There are more than 260 species of Monkeys found in the world today. They are derived from early primates that have been around for millions of years. There isn’t enough information about evolution to say with certainty how they came to be. The gibbon monkey — or, more properly, gibbon ape — might not have a familiar name, but you’ve probably seen his funny walk and graceful style of swinging through the trees. Gibbons are so closely related to humans that they live in monogamous families and can walk upright on two legs. These slender, agile primates live in a small part of the world and are on the endangered species list.