By doing so these Monkeys had to adapt to a new environment. New World Monkeys are monogamous in their pairing and care for the young together. 3 Answers. Ancestors of the Spider Monkey fall into the Pleistocene group of species. Do they even grow like human fingernails and toenails? New world monkeys are small-to-medium, up to 10 kg. The New World Monkeys are divided into five main families: – Cebidae which include capuchin and squirrel monkeys 0 3 0. 10 years ago . Another exception is the spider and howler monkeys— New World species with nails like Old World monkeys (2). I have never seen pictures of wild Apes and Monkeys that have had their nails growing past the tips of their fingers. Many are small, arboreal and nocturnal, so our knowledge of them is less comprehensive than that of the more easily observed Old World monkeys. B) New World monkeys have enhanced depth perception. Favorite Answer. New world primates and the prosimians have claws, old world primates including apes have nails. Old World monkeys have two premolars that have sharp cusps. Like the indris of Madagascar, they have developed the unusual habit of defending territory in the top branches of their forest canopies with vocalizations. C) Old World monkeys are arboreal. Lv 6. Old World monkeys (Cercopithecidae) are a group of simians native to Old World regions including Africa, India, and Southeast Asia.There are 133 species of Old World monkeys. Another exception is the spider and howler monkeys— New World species with nails like Old World monkeys (2). Capuchins have nails and “the most dexterous hands of any new world monkey, with functionally (but not fully) opposable thumbs, allowing them to grasp and manipulate objects”. The nails are present on all digits in all primate species. The howler is the largest of the New World monkeys. Like other Old World monkeys, baboons do not have prehensile (gripping) tails. New world monkeys' nostrils have a wide septum and they face outward. New World (platyrrhine) and Old World (catarrhine) monkeys are distinguished by the form of the nose. (LaZoo, 2011) Grasping objects can be very useful for obtaining food with a hard outer layer. Old World monkeys are most quickly differentiated from New World monkeys by looking at their tails. Let me know if you know. Old World Monkeys all have nails, I'm pretty sure. 10 years ago. Answer Save. They spend much of their time on the ground. Old world monkeys have a narrow septum and their nostrils face forwards. How do New World monkeys differ from Old World monkeys? Other monkeys do not have the use of this “third hand” as their tails are either short or non-prehensile. Login to reply the answers Post; Anonymous. New World monkeys have broad noses with a wide septum separating outwardly directed nostrils, whereas Old World monkeys have narrow noses with a thin septum and downward-facing nostrils, as do apes and humans. The new world monkeys have a diversity of diets, habits, and social systems. But they can and do climb trees to sleep, eat, or look out for trouble. Thank you! Most New world monkeys have long, often prehensile tails. Not all of them appear to have teeth that seem fit to bit them. Fossil remains dating millions of years ago show that they were once in Cuba and Spain. Old World monkeys have fingernails and toenails, while New World monkeys often have claws on all of their digits with the exception of the big toes of marmosets and tamarins (2,3).