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Pronghorn: Survivors of the Ages

a small brown animal standing on grass looking toward the camera

In the heart of Yellowstone National Park’s Northern Range, a dense population of hoofed animals thrives, basking in the bounty of vegetative diversity. Among the eight ungulate species found in the park—mountain goat, elk, mule and white-tailed deer, moose, bison, bighorn sheep, and pronghorn—the pronghorn emerges as a superstar of evolution, adaptation, and endurance. 

an animal looking at the cameraPhoto courtesy of Evan Watts @ Watts Wildlife Photography

Camouflaged in the park’s Lamar Valley and Little America’s open sagebrush, the presence of pronghorn today offers a glimpse into an ancient world. An untamed swath of wilderness teeming with wooly mammoths, dire wolves, saber-toothed cats, and countless others roaming a landscape littered with inland seas, spewing volcanoes, and the coming and going of ice ages. 

a close up of an animalPhoto courtesy of Rob Harwood @ Rob Wild Photography

Pronghorn (Antilocapra americana) are a roughly 20 million-year-old relic of this North American wilderness, having evolved alongside ice-age mammals now long extinct. One of these animals was the North American cheetah. This cat, Miracinonyx trumani—a top predator worthy of comparison to the famed dire-wolf—was capable of short-distance sprints up to 60-65 mph. Against speeds like that, the pronghorn proved to be a master of evolution–adopting similar sprinting speeds while adding the endurance needed to outlast the short-distance racing capabilities of its pursuer. With an oversized windpipe and large heart, the pronghorn can sustain speeds of up to 55 mph for a half mile and 32-45 mph for up to four miles–making it the fastest land mammal in North America. The pronghorn’s speed continues to serve it well in this modern Yellowstone landscape where wolves, mountain lions, and other predators roam—and hunt— alongside it. 

a group of sheep that are standing in the snowPhoto courtesy of Rob Harwood @ Rob Wild Photography

Among modern-day horned animals, pronghorn have a genetic trait that sets them apart in the long-term game of species survival. Horn size and symmetry matter to all horned animals—communicating good health and strong genes (a desirable attribute for receptive females searching for ideal breeding partners). When a pronghorn buck’s horn is damaged one year – it will be replaced with a new one the next. This adaptation allows males to replace broken horns every year with an aesthetically “superior” rack – increasing its odds of successfully breeding in subsequent years. This extraordinary evolutionary advantage–shedding and regrowing horns every year– gives pronghorn an edge over their larger horned counterparts whose horns are, with few exceptions, permanent. Sadly for bison bulls, billy goats, and bighorn rams, a severely damaged horn could end its genetic line. 

Photo courtesy of Rob Harwood @ Rob Wild Photography

Despite the tumultuous climatic, geologic, and human-caused changes over the millennia, pronghorn remain well-suited to the modern-day glacially carved valleys of Yellowstone and surrounding areas. As opportunistic herbivores, their varied diet includes lichens, grasses, small forbs, and, in winter, large amounts of sagebrush. Sagebrush–while tolerated in small quantities by many species–has toxins that cause digestive discomfort in nearly all of Yellowstone’s hoofed animals when consumed in large quantities. Pronghorn, however, are equipped with proportionally large livers, which may allow them to process the plant toxins found in sagebrush and other vegetation that comprise most of their winter diet. Combined with their remarkable ability to migrate hundreds of miles each year in search of easier browse and manageable snow depth (they’re only three to five feet tall!), pronghorn have proven to be remarkably well-adapted to life in the wilds of the Greater Yellowstone Ecosystem year-round. 

a group of brown horses standing on top of a dry grass fieldPhoto courtesy of Evan Watts @ Watts Wildlife Photography

As the pronghorn graze quietly in the valleys and foothills of the world’s first National Park, they invite us to imagine an unfamiliar landscape where the predatory and dietary challenges faced are vastly different today. And yet, here they stand before us. Their continued existence in Yellowstone inspires observers to consider what wild once was and offers future decision-makers insights into what wild could be. The privilege of sharing the landscape with these masters of survival, evolution, and adaptation is an opportunity, an honor, and a testament to the resilience and adaptability of wildlife in the face of change – a story that continues to captivate and challenge modern humans to this day.

Blog written by Yellowstone Wild General Manager, Tyrene R. and Lead Naturalist Guide, Laura L.

Summer 2024 Yellowstone Wild Naturalist Guides

To learn more about Laura, Tyrene, and the entire Yellowstone Wild Team, visit our “About Us” page

From $4500

We’re excited to be offering two immersive Yellowstone Photography Workshops for Winter 2025. Each workshop will focus on encouraging all levels of photographers to hone their visual storytelling skills through one-on-one instruction with a local professional photographer.

2025 Workshop Dates and Instructor

Workshop 1:   9-Days: 1/5/2025 – 1/13/2025 ~ Led by local photographer Evan Watts 

Workshop 2:   7-Days: 2/9/2025 – 2/15/2025 – Led by local photographer Rob Harwood