Another
interesting mammal that spends most of its time on the prairie is
the pronghorn antelope. Pronghorns are true American natives, found
nowhere else in the world. they have roamed the plains and deserts
of North America for at least the last million years in substantially
the same form. One can truly call this animal unique: he is the lone
member of his family, Antilocapra americana, which literally
means the "American goat-antelope." The
pronghorn has exceptionally keen vision complemented by excellent
hearing and sense of smell.
Both sexes have
horns, but the female's are only tiny spikes and are rarely pronged
as are the twelve to eighteen-inch horns of the male. The horn is
made up of two parts: a bony core covered by a black outer sheath.
This sheath is made up of a stiff, hair-like substance. Pronghorns
are the only animals in the world who shed their horns annually.
The outer sheath of the horn falls off each fall and grows back
by the following summer.
The coloration of the pronghorn
varies from light tan to a rich brown with prominent white patches
under the stomach and on the rump. In times of danger, the hairs
of the rump can be held erect to produce, in the bright sunlight
of the plains, a white flash visible for many miles. Along the neck
there is a thick mane of dark brown to black hair. Pronghorn bucks
have black patches on the lower jaw below the eye and a black mask
extending back from the nose. These markings make it easier to distinguish
the male from the female. No other animal is more strikingly beautiful
than the pronghorn when he "poses" on the open plains.
The
running gait of the pronghorn is beautifully smooth and their powerful
legs can carry them at a remarkable pace across the roughest kind
of terrain. As the fastest North American mammal, pronghorns can
reach speeds of 60 miles per hour. At high speed they cover the
ground in great strides of 14 to 24 feet, and are known to run for
long distances at speeds of 30 to 40 miles per hour.
Fall signals
the beginning of the intensive mating season. The territorial bucks
are especially aggressive in defending their areas. Brief fights
develop between males and occasionally one is seriously injured.
Ambitious bucks may develop harems of 3 to 8 or more does.
The young are born in late May or early June
with about 60% of the births being twins. At birth, fawns weigh
5 to 6 pounds and lack the spots that are characteristic of deer
and elk fawns. The newborn do not have an odor and instinctively
lie motionless for hours. This is their main defense from predators
such as bobcats, eagles, and coyotes.
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