A diurnal forest dweller, it spends nearly all its life in the trees. It lives predominantly in groups of 6 to 8 animals consisting of a male, several females, and their young. More recently it has been observed in monogamous pairings (particularly the Mentawai Langur), although this might be a reaction to the decrease of their habitat. The groups are hierarchically developed, with intergroup communication that is both vocal and postural.
The surilis' diet consists of leaves, fruits, and seeds. Its life expectancy is estimated at 20 years.