Primates Final Essay A New world monkeys are found in the tropics of South and Central America, and the old world monkeys are found in the tropics and in various habitats in Africa and Asia. New world monkeys are only found in arboreal habitats, their diet consists mainly of fruit. Old world monkeys are found in various habitats, such as the savanna, rainforest and mountains. Most old world monkeys spend their days on the ground instead of the trees and their diets range greatly. Old world monkey females swell when in heat, and most groups are one male and lots of females. New world monkeys sometimes just have one male, but there tends to be more pairing, which means more than one male in most groups, they also all have scent glands that they use for marking territory and for attracting a partner. There are lots of anatomical biological differences between new and old world monkeys. I will start at the head and end at the tail. New world monkeys are platyrrhine, or flat-nosed. Their nostrils also open away from the center and are far apart in comparison to old world monkeys. Old world monkeys are catarrhine, or downward facing nosed. Their nostrils are closer together and open downward or forward, never to the sides like new world monkeys. Old world monkeys have 2 premolars, and the premolar in the mandible is sectorial. New world monkeys have three premolars and they tend to be larger in size compared to the size of the animal although the last molar is small or nonexistent. The tympanic membrane on new world monkeys is connected by a bony ring to the outer ear, whereas on old world monkeys it is connected by a bony tube. One of the most defining differences lies in the digits. Thumbs on new world monkeys are in the same line as the rest of the digits, whereas old world monkeys have rotated, opposable