The red squirrel is a rather small-sized tree squirrel, only about half the size of the more common gray squirrel. It's bushy tail is somewhat slender and almost as long as the length of its head and body combined. The coat of the red squirrel is a rusty, reddish-brown in summer, turning slightly grayer in winter, and the underside is white. In summer, a black stripe is pronounced along its sides, separating the white underside from the reddish, upper body. Both males and females are about equal in size. Red squirrels are active year-round but will take shelter during harsh weather. In the fall, red squirrels will store their food for the winter in large underground caches. Sometimes they will bury their food at random just as the gray squirrel does. Red squirrels are also known to tap sugar maple trees to harvest the sugar in the sap. They actually bite into the tree trunk to puncture the sap-carrying "vessel" (xylem), leave the tree to allow time for the water in the sap to evaporate, and come back to harvest the syrup remaining on the trunk and branches. Red squirrels are unsociable, highly territorial, and aggressive. They will not tolerate their own or other squirrel species in their territories. They can also be very noisy and are sometimes nicknamed "chatter boxes."