They are also the noisiest tree squirrels and scold, squawk, and sputter at other squirrels and at humans. One tree squirrel is called a flying squirrel. Flying squirrels glide from tree to tree, instead of jumping like other squirrels. They are the only nocturnal squirrels. That means they stay awake at night and sleep in the daytime.
Tree squirrels spend most of their lives in trees.
They race along branches, leap from tree to tree and go up and down, down and up, the tree trunks. Tree squirrels build nests in tree trunk holes or high up in the branches. Here they sleep, stay out of bad weather, and raise their young. Many squirrels live in burrows under the ground instead of in the trees. They look a lot like tree squirrels, except their tails are often smaller and less furry.