A primate (/ˈpraɪmeɪt/ PRY-mayt) (from Latin primat-, from primus 'prime, first rank') is a eutherian mammal constituting the taxonomic order Primates (/praɪˈmeɪtiːz/). Primates arose 85–55 million years ago first from small terrestrial mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, a shoulder girdle allowing a large degree of movement in the shoulder joint, and dextrous hands. Primates range in size from Madame Berthe's mouse lemur, which weighs 30 g (1 oz), to the eastern gorilla, weighing over 200 kg (440 lb). There are 190–448 species of living primates, depending on which classification is used. New primate species cont