Pronghorns: The Not-Antelopes of North America

 These mammals are often referred to as antelopes, but they aren't antelopes. They're also called speed goats, but they're not goats either. They're deer-sized, but they aren't deer. They have horns like an antelope, but they shed these horns annually like a deer. So what the heck is a pronghorn? Currently, they're considered most closely related to giraffes. They're even-toed ungulates. Pronghorns are known as the second fastest terrestrial animals alive today, but there's a lot more to them than speed. Do you even know why these not-antelopes are so fast?

Prior to the colonization of North America, there are believed to have been more than 35 million pronghorns spreading across the Plains and prairies of the central United States. Today, they're considered threatened, but with stable populations at about 500,000 individuals. They live in grasslands as well as sagebrush lands in Western North America. Many of these habitats have been disturbed or changed for human use, so the pronghorns live in fragmented patches across their former range. Pronghorns can't handle deep snow, so they migrate from northern areas to southern areas during the winter to avoid this. While they're deer-sized and deer-shaped, they don't have the same kind of leaping skills seen in deer. Snow is a problem because they can't bound through it the way a deer can. Fences are another issue. Due to their lack of leaping skills, pronghorns cannot effectively jump over fences. So, if a predator corners them along a ranch fence, their speed isn't enough to save them. These long-spanning fences that often denote land boundaries weren't present until after the colonization of North America. Although adult pronghorns can outrun any potential living predator, fences stop them dead in their tracks.

Pronghorn predators include coyotes, bobcats, wolves, bears, and golden eagles, with their babies being their main targets. Pronghorns have huge eyes that can see upwards of four miles to scan for predators, and they run faster than anything that might be chasing them. Because they evolved alongside even faster animals, such as cheetahs and hyenas, they had to be fast to outrun these ancient predators, so they're on par with the fastest land animals still alive today.

The name "pronghorn" comes from males who have just that—pronged horns. Females can sport horns as well, but they don't always, and the horns in females aren't pronged. Males have larger, longer horns than their female counterparts. The horns are bone wrapped in a hard keratinous sheath that's similar to hair. These are shed and regrown each year. Male pronghorns are larger than females, but on average, these mammals stand about three feet tall at the shoulders and weigh from 90 to over 120 pounds. Pronghorns are sometimes referred to as "dainty eaters." They move around a lot as they eat and only pick out the best-looking morsels, such as new growth on plants. They're herbivores and eat shrubs, flowering plants, lichens, and sometimes grasses, though these aren't a favorite meal. Yes, even though they live in vast grassland habitats, they prefer not to eat grass.

These not-antelopes form large herds in fall and winter, which also correlates to their breeding times in spring and summer. They disperse into smaller family groups of females and their young, bachelors, and solitary older males. Their babies are born in May to June, and a majority of the time, they have twins. Baby pronghorns can run faster than a human within their first week of life, and they take about four to five months to wean. The female sexually matures as early as five months, right after they finish weaning, but it may be upwards of 11 more months before they actually reproduce. Males are also ready to start families at about a year old, but they're often restricted by older males. Male pronghorns lock horns in dominance matches. These control blood, but they're rarely fatal.

In the wild, pronghorns live to be 7 to 10 years old.