The population of hammer-headed bats, Hypsignathus monstrosus H. Allen, 1861, in the District of Plateau in Abidjan has been studied from August 2003 to July 2004. Vocalization recognition and roost counts of bats males have been used in order to identify mating calls sites and to determine the variations of population size. Results show that the hammer-headed bats have demonstrated a high preference for reproduction site dominate by Terminalia catappa L. (Combretaceae). The population size varied with the site, the tree species and season.
Among the variety of activities in which wild chimpanzees use tools, some of the most complex behaviors are seen during nut cracking. As studies of nut cracking have been limited to a few habituated groups of chimpanzees located in a specific area in Ta