Species Spotlight – Pronghorn

Devlin Holloway

A long list of charismatic animals inhabits Oregon’s high desert. Species such as the Greater Sage-grouse, bighorn sheep, cougars, burrowing owls and even the occasional black bear or wandering moose (okay, just one moose), can all be found exploring the characteristic rimrock, sagebrush, and open spaces of the state’s eastern half. In fact, many hundreds of species of wildlife call this region home, representing a rich diversity of both grassland and shrub-steppe wildlife species.

Perhaps the most recognizable wild character of Oregon’s dry side is the pronghorn (Antilocapra americana).

The pronghorn is the fastest land animal in North America, able to reach speeds up to nearly 60 miles per hour. Sometimes referred to as the “Prairie Ghost,” the pronghorn’s speed is a relic from a bygone era when they were paired against the worthiest of carnivorous adversaries, the North American cheetah.

While they are commonly known as pronghorn antelope or even just antelope, pronghorn are not antelope. Instead, they are the last living species of a broad group of ungulates that once roamed North America, antilocaprids (think “antelope-goat”). Antilocaprids went all but extinct during the last ice age, leaving only the pronghorn as evidence of their widespread influence on the grassland ecosystems of North America.

Pronghorn are still well adapted to the extreme temperatures and low shrub communities characteristic of much southeastern Oregon. Unlike other North American wild ungulates (hoofed mammals), pronghorn do not rely on tall vegetation for hiding cover, preferring rolling topographies with a mix of grass and shrub species. Having evolved the largest eye relative to their size of any North American ungulate, the pronghorn instead relies on both its eyesight and speed to evade predators.

Both male and female pronghorn are fit with horns that extend from the top of their head. Unlike their horned counterparts (e.g. goats) pronghorn actually shed the sheath of their horns each year. While both male and female possess horns, only the males have a forked horn, or prong, that gives the animal its name.

Similar to sage-grouse and pygmy rabbit, pronghorn are considered a sagebrush obligate species, meaning they depend on intact sagebrush steppe ecosystems to survive. The species’ original range was larger than that of the American bison, and their population once numbered in the staggering tens of millions. However, in the span of just a few generations, pronghorn populations crashed, heavily impacted by habitat degradation, over hunting and disease. By the late 1800s, there were estimated to be a mere 20,000 left in North America. Concerns about their fate led to conservation efforts to protect the species and their habitat. In the northern Great Basin, these efforts resulted in the establishment of Hart Mountain National Antelope Refuge and Sheldon National Wildlife Refuge in the 1930s.

Today, the Greater Hart-Sheldon Region is one of the best places in the arid west to see pronghorn in their native habitat. Recent surveys by state and federal biologists documented over 7,000 individuals in the Hart-Sheldon population, equal to roughly half of the observed individuals in the state.

In an effort to better understand where and when pronghorn migrate within the Hart-Sheldon Region, the U.S. Fish and Wildlife Service placed GPS collars on over thirty female pronghorn in 2011. The service found that the location and timing of migration movements can vary widely from year to year, and further documented the critical importance of habitats between the two refuges, on lands managed by the Bureau of Land Management, in maintaining the connectivity of seasonal migration routes. One intrepid individual was documented moving roughly 100 miles between winter and summer ranges, a distance that is among the longest ever recorded for pronghorn.

If you’d like to see pronghorn, consider Hart Mountain in the late spring. In May and early June, after a 250-day pregnancy, female pronghorn give birth to precocial (hatched or born in an advanced state and able to feed itself almost immediately) twin fawns. Weighing up to 9 pounds each, pronghorn fawns are able to walk within a mere 30 minutes of being born. The nutritious spring growth and intact plant communities at Hart Mountain are some of the most important fawning grounds for pronghorn in the northern Great Basin – an excellent place to start a desert adventure.

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John Cunningham, ONDA member and volunteer

John Cunningham, ONDA member and volunteer

Restoration is hard slow work. It takes hold, or it doesn’t, in fits and starts. The immensity of the need can be discouraging, but we must carry on. I am so thankful ONDA carries on.

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Aaron Tani, Sage Society Member

Aaron Tani, Sage Society Member

“It feels good to support ONDA on a monthly basis, because I know they never stop supporting our public lands. ONDA works to help make our lands a better place for the future, and I feel like I’m a part of that every month with my support.”