Published online by Cambridge University Press: 24 April 2009
When the author visited Nigeria in 1981 to look at forests on the lower Niger, there had been no reports for 15 years of the red-bellied guenon Cercopithecus erythrogaster, and only a single specimen of the olive colobus Procolobus verus was known from the country. He found surviving populations of both monkeys, but each is threatened by widespread, intensive hunting, and by habitat destruction. If effective measures are not taken to protect the guenon and its rainforest habitat, this species could become extinct, since it occurs only in southwestern Nigeria.