Behavioral flexibility of a group of bearded capuchin monkeys (Cebus libidinosus) in the National Park of Brasília (Brazil): consequences of cohabitation with visitors / Flexibilidade comportamental de um grupo de macacos-prego (Cebus libidinosus) no Parque Nacional de Brasília (Brasil): conseqüências da convivência com os visitantes

Increasing urbanization and deforestation have enhanced the opportunities of contact between humans and monkeys and the impact of human activities on primate behavior is receiving growing attention. This study explores whether activity budgets and diet of a group of capuchin monkeys (Cebus libidinosus) inhabiting the area of the swimming pools of the National Park of Brasília is affected by the presence of visitors providing food to them. During one year, both in the dry and the wet seasons, we scored capuchins' behavior via scan sampling every ten minutes. Results showed that this group spent less time foraging for wild foods than other comparable groups living in similar habitats. Moreover, capuchins relied more on human food during the dry season, when pulpy fruits were less available, than in the wet season. Our findings confirm other studies on different monkey species that have shown that access to human food decreases the time spent foraging for wild food and the home range size. They also show that capuchins are able to modify their diet, to exploit alternative food sources, and to change their activity budget in response to the availability of new food opportunities and to seasonal food availability.

Recentemente, o impacto de atividades humanas sobre o comportamento de primatas tem recebido maior importância dado o crescente desmatamento e urbanização, que têm favorecido o aumento do contato entre humanos e macacos. O presente estudo descreve os padrões de atividade e a dieta de um grupo de macacos-prego (Cebus libidinosus) que vive no Parque Nacional de Brasília. O Parque é freqüentado diariamente por visitantes, de modo que os animais estão habituados à presença humana, bem como ao consumo de itens de sua dieta. Observações comportamentais do grupo foram realizadas ao longo de um ano, compreendendo a estação seca e a chuvosa, utilizando-se registro de varredura a cada 10 minutos. Resultados obtidos indicaram que o grupo despendeu menos tempo forrageando itens naturais do que outros grupos vivendo em habitats similares. Além disso, durante a estação seca, quando há menor disponibilidade dos frutos de polpa, os macacos-prego alimentaram-se mais de itens da dieta humana como uma fonte alternativa de recurso. Como demonstrado em estudos anteriores realizados com outras espécies de macacos, a alimentação baseada em itens da dieta humana pareceu diminuir a motivação dos animais para forragear no seu habitat natural, assim como promoveu a redução do tempo gasto no forrageamento e a redução de sua área de uso. Nossos resultados indicaram ainda que o consumo de comida humana reflete o caráter adaptável dos animais em explorar fontes alternativas de recurso, bem como a sua habilidade em modificar a sua dieta e padrões de comportamento face às mudanças ambientais.

An experimental analysis of ingestion rates in an omnivorous species.

Food intake is difficult to estimate under natural conditions. We investigated ingestion rates of 14 different food types in 26 captive capuchin monkeys (Cebus apella). The procedure consisted in weighing a piece of food and using a two alternative choice tests to present food to the subject, alone in its cage. We recorded the food chosen and the time it took the subject to consume the food entirely. Consumption time was converted into ingestion rates (g/s) for each food type. Ingestion rates of food types significantly differed, and the difference was significantly higher among foods than among subjects. In particular, ingestion rates of the fruits were higher than those of human-processed food. Interestingly, food preferences were significantly related to energy intake rate, i.e., to the amount of energy ingested per unit of time, but not with ingestion rates or energy content alone. The energy acquired by eating different types of food cannot be calculated on the basis of the time spent eating unless a correction factor for each given food (or similar ones) is applied. Future controlled studies should provide field researchers with such corrections factors, possibly using foods collected in the wild.

Behavioral flexibility of a group of bearded capuchin monkeys (Cebus libidinosus) in the National Park of Brasília (Brazil): consequences of cohabitation with visitors.

Increasing urbanization and deforestation have enhanced the opportunities of contact between humans and monkeys and the impact of human activities on primate behavior is receiving growing attention. This study explores whether activity budgets and diet of a group of capuchin monkeys (Cebus libidinosus) inhabiting the area of the swimming pools of the National Park of Brasília is affected by the presence of visitors providing food to them. During one year, both in the dry and the wet seasons, we scored capuchins' behavior via scan sampling every ten minutes. Results showed that this group spent less time foraging for wild foods than other comparable groups living in similar habitats. Moreover, capuchins relied more on human food during the dry season, when pulpy fruits were less available, than in the wet season. Our findings confirm other studies on different monkey species that have shown that access to human food decreases the time spent foraging for wild food and the home range size. They also show that capuchins are able to modify their diet, to exploit alternative food sources, and to change their activity budget in response to the availability of new food opportunities and to seasonal food availability.