Distribution of rhesus macaques (Macaca mulatta) in Bangladesh: Inter-population variation in group size and composition

Abstract

In Bangladesh rhesus macaques (Macaca mulatta) are found in forested habitats and urban areas. From 2005 to 2010, we investigated the distribution of rhesus macaques throughout the country. Populations were estimated by line transect, point sampling and direct counting. A total of 37 groups in 16 localities were recorded in urban areas. Overall, group size in urban areas ranged from 22 to 91 individuals, with a mean of 41.3 ± 16.7. Rhesus macaques in urban areas were found mostly near Hindu communities. Nearly five times as many groups (n= 176) of rhesus were observed in the forested habitats of the country. Overall group size in natural habitats varied from 10 to 78 individuals, with a mean of 30.2 ± 10.9. Of the natural habitats, the northeast rainforests were found to support the largest groups (38.9 ± 10.3, n = 49), while smaller groups were found in the central deciduous forests (19.3 ± 4.7, n = 18). The adult sex ratio was higher (1 male to 2.86 females) and the ratio between adult and non-adult (immature) was lower (1 adult to 1.70 non-adults) in natural habitats than was found for the populations in urban areas (1 male to 1.93 females, and 1 adult to 2.11 non-adults). In urban areas, the human-monkey conflict is increasing as competition for resources intensifies.