Udzungwa red colobus  (Piliocolobus gordonorum)

The Udzungwa red colobus lives in multi-male/multi-female groups of anything between 7 and 83 individuals, but usually of around 24 (2) (7). Those groups in highly degraded forests where food is scarce are thought to adopt a system of fission-fusion society, in which the larger troop breaks up into smaller groups to forage (7). This diurnal species (8) feeds mainly on leaves, but will also eat flowers, fruits and fungus (2) (6). The peculiar behaviour of geophagy (eating of soil) has occasionally been observed, which is thought to assist digestion in a similar way to charcoal consumption by other animals (6) (9). Udzungwa red colobus are preyed upon by crowned hawk-eagles and chimpanzees. When a predator has been spotted, these monkeys alert others in the group through a series of calls, which differ to indicate either an aerial or ground predator (2).

Information is rather scant on the reproductive biology of this monkey. Males attain sexual maturity at around four and a half years of age, and females at about four, after which females are known to have a substantial pink sexual swelling during oestrous. After birth, parental care is performed solely by the mother, who carries the infant on her belly for the first three months (2).