Once counted in the millions across the North American plains, pronghorn dwindled to threateningly low numbers a century ago. Now, an effort by the Department of Game and Fish is helping to restore this icon of New Mexico’s grasslands.
Unique among North American ungulates, pronghorn can reach speeds required to outrun long-gone predators from the last Ice Age.
THE TRAP WAS SET BEFORE SUNRISE on a crisp, sunny morning in late February. From the helicopter where New Mexico pronghorn biologist Anthony Opatz watched, it resembled wings spread across the prairie, with wide lines drawn by fences in the dun-colored grass. The aim was to collect scattered groups of pronghorn, the reddish-brown-and-white horned ungulate native to New Mexico’s grasslands, in a circle of tarpaulin walls and metal fences. From there, they’d be loaded into trailers and transported across the state.
Getting to this moment had taken Opatz a year. He had negotiated with a private landowner who had a robust herd of pronghorn on his ranch, wrangled equipment and supplies, helped build a trap firm enough to hold a rushing herd, and assembled a team of roughly 60 New Mexico Game and Fish Department staff for a three-day job. He’d had to call it off once, when melting snow turned the ranch’s dirt roads to slippery mud. But a week later, with chase crews in trucks and more people hiding in freshly dug pits, Opatz climbed into the helicopter to catch the continent’s fastest land mammal.
A New Mexico Game and Fish Department staffer puts the trap’s metal fence in place.
The first European explorers to the plains of the American West, where pronghorn roam from Mexico to Canada, encountered herds that might have numbered as many as 35 million, nearly as abundant as the bison known for stalling westbound wagon trains for days. Pronghorn are an Ice Age holdover species, their thin bones and big nostrils built to sprint at twice the speed of any living predator on this continent. For millennia, they essentially had no challengers. Then, in the late 1800s, settlers moved in, began stringing up barbed-wire fences, which stop pronghorn in their tracks, and overgrazed grasslands with cattle and sheep.
Pronghorn populations plummeted. Biologists like Opatz have worked for decades to reverse that decline and return them to places from which they vanished. The current mission is twofold: restore a missing piece of the grassland ecosystem, and give biologists clues to what pronghorn most need from a landscape, so they can continue protecting the species into our wild and changeable future.
“I always thought it would be terrible to leave a world where I got to see a species and my kids or my grandkids weren’t able to, just because we’ve mismanaged them or did something where they weren’t able to persist,” Opatz says. “If we could just keep pronghorn going in New Mexico, that’s my main goal.”
The pronghorn move into the narrowing enclosure.
THE FIRST MORNING OF this winter’s trapping operation, the pilot swung wide around a small herd of pronghorn, dropped the helicopter toward the grass, and tried to steer the group into the funnel of fence. But the lead doe that directs traffic in the herd was smart, Opatz recounted later, shaking his head, smarter than he’d have believed they could be until he saw it.
Faced with the frightening prospects of a distant fence or a loud, whirling object overhead, she chose the danger in the sky, sprinting so close under the helicopter that her horns nearly hooked it. That group escaped. Then the wind picked up, grounding all flights. The day ended with an empty trap.
“They kind of know something is weird,” says Nicole Tatman, the big-game program manager for the Department of Game and Fish and a trap team leader. “We’ve created new fences they’ve not seen before, and they probably at some point smell people.”
Opatz and Rex Martensen, private land programs manager for Game and Fish, restructured the fences, trying again to fool the gaze of a sharp-sighted ungulate by hiding the straight lines in the landscape’s folds. The next morning, the helicopter swooped out over the scattered herds, but this time the chopper tried not to push as hard. For those watching in chase crews, the helicopter disappeared into a canyon, then rose over a ridgeline. As it did, dots of pronghorn appeared on the horizon as blocky silhouettes. The pilot hovered as the lead doe hesitated, then headed toward the trap. Dozens more followed. People jumped out of vehicles and from backhoe-dug pits to close the fences behind them. Then, a human wall of people walking shoulder-to-shoulder pressed the herd into narrower and narrower space.
A human wall pushes the herd forward.
“Almost every time, they’ll charge the line of people,” Tatman says. “It’s a little unnerving, having thundering hooves running at you.”
As their enclosure shrank, the herd balled up, showing either a line of faces or a row of white rumps, the white fur ringing their tails flipping up in their cross-prairie alert system. Once encircled in tarp walls 10 feet tall, a pulley snapped an even tighter gate shut.
