Black-tailed deer are found from central California to Alaska. Columbian black-tailed deer (Odocoileus hemionus columbianus) and Sitka black-tailed deer (Odocoileus hemionus sitkensis) are subspecies of mule deer (Odocoileus hemionus). They're smaller and darker than mule deer and white-tailed deer (Odocoileus virginianus).
Black-tailed deer are reddish-brown in summer and brownish-gray during winter. Their large ears move independently. The deers' broad tails are completely black or dark brown on top, and white underneath. They raise their tails to expose the white underside when they're frightened. Bucks have dark brown antlers with symmetrical branching. Columbian black-tailed deer have stocky bodies and long, slim legs. Does weigh up to 130 pounds, and bucks can weigh 200 pounds. Sitka black-tailed deer are smaller; does weigh about 80 pounds and bucks are about 120 pounds.
Black-tailed bucks have antlers, females don't. Male fawns begin growing antler buttons at 6 to 8 months old. These become full-size antlers in four to five years. Their antlers develop under a layer of skin called velvet. The velvet dries up and peels off once the antlers have fully developed. Shed annually, between December and March, antlers wind up on the forest floor, providing a source of calcium for other animals. New antlers appear between April and August. They become bigger and have more branches each year.
Black-tailed deer live in forested mountains and foothills of the Pacific coast. The climate is mild, having cool temperatures and abundant rainfall. Black-tailed deer typically spend their entire lives in areas that measure less than 3 square miles. They don't migrate, but mountain-dwellers often seek lower elevations during winter. Columbian black-tailed deer are seen from California to British Columbia; Sitka black-tailed deer live in Alaska.
Black-tailed deer feed along tree-line edges, where they can disappear into the forest if they're threatened. Ruminants, they have four stomachs. Barely chewed food is swallowed, then regurgitated and re-chewed. The food passes through three additional stomachs before entering the intestine. In spring, the deer prefer new plant growth and herbaceous plants. They feast on acorns, berries, fungi, grasses, lichen, nuts, shrubs and woody growth from summer through winter.
Black-tailed deer mate from November through December. Sparring to establish dominance is common among bucks. Does prefer bucks with large, heavy antlers. Fawns arrive in May or early June, weighing 6 to 8 pounds. Twin births are common, but a young doe may give birth to a single fawn. Bucks don't participate in raising the fawns, instead forming bachelor groups for the summer. Does and their fawns form small family groups, led by the oldest mother. Males fawns leave the family group when they reach maturity, at about 18 months old. Females are sexually mature at 2 years old.
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