The American red squirrel (Tamiasciurus hudsonicus) is one of three species of tree squirrels currently classified in the genus Tamiasciurus, known as the pine squirrels (the others are the Douglas squirrel, T. douglasii, and Mearns's squirrel, T. mearnsi). The American red squirrel is variously known as the pine squirrel, North American red squirrel and chickaree. It is also referred to as Hudson's Bay squirrel, as in John James Audubon's work The Viviparous Quadrupeds of North America (hence the species name). The squirrel is a small, , diurnal mammal that defends a year-round exclusive territory. It feeds primarily on the seeds of conifer cones, and is widely distributed across North America wherever conifers are common, except on the Pacific coast, where its cousin, the Douglas squirrel, is found instead. The American red squirrel is not found on most of the Great Plains or in the southeastern United States, except for the Blue Ridge Mountains, as conifer trees are not common in those areas.