The
American red squirrel (
Tamiasciurus hudsonicus) is one of three species of
tree squirrel 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). American red squirrels are also referred to as
pine squirrels,
North American red squirrels,
boomers, and
chickarees. They are medium-sized (200–250 g)
diurnal mammals that defend a year-round exclusive territory. The diet of these tree squirrels is specialized on the seeds of
conifer cones. As such, they are widely distributed across
North America wherever conifers are common, except on the Pacific coast, where they are replaced by Douglas squirrels. Recently, American red squirrels have been expanding their range to include primarily hardwood areas.