The owl-faced monkey or Hamlyn’s monkey inhabits the Democratic Republic of Congo (previously known as Zaire), Rwanda (specifically in the extreme northwest part) and the extreme southwest part of Uganda. The reason the monkey is only found in these areas is that the region is surrounded by lakes, rain forests, a volcano range and rivers. This also makes it unlikely that the species will expand its territory further. Their primary habitat is in a dense bamboo forest at elevations that range from 2,950 – 15,000 ft (900 – 4,554 meters).

As for their physical appearance, there is one simple thing that describes them best: a face that looks like an owl. That’s why their common name is more widely used than their other name (Hamlyn’s monkey). The face features a vertical stripe which starts from its brow to the lip and to a horizontal stripe on their brow ridge, forming a “T”. These stripes can be in a range of light colors such as yellow cream to white.

Their darkest coat shade is found on their underbelly, arms and hind limbs where the fur is completely black. The backs of the adults have dark fur with olive grey highlights. The dark fur makes them undetectable to their predators in some settings. The fur is fine, long and dense.

As for the newborns, they feature a yellow-brown coat which later turns into black, gradually changing and darkening as they grow and reach their adult stage. Both the female and male Hamlyn’s monkeys have bare and blue-skinned genital regions and buttocks. The male’s genitalia are typically the brightest because of their reddish-pink penis and blue scrotum. But this bright coloring also changes as it enters into the adolescent stage, so it can be an indication of sexual maturity.

Owl-faced monkeys live in packs or groups with around 10 monkeys. Each group has its own dominant male. Males are larger than females and the average body length is about 20 – 26 inches (50 – 65 cm) and their average weight range from 15 – 22 lbs (7 to 10 kg). The females, on the other hand, feature an average body length of 16 – 21.5 inches (40 – 55 cm) and average weight range of 10 – 13 lbs (4.5 – 6 kg).

This species features a unique pair of feet and hands with long finger and toe bones. This helps them to get a strong grip and is quite helpful for traveling on wet bamboo.

The birthing season for this species is during the months of May to October, with pregnancy lasting 5 to 6 months. Typically, this monkey only gives birth to a single offspring but there are rare cases when twin births happen. Births have a 2-year interval between them. Offspring are born with cute pink faces, which typically darken as they grow.