The purple-faced langur is a folivorous species, but it will also consume fruit, seeds, and cultivated crops such as Eucalyptus . This species prefers immature leaves to more mature ones because they are high in protein and low in lignin. Group sizes range from 2 to 20 individuals. This is a diurnal and an arboreal species. The purple-faced langur has a unimale social system.
Males migrate from their natal group near the time of puberty.
This is a territorial species and will defend its territory against conspecific groups, and females tend to be more aggressive than males in these encounters. The purple-faced langur gives birth to a single offspring. Burton, F. 1995. The Multimedia Guide to the Non-human Primates . Prentice-Hall Canada Inc. Estes, R.D. 1991.