher rates during times of the year when preferred foods were scarce, but no seasonal differences in the rates of neigh vocalizations were observed in either sex. Females and males showed a reduction in the number of neighbors following staccato vocalizations and an increase in the number of neighbors following neigh vocalizations. Our findings of sex differences in the rates of staccato and neigh vocalizations and the effects of these vocalizations on interindividual spacing are consistent with sex differences in spatial dynamics, and confirm the role of vocal communication in mediating spatial associations in this species.

Vocal sequential exchanges and intragroup spacing in the Northern Muriqui Brachyteles arachnoides hypoxanthus.

Sequential exchanges of vocalizations (staccatos and neighs) emitted by Northern Muriquis Brachyteles arachnoides hypoxanthus were recorded at the Biological Station of Caratinga, Minas Gerais State, Brazil. Staccatos and neighs containing larger proportion of short elements were preferentially produced during short-range exchanges; neighs, produced by a larger number of participants, were typical of long-range exchanges. Staccatos emitted by animals feeding in a dispersed manner contained a larger proportion of tonal elements than those emitted by muriquis feeding in a cohesive manner. Sequential exchanges seem thus to be constituted by two inter-related subsystems of calls that aid muriquis to coordinate intragroup spacing, despite the poor visibility of the habitat.

Vocal sequential exchanges and intragroup spacing in the Northern Muriqui Brachyteles arachnoides hypoxanthus

Intercâmbios seqüenciais de vocalizaçäes (estacados e relinchos) emitidos por Muriquis-do-norte Brachyteles arachnoides hypoxanthus foram registrados na Estação Biológica de Caratinga, em Minas Gerais. Os estacados e os relinchos compostos de grande número de elementos curtos eram principalmente emitidos nos intercâmbios a curta distância; os relinchos, produzidos por um maior número de participantes, eram típicos dos intercâmbios a longa distância. Os estacados de animais que se alimentavam de modo disperso continham maior proporção de elementos tonais do que os emitidos por muriquis que se mantinham agrupados durante a alimentação. Os intercâmbios seqüenciais parecem, assim, constituídos de dois subsistemas de chamados através dos quais os muriquis conseguem coordenar o espaçamento intragrupal, apesar da baixa visibilidade do ambiente.