The Jaguarundi (Puma yaguarondi) is a medium-sized Mexican, Central and South American wild cat: average length 65 cm (30 inches) with 45 cm (20 in) of tail. It has short legs and an appearance somewhat like an otter; the ears are short and rounded. The coat is unspotted, uniform in color, and varying from blackish to brownish gray (gray phase) or from foxy red to chestnut (red phase). The two color phases were once thought to represent two distinct species; the gray one called "Jaguarundi", and the red one called "Eyra". However, these are the same species and both color phases may be found in the same litter. Its coat has no markings except for spots at birth. This cat is closely related to the Cougar as evident by its similar genetic structure and chromosome count; both species are in the genus Puma although it is sometimes classified under a separate genus, Herpailurus and until recently, both cats were classified under the genus Felis.

In some Spanish speaking countries, the Jaguarundi is also called "Leoncillo", which means "little lion".