The mexican Hairless, better known as the Yucatan:

72151_195700907221054_1697712224_nYucatan pigs are mostly distinguishable by their lack of hair (although they may have sparse whiskers). These pigs are native to south Mexico, Costa Rica, and other Latin American countries. The first import was of 25 animals brought to the United States in the 1960’s. These were bred by Colorado State University as research animals. They are black or slate grey with a short profile and short snout. They have dark pigmented skin, although some lines have been developed with light colored skin for use in dermatology studies. They are very docile and easy to care for. These pigs have been fully pedigreed, are closed to outside breeding, and are used only for research. They average 75-150lbs.