Red-backed squirrel monkey  (Saimiri oerstedii)

This small monkey has a slender body and a tail that is longer than the body itself. The tail is not prehensile, but it does aid in balance as this monkey leaps between branches in a squirrel-like fashion. The limbs are fairly long and slender, and the thighs are shorter in relation to the lower leg than in species that clamber, such as howler monkeys. This adaptation allows squirrel monkeys to exert more force when jumping and so they can propel themselves further (4). This monkey’s fur is short, thick and yellow brown in colour, with the underside being a paler yellow. As its common name, the red-backed squirrel monkey suggests, this primate has red-coloured fur on its back (5). It also bears a distinctive crown on its head; in the black-crowned subspecies (Saimiri oerstedii oerstedii), this crown is, as the name suggests, black, whereas in the grey-crowned Central American squirrel monkey (Saimiri oerstedii citrinellus) it is agouti in the male, and blackish-grey in the female (2) (4). Males and females are similar in appearance, though males are slightly larger in size. During the breeding season males also become ‘fatted’, with a noticeable increase in size around the neck and shoulders (4).