Around 40 million years ago in the world's ancient tropical forests, the first monkeys existed. Monkeys are still found across the tropics today, that are the ancestors of even larger primates like forest apes (and therefore humans). There are currently 310 different species of monkey in the world, 95 of which are endemic to Brazil.
Monkeys (along with humans) are primates, and therefore belong to one of the most intelligent animal groups on Earth. In their natural habitats, countless monkey species display complex social behaviours in their daily lives from living in groups and caring for young, to the use of basic tools to get food.
Pygmy Marmosets are the world's smallest monkeys but with the aid of their 3D eyes, have cleverly learnt to farm sap, which they wait patiently for after making a hole in the tree. Other monkey species have even learnt to communicate between one another, almost functioning as one monkey troop between the canopy layers.
One of the most well-known clever monkeys is the White-Faced Capuchin native to South America. They are known to fight other monkeys for their friendship, killing more of their own than any predator. White-Faced Capuchins also seem to become excited by plants, particularly those with antiseptic properties, which they rub themselves with.
It is generally thought that the cleverest monkeys are found in the largest groups (in the same way as our towns and cities), like the Gelada found in Africa. Groups of more than 800 females and their young, reside together on the Ethiopian mountains guarded by a number of males. The intelligence of monkeys however, does mean that they have to deal with similar social problems to us.