Squirrels forage for food about four to six hours a day just after dawn and before dusk, with the remainder of the day spent lounging or sleeping. Squirrels don’t hibernate, but do stay in their nests during heavy bouts of winter weather. On cloudy days, or during courtship, they may spend more hours up and about. Squirrels are as agile on the ground as they are among the tree canopies of the forest. They use their very sharp claws for grabbing a hold of bark and their long tails for breaking leaps and balance. Their bodies can twist and turn on a dime atop thin branches. When frightened, they freeze and flatten their tail and body against a tree trunk or branch, inching around the circumference of the tree or branch to avoid predators. Squirrels have even been known to swim across lakes.