1. Not All Primates Are Monkeys
The term "monkey" is sometimes used as a catch-all for every animal in the primate family, but the truth is that monkeys live on completely different branches of the evolutionary tree from both apes (i.e., chimpanzees, gorillas, and humans) and prosimians (i.e., lemurs, tarsiers, and lorises).
One big difference between monkeys and other primates is in the tail: Most monkeys have tails, while apes and other primates do not. Apes also tend to be larger than monkeys and, thanks to their larger brains, more intelligent.
Only New World Monkeys Have Prehensile Tails
Only New World monkeys in the Atelidae family, like howler monkeys and spider monkeys, and capuchins in the Cebidae family, have prehensile tails. These arboreal primates live in the tropical regions of Mexico, Central America, and South America. Old World monkeys, which live in Asia and Africa, have tails, but they are not prehensile.
In length and gripping ability, spider monkeys and howler monkeys have an edge on capuchins. Spider monkeys have tails that are longer than their entire bodies. Their tails are also hairless and have friction pads for better gripping.11 Capuchins, which have hair-covered tails that are not nearly as long, primarily use their tails to grasp branches and carry fruit through the forest.
