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The Mule-Deer



Odocoileus hemionus


Range


Throughout the entire western United States, including the four deserts of the American Southwest.

Habitat


Mule Deer moves between various zones from the forest edges at higher elevations to the desert floor, depending on the season.

Description

Mule Deer have large ears that move constantly and independently, from whence they get their name, "Mule" or "Burro Deer." They do not run as other deer, but have a peculiar and distinctive bounding leap (stotting) over distances up to 8 yards, with all 4 feet coming down together. In this fashion, they can reach a speed of 35 mph for short periods.

This stocky deer with sturdy legs is 4 to 6-1/2 feet in length and 3 to 3-1/2 feet high at the shoulder. During the summer, the coat on its upper body is yellow- or reddish-brown, while in winter more gray. The throat patch, rump patch, inside ears and inside legs are white with lower portions running cream to tan.

The Mule Deer is slower and less colorful than the White-tailed Deer, but its pastel, gray-buff color provides a physical adaptation to the desert environment which disguises it from predators like the Cougar, the Coyote and the eagle who will swoop down on a fawn.

Another physical adaptation, its larger feet, allows the Mule Deer to claw out waterless as much as two feet deep, which it detects with its keen sense of smell.

Males are larger than females. The bucks' antlers, which start growth in spring and are shed around December each year, are high and branch forward, forking equally into 2 tines with a spread up to 4 feet.

Mule Deer have no canine teeth and, like the cow, have a multi-part stomach, the first two chambers of which act as temporary storage bins. Food stored here can be digested later when the deer chews its cud.

There are 2 major subspecies: the Mule Deer, with tail white above, tipped with black; and the Black-tailed Deer, with tail black or brown above.

Habits

Mule Deer are active primarily in mornings, evenings and moonlit nights. This inactivity during the heat of the day is a behavioral adaptation to the desert environment that conserves water and keeps the body temperature within livable limits. Sweat glands and panting also provide evaporative cooling during hot periods.

Mule deer are browsers and eat a great variety of vegetable matter, including fresh green leaves, twigs, lower branches of trees, and various grasses. They are particularly fond of blackberry and raspberry vines, grapes, mistletoe, mushrooms and ferns. They eat so carefully they can even consume the fruit of cactus.

The mating season for Mule Deer reaches its peak in November, as antlered stags round up females and fight for their possession. In December, antlers are shed. Males and females mix freely while traveling together in groups during winter months, often down to the desert floor.

When antlers start growing again in the spring, the group breaks up. The females go off by themselves and eventually give birth and nurse their young; the males wander in friendly twosomes or small bands throughout the summer months as antlers grow.

From April through June, after about a 200-day gestation period, the doe delivers 1 to 4 young (normally 2). The fawn, colored reddish with white spots, weighs about 6 pounds at birth. It must nurse within the first hour and stand within the first 12 hours. During early weeks of life, the fawn sees its mother only at mealtimes for feeding. Spots begin to fade by the end of the first month.