Sonoran Pronghorn

Antilocapra americana sonoriensis
A geographically and genetically distinct sub-species of pronghorn, the Sonoran pronghorn is smaller and lighter in color and is adapted for survival in desert conditions. The males weigh up to 130 lbs. and females up to 110 lbs. Pronghorn are slightly smaller than a white-tailed deer with a shoulder-height of about three feet.

Both male and female have white bands across the front of their neck with a 2-4 inch black mane that goes down the back of their neck. The upper part of their body is light brown and their underside and rump are white. The males have a black mask and cheek patches. Both have extra-long white hair on their hind section that stands up when they are frightened. This can be seen from a distance and serves as a visual locator – the bold, white markings help pronghorn find each other from long distances on the large, open range. It can also be used as an alarm to let other pronghorn know that danger is nearby. Pronghorn can reach speeds of up to 60 miles per hour on short distances and can maintain a speed of 35 mph for longer distances.

While both sexes have horns, the females’ are short and look more like a bump. The males’ are black and about 10-12 inches long. Their horns extend up and point backward with a small tine (prong) that points forward. The unique design of their horn is what earned the species their name – pronghorn.

Pronghorn’s eyes are high on their head and they can spot movement several miles away. They are known for being extremely shy and are easily spooked. Their wariness, along with their good eyesight and speed, is very important to their survival. They are also well adapted to the desert conditions and during extreme heat are able to raise patches of their stiff hair to release heat. These same hollow hairs serve as insulation during the winter.

The pronghorn does can breed at 16 months; the bucks are able at one year of age. They have a 245 day gestation period. Pronghorn can have twins when food is abundant but most deliver one fawn that weighs between five and seven pounds. When their fawns are still very young, they remain well hidden while the doe is away foraging. Upon her return, the fawns will emerge to feed. The fawns do not emit a smell so it is hard for predators to find them. Though typically able to stand a day after being born, they will lie very still throughout the day waiting for their mother to come back and feed them, which is typically twice a day. At about six months of age, the young pronghorn will be independent of its mother.

The Sonoran pronghorn has a digestive system similar to cows. They have a four-part stomach that allows them to digest the succulent desert vegetation that makes up most of their diet. As desert vegetation dries with the onset of summer, water availability becomes increasingly important for digestive purposes and pronghorn rely on chainfruit cholla fruits as a source of moisture when water is otherwise unavailable.

Pronghorn were once as widely distributed as buffalo. The desert ranging pronghorn, including the Sonoran pronghorn, ranged widely but in reduced numbers within the Sonoran desert in Arizona and California down into Sonora, Mexico – a broad, open desert landscape with limited vegetation. Today they are reduced to an estimated 160 free ranging animals within the United States, and an additional 240 free ranging within Sonora Mexico.

Facts About Sonoran Pronghorn

Speed: Can reach speeds of up to 60 mph

Eyesight: Sense movement and can even distinguish objects several miles away

Behavior: Easily spooked by cars, aircraft and people and will try to avoid

Lifespan: 10-12 years in the wild