These vocal primates are the biggest of all the New World monkeys. Unlike Old World monkeys, howlers and other New World species have wide, side-opening nostrils and no pads on their rumps.

There is no single species of monkey, there are hundreds of them divided into Old World Monkeys and New World Monkeys. Some ...

Photo by Mark Beech The discovery, announced in the current issue of Proceedings of the National Academy of Sciences, USA, is providing important clues as to when and how old world monkeys ...