[3] Complex behaviours have also been observed in this species, including greeting rituals[2] and varying group sleeping patterns.

The word "colobus" comes from the Greek κολοβός (kolobós, "docked", "maimed") and refers to the stump-like thumb.

Their ruminant-like digestive systems have enabled them to occupy niches that are inaccessible to other primates: they are herbivorous, eating leaves, fruit, flowers, lichen, herbaceous vegetation and bark.

Colobuses are important for seed dispersal through their sloppy eating habits, as well as through their digestive systems.

Tougher leaves correlate negatively with ingestion rate (g/min) as they are costly in terms of mastication, but positively with investment (chews/g).

Cases of allomothering are documented, which means members of the troop other than the infant's biological mother care for it.

Allomothering is believed to increase inclusive fitness or maternal practice for the benefit of future offspring.

Many members participate in a greeting ritual when they are reunited with familiar individuals, an act of reaffirming.

[4] They are prey for many forest predators such as leopards and chimpanzees,[citation needed] and are threatened by hunting for the bushmeat trade, logging, and habitat destruction.

Individuals are more vigilant (conspecific threat) in low canopy, they also spend less time scanning when they are around familiar group members as opposed to unfamiliar.