There are two main groups of squirrels - ground squirrels that burrow and nest in the ground, and tree squirrels that nest in trees. Tree squirrels include eastern gray squirrels, fox squirrels, and red squirrels. They live in forested areas for protection from predators and store food for winter. Red squirrels are small with reddish fur and eat pine seeds and other foods. Chipmunks are solitary except during mating and store food in their cheeks for modified hibernation when they stay semi-awake.