The White-tailed, or Virginia, deer is the most common deer in the United States. It ranges from coast to coast, southward from southern Canada to northern South America. Those found in the north are the largest, measuring four feet (1.2 m) at the shoulders and weighing 200 to 400 pounds (90 to 180 kg). The coat is shiny red in summer and blue-gray in winter. The underparts and tail are white.

White-tailed deer live alone or in groups of one male and two or three females. A swift runner and high jumper, the deer can reach 30 miles per hour (48 km/h) and can leap as high as eight feet (2.4 m). When running from danger, it holds its white tail erect.

This deer was important to American pioneers for food and clothing and is still the most commonly hunted game mammal in the United States. It is destructive to orchards.

The smallest deer in North America, the key deer, is a dwarf subspecies of the white-tailed deer. It stands about 25 inches (64 cm) tall at the shoulder and weighs about 50 pounds (23 kg) or less. It is endangered in the wild; a small population exists in the National Key Deer Refuge on Florida's Big Pine Key.

The hoofprint of a white-tailed deer is shaped like a heart. The deer’s hoof is cloven (KLOH vuhn), or divided. Each foot has two large, curved toes. The curves leave a heart-shaped print in the dirt when the deer walks.

Deer use their hoofs for running quickly. But they also use them to signal danger. When a female senses trouble, she stomps her hoof hard on the ground. This tells other deer in the herd to run away.

Deer can run extremely fast. Their legs are long, thin, and light in weight. Running on their hoofs gives deer extra speed and bounce. Deer can usually outrun their enemies. A white-tailed deer can run up to 40 miles (64 kilometers) an hour. It can leap up to 20 feet (6.1 meters) in a single jump.

The white-tailed deer is Odocoileus virginianus; key deer, O. v. calvium.