Chironectes

The water opossum (Chironectes minimus), also locally known as the yapok (/ˈjæpɒk/), is a marsupial of the family Didelphidae. It is the only living member of its genus, Chironectes. This semiaquatic creature is found in and near freshwater streams and lakes from Mexico through Central and South America to Argentina and is the most aquatic living marsupial (the lutrine opossum also has aquatic habits). It is also the only living marsupial in which both sexes have a pouch. The thylacine, commonly referred to as the Tasmanian tiger, also exhibited this trait but is now believed to be extinct. The animal lives in bankside burrows, emerging after dusk to swim and search for fish, crustaceans and other aquatic animals, which it eats on the bank. The local name for the water opossum, 'yapok', probably comes from the name of the Oyapok River in French Guiana. The yapok is a small opossum, 27-32.5 cm long, with a 36–40 cm long tail. The fur is in a marbled grey and black pattern while the muzzle, eyestripe, and crown are all black. A light band runs across the forehead anterior to the ears, which are rounded and naked. There are sensory facial bristles in tufts above each eye as well as whiskers. The animal's tail, furred and black at the base, is yellow or white at its end. The hindfeet of the yapok are webbed, while the forefeet ('hands') are not. The forefeet can be used to feel for and grab prey as the yapok swims, propelled by its tail and webbed back feet. Unlike other didelphids, the water opossum does not have a cloaca.