Pronghorn
North America's fastest land mammal, seen in the grasslands at the north end of Lava Beds, built to outrun a predator that went extinct 12,000 years ago.
Pronghorn at a glance
Antilocapra americana PRONG-horn; Antilocapra americana is an-TIL-oh-KAP-ruh uh-MER-ih-KAH-nuh
- Type
- Mammal · ungulate
- Diet
- Herbivore
- Size
- Stands about as tall at the shoulder as a kitchen counter (35 to 40 inches), and a big male weighs about as much as two large dogs combined (100 to 125 pounds / 45 to 57 kg); females are somewhat smaller (90 to 110 pounds / 41 to 50 kg).
- Lifespan
- Around 7 to 10 years in the wild.
- Conservation
- Least concern
Eats sagebrush, rabbitbrush, forbs, some grasses
A pronghorn browses sagebrush and other shrubs most of the year, switching to soft grasses and wildflowers when they're available in spring. Its liver is large enough to help break down plant toxins that would sicken other grazing animals.
Should you worry?
Not a real worry: pronghorn keep their distance from people on their own. The actual risk runs the other way, a fast-moving car meeting a pronghorn crossing a road. Slow down through open grassland, never approach a fawn lying alone in the grass (its mother is almost always nearby, just out of sight), and never try to feed or pet one.
North America’s fastest land mammal would rather crawl than jump. At the north end of Lava Beds, a small group of pronghorn reaches a rancher’s fence, and instead of clearing the top wire in a single bound, they drop low, one at a time, and half-crawl under the bottom strand. A pronghorn can hold close to 55 miles an hour for half a mile and keep near 45 mph far longer than that, so watching one hesitate at a plain wire fence looks, for a moment, like watching the fastest kid on the playground stop to ask permission at a puddle.
The habit makes sense once you know what the speed was built for. Biologists think pronghorn evolved that engine to outrun the American cheetah, a lion-sized sprinting predator that hunted the same grasslands until it went extinct around 12,000 years ago. Nothing alive today, not a wolf, not a mountain lion, can run down a healthy adult pronghorn in open country. What pronghorn never evolved, because they never needed it, was a reason to jump. A barrier you can outrun doesn’t need clearing. A barrier that just sits there, wire strung tight at exactly leg height, is a problem speed alone can’t solve.
It’s fences, not predators, that pronghorn herds struggle with today, and it shows in how they move along a boundary line: pacing, testing the wire, looking for a gap low enough to slip under before trying anywhere else. Some ranchers near pronghorn range now leave the bottom wire loose or swap it for smooth wire without barbs, a small adjustment for an animal that solved every problem chasing it across the Ice Age except the one that doesn’t move.
Did you know?
- A pronghorn can hold about 55 miles an hour for half a mile and close to 45 mph over much longer distances, the fastest sustained speed of any land animal in the Western Hemisphere.
- Scientists believe pronghorn evolved that speed to escape the American cheetah, an ambush predator that vanished from North America around 12,000 years ago, which is why nothing alive today can actually catch a healthy adult.
- Even though it can run that fast, a pronghorn doesn't like to jump. Faced with a fence, it will try to crawl underneath the bottom wire rather than leap over the top.
Common questions
Is a pronghorn an antelope?
People often call it the American antelope, but it isn't a true antelope at all. It's the only living member of its own family, more closely related to giraffes than to any African or Asian antelope.
How fast can a pronghorn run?
About 55 miles an hour for half a mile, and close to 45 mph for much longer stretches, faster than any other land animal in North or South America.
Can pronghorn jump fences?
They can, but usually won't. Faced with a fence, a pronghorn will try to crawl underneath the bottom wire instead of leaping over, even though it's fast enough to outrun almost anything.
Are pronghorn dangerous to kids?
No. They avoid people and keep their distance on their own. The real danger runs the other way: cars hitting pronghorn crossing a road, so drivers should slow down through open grassland.