The lion-tailed macaque weighs 7 - 15 kg (15 - 33 lb). It is found in tropical evergreen forest, where it is omnivorous (eat both plant and animal life) and diurnal (active during daylight hours) and primarily arboreal. (animals that live in trees) Groups of lion-tailed macaques range from 4 - 34 individuals. They usually contain about 10 - 20 individuals, including 1 - 3 adult males.
The lion-tailed macaque has never been common. By 1971 it was known to occur only in the southern third ofIndia, generally in the Western Ghats. In 1984 it was thought to occur in scattered locations in Karnataka, Kerala and Tamil Nadu. The major reason for its decline appears to have been habitat loss due to the spread of agriculture and teak, coffee, tea and other plantations. Formerly it was extensively captured for the pet trade, zoos and research, as well as for use in Oriental medicine.