Lemurs first evolved 50-60 million years ago. Experts say they likely arrived in the area by dispersal, perhaps washed from Africa to Madagascar on floating vegetation. Lemur catta is the only species of genus Lemur but they share the Lemuridae family with many others. Their closest relatives are the gentle lemurs (golden bamboo lemur, grey gentle lemur, and broad-nosed gentle lemur). They belong to the order Primate and the suborder Strepsirrhini. Strepsirrhini split from other primates ~63 million years ago. Ring-tailed Lemurs have fingernails, toenails, and opposable thumbs- adaptations for a life in trees. They share unique dental characteristics with the family Lemuridae- specialized teeth in their lower jaw that form a dental comb, thought to aid in grooming.