A preliminary study on the social relationships in a semi-free ranging colony of sun-tailed monkeys (Cercopithecus solatus), a species recently discovered in Gabon.

In 1984, a species of guenon endemic to Gabon was discovered: the sun-tailed monkey (Cercopithecus solatus). This species is difficult to locate and observe in the wild, and hence to date has been little studied. The Centre International de Recherches Medicales de Franceville (CIRMF), Gabon, houses the world's only breeding colony of C. solatus, on which eco-ethological investigations can be carried out in a semi-free ranging environment. The data reported here present the first results of observations on the social relationships of this colony and support the scant field observations available on this species, showing a basic social unit of one adult male and several females with their offspring. The resident male systematically repulses any second adult male in proximity to the group. A clear hierarchy exists among the females, with mature female offspring eventually acquiring a rank just below that of their mother.