Survey and Status of the Muriquis Brachyteles Arachnoides in the Serra Dos Órgãos National Park, Rio De Janeiro

Th e Serra dos Órgãos National Park protects 11,800 ha of Atlantic forest in the state of Rio de Janeiro (22°30'S, 43°06'W; 300 to 2,263 m above sea level). Vegetation types include montane dense evergreeen forest up to altitudes of 1,800 m; cloud forest from 1,800 to 2,000 m; and high altitude grassland above 2,000 m. Th is paper reports on surveys carried out in 10 localities in the park specifi cally to obtain a minimum estimate of the population of northern muriquis (Brachyteles arachnoides). Muriquis were sighted 26 times at altitudes ranging from 800 to 1,500 m. It is possible that they belonged to four groups in which case the minimum number of individuals recorded would be 56. If in fact the sightings were of just two groups, the minimum number of individuals would be 32. Black-horned capuchin (Cebus nigritus) and brown howler monkeys (Alouatta guariba) were also recorded for the park. Th e buff y-tufted-ear marmoset (Callithrix aurita) was not seen.