The RBINS mammal collection contains 63,000 specimens and includes significant osteological material (bones and skeletons). The best represented groups are bats, rodents, carnivores and primates. The Institute has type material for 27 species. The rodent collection was extended by RBINS biologist Xavier Misonne. Walter Verheyen built up the collection of fauna from Belgium and Papua New Guinea, and Jacques Verschuren put together a large collection of mammal specimens from Africa.