The Whitetail Deer is the most common deer species in North America. With an estimated 30 million deer, the inhabit all of central and eastern United States, up into Canada, and down into Mexico. Whitetail Deer are so popular, they are the state animal of 9 different states, Arkansas, Illinois, Michigan, Mississippi, New Hampshire, Ohio, Pennsylvania, South Carolina, and Wisconsin. When it is alarmed or threatened, it runs with its white under tail upward, which gives it its name. During the spring, they start growing their antlers, and can grow more than an inch per day in captivity.