The usual words for monkeys in Pali are kapi, makkata and vanara. These words seem to be used loosely and interchangeably in the Tipitaka as is suggested by the mention of a large black-faced monkey, a clear reference to the Hanuman Langur, and a small red-faced monkey, a reference to the Rhesus Macaque. In both cases the word makkata is used (Ja.II,445). However, many of the numerous stories about monkeys in the Jatakas would seem to refer mainly to the macaque because this monkey would have been more familiar to most people and because of its more human-like appearance and often amusing antics. Monkeys pull faces and threaten people (Ja.II,70) and while moving through the forest they grab a branch and let go of it only to grab another (S.II,95; Sn.791). Hunters used to go into the forests of the Himalayan foothills and set traps of sticky pitch to catch them. The more curious monkeys would touch the pitch, get stuck and while trying to free one paw would get their other paws stuck. The hunters would then kill them, put the carcass on a spit and cook them over a fire (S.V,146).
The Tipitaka often uses the term monkey mind (kapicitta) to describe the agitated, easily distracted and incessantly moving behaviour of ordinary human consciousness (Ja.III,148; V,445). The Buddha said that a person with uncontrolled craving ‘jumps from here to there like a monkey searching for fruit in the forest.’ (Dhp.334). The monk Valliya compared the body to a five-doored house and the mind to a macaque racing around inside it. Then he cried to himself, ‘Be still, monkey, stop running. Things are not as they were before. Now you are restrained with wisdom.’ (Th.125-6). Maha Kassapa said that a monk who wears rag robes and yet is conceited, is like a monkey wrapped in a lion's skin (Th.1081). In a story meant to illustrate the idea that greed can make one blind to one's own benefit, the Jataka tells of a langur who lets go of all the beans it had just to retrieve one that it had dropped (Ja.II,74). Street entertainers had monkeys which were trained to play with snakes and to do tricks (Ja.III,198). According to the Jataka the Bodhisattva was often reborn as a monkey and throughout the Jataka stories monkeys are depicted as having the best and worst human traits and attitudes. And if you wish to know just how human-like monkeys can be in some ways have a look at this wonderful documentary.