Preliminary observations on habitat utilization and diet in eight Surinam Monkeys.

The eight monkey species occurring in Surinam were studied in the Raleigh-vallen-Voltzberg Nature Reserve along the Coppename River. Special emphasis was placed on determining how these eight species divide up available habitat and food resources within a 300-ha study area. Cebus apella apella is probably the most adaptable of the Surinam monkeys. It was found mainly in the understory and lower to middle parts of the canopy of all five forest types (high rain forest, low rain forest, mountain savanna forest, liane forest, pina swamp forest) in the study area, and entered a variety of edge habitats. Saguinus midas midas, the only callitrichid in Surinam, also occurred mainly in the understory and lower to middle parts of the canopy of all five forest types, but was the only species to spend more time in edges than in non-edge habitats. Alouatta seniculus was most often seen in the middle to upper strata of high forest, but occasionally entered the four other forest types and a variety of edges. Cebus nigrivittatus is apparently less adaptable than its congener and was largely restricted to the understory and lower to middle strata of high forest. It occasionally entered two other forest types as well, but was rarely seen in edges. Chiropotes and Pithecia were both found almost exclusively in high forest and mountain savanna forest, but Chiropotes was mainly in the upper part of the canopy and in emergents, whereas Pithecia occupied the lower to middle parts of the canopy and the understory. Neither species made much use of edges. Ateles paniscus paniscus and Saimiri sciureus represent the extremes of primate adaptation in the Voltzberg area. Ateles was the most restricted species, and was found almost exclusively in high forest. It very rarely entered edges and was most often seen in the uppermost forest strata. In contrast, Saimiri was the only species that was not found most often in high forest, and it occurred consistently lower than any other monkey in the area. More than 50% of all Saimiri observations were in liane forest, a habitat rarely or never entered by most of the other species, and more than 60% were in the understory stratum. Saguinus, Saimiri, Cebus apella and C. nigrivittatus were omnivorous, with Saimiri apparently eating the most arthropods. The four remaining species were not seen feeding on insects or other animals. All eight species included a high proportion of fruit in their diet, with flowers and sometimes leaves usually playing a minor role. The two largest species, Alouatta and Ateles, were the most folivorous, but Alouatta was the only one that ate mature leaves and its leaf intake far exceeded that of Ateles. The three smallest species (Saguinus, Saimiri, Pithecia) did not eat leaves at all. Chiropotes was an important seed predator; Pithecia and C. Nigrivittatus may also depend heavily on seeds. Alouatta and Saimiri were never seen acting as seed predators. Alouatta and Ateles were major seed dispersers. The other six species occasionally dispersed seeds, but to a much lesser extent.

Callitrichids in Brazil and the Guianas: current conservation status and potential for biomedical research.

Brazilian and Guianan callitrichids are categorized as endangered, vulnerable, common or status unknown. Endangered species should not be used in biomedical research and a continuing supply of wild-caught vulnerable species is also out of the question. Common species, on the other hand, could withstand limited sustained yield cropping without difficulty. Species categorized as status unknown should not be used until more data on them become available. Callitrichids have a higher reproductive potential than other New World monkeys, are for the most part quite adaptable, and are rarely hunted for food or captured as pets locally. Widespread habitat destruction is the major threat to their survival and species with naturally small ranges in areas of high human activity (e.g. Leontopithecus, Callithrix flaviceps) are in the greatest danger.