It also comprises forty percent of all present day mammal species. There are over 365 species of squirrels in seven families. They include the tree squirrel, ground squirrel, and flying squirrel. Plus many squirrel-like mammals such as the gopher, ground hog and prairie dog.
Squirrels are the most active in late winter, when the mating season begins.
The males will chase a females, as well as, chase off other suitors. This ritual of chasing, occurs through the trees at top speed. While they perform some of the most breathtaking acrobatics imaginable. The period of gestation varies from 33 days in the smaller species of pine squirrels, up to 60 days for the larger species such as the common gray and fox squirrels. Squirrels are usually born in the early spring.