The average groundhog is 20 inches long and normally weighs from 12 to 15 pounds. Punxsutawney Phil weighs about 20 pounds and is 22 inches long.

 Groundhogs are covered with coarse grayish hairs (fur) tipped with brown or sometimes dull red. They have short ears, a short tail, short legs, and are surprisingly quick. Their jaws are exceptionally strong.

 A groundhog's diet consists of lots of greens, fruits, and vegetables and very little water. Most of their liquids come from dewy leaves.

 A groundhog can whistle when it is alarmed. Groundhogs also whistle in the spring when they begin courting.

 Insects do not bother groundhogs and germs pretty much leave them alone. They are resistant to the plagues that periodically wipe out large numbers of wild animals. One reason for this is their cleanliness.

 Groundhogs are one of the few animals that really hibernate. Hibernation is not just a deep sleep. It is actually a deep coma, where the body temperature drops to a few degrees above freezing, the heart barely beats, the blood scarcely flows, and breathing nearly stops.

 Young Groundhogs are usually born in mid-April or May, and by July they are able to go out on their own. The size of the litter is 4 to 9. A baby groundhog is called a kit or a cub.

 A groundhog's life span is normally 6 to 8 years. Phil receives a drink of a magical punch every summer during the annual Groundhog Picnic, which gives him 7 more years of life.