The standard metabolism of A. trivirgatus (night monkey, owl monkey) is 22.5-46.2% below Kleiber''s curve for mammals, which applies to other cebid monkeys like Saimiri sciureus and Alouatta. However the metabolic rate of Aotus is not reduced to the extent found in 2 hypometabolic prosimians Perodicticus potto and Nycticebus coucang. The low metabolism in Aotus is associated with a normal body temperature and a thick fur of high insulating power.