Any of 10 species of long-tailed, essentially thumbless African Old World monkeys in the genus Colobus (family Cercopithecidae).
Colobus monkeys are diurnal, generally gregarious vegetarians. They make long leaps from tree to tree. The four species of black-and-white colobus are 22–24 in. (55–60 cm) long, excluding the 30–32-in. (77–82-cm) tail. They are slender and have a long, silky coat. The five species of red colobus are brown or black with red markings and are 18–24 in. (46–60 cm) long, excluding the 16–31-in. (40–80-cm) tail. The olive colobus has short, olive-coloured fur. Several races of red colobus are considered endangered; other colobus species are vulnerable or rare.