The next steps were aimed to be executed quickly and efficiently, without overly stressing an animal that Game and Fish veterinarian Elin Crockett describes as “high-strung.” Checking body temperatures, bolting on GPS collars, and administering intravenous sedatives and anti-anxiety medications to help the animals endure the six-hour trailer ride to their new home required peeling individuals off the herd. Singled out in a dark enclosure, the roughly 100-pound animal was moved to a leather stretcher with leg holes cut through it. (Dangling with their feet suspended subdues the urge to sprint.) The work makes Opatz appreciate game wardens who are willing to step into a dark, confined space with a sharply horned and hoofed animal.
Game and Fish veterinarian Elin Crockett checks one of the pronghorn.
“It can get chaotic,” Opatz says. “The wardens are wonderful—they’re strongheaded, they love getting in there, and they like the scars that come out afterward.”
What a feeling, to wrap arms around a wild animal, its breathing and racing heart close at hand. But in some ways, it’s even better knowing where they’re headed and what they’re poised to do.
“Ultimately, intact ecosystems function better and are healthier than ecosystems that don’t have all their flora and fauna,” Tatman says. “And pronghorn are definitely part of this larger ecosystem.”
Sedatives, anti-anxiety meds, and a few brave game wardens help keep the animals calm.
PRONGHORN EVOLVED ABOUT 19 million years ago on a continent shared with American cheetahs, dire wolves, and saber-toothed cats. But about 9,000 years ago, a wave of extinctions swept through North America’s megafauna. Pronghorn retain a trait that was vital among now-lost predators: an ability to reach speeds of up to 70 miles per hour. At one week old, a fawn can outrun a human.
In a landscape where the fastest carnivores max out at 30 to 40 miles per hour, their pace amounts to ridiculous overreach—unless a pronghorn takes an interest in racing a car down the highway. This lone survivor remains from about 17 types of antilocaprids that once roamed North America, some smaller, and some with horns that spiraled or split like deer antlers.
“The pronghorn we see today are the lucky branch of Antilocapridae that have made it all the way here,” Opatz says. “There’s a case to make for pronghorn as the iconic mammal of North America, unique to here and a standout among other wildlife, estranged from its own family tree.”
Earliest accounts of the species confused them for antelope, a misconception that persists. Naturalists later set them in a family of their own—not just unique in species or genus, but the sole remainders of an entire family. Their closest living relatives are giraffes and okapi, and like some of those distant cousins of the African savanna, pronghorn also migrated to follow rainfall. Some herds in Wyoming still move 150 miles.
Biologist Anthony Opatz (right) spent a year coordinating the relocation efforts.
Fences put a stop to that. Pronghorn are physically capable of jumping fences—it’s a learned behavior elk and deer teach their calves—but generally, they don’t. They prefer to belly crawl or hip-slide under an unbarbed bottom wire about 18 inches above the ground. Opatz has seen them skid through at more than 20 miles per hour. A barbed-wire fence built to hold cattle can essentially become an impenetrable line. Coyotes, which could never have caught them in a straight run, have even learned to steer them up against fences and overtake them there.
Pronghorn may also have been overhunted, and they were certainly outgrazed. Rather than the grass that cattle favor, pronghorn browse on “basically anything that blooms,” Opatz says. But 1,400-pound cattle will eat those leafy green things, too, and will vastly outeat the 100-pound locals.
“With wildlife management, it’s often not one thing, it’s several things,” Martensen says. “In addition to water and plants, as [settlers] started into more cattle, more grazing, more fences, the pronghorn took a nosedive.”
At the population’s lowest point, in the early 1900s, the entire West was thought to hold only about 20,000, and New Mexico, a mere 1,700. The massive herds previously reported by new arrivals to the state in the mid-1800s had dwindled to scattered and fading clusters.
A helicopter herds the pronghorn into the waiting fences.
ONE OF THE PLACES PRONGHORN LIVED—and then didn’t—was the L Bar Ranch on the eastern flank of Mount Taylor. The property runs from high mesas, where elk, deer, black bears, and mountain lions roam among ponderosa pine forests, to grassy basins spiked with cinder cones. Once privately owned, the ranch’s 54,000 acres became a state wildlife area last year, making it prime real estate for the 77 pronghorn that were trapped this winter to rehome.
The dusty dirt road Opatz drove out toward the property wraps around a ridgeline with nothing visible beyond it but piñon and juniper woodlands, until the old ranch house, corrals, and an irrigated field come into view. Opatz, Martensen, and I headed out this spring to see if we could spot a few of the newcomers. As soon as Opatz parked alongside the other Game and Fish trucks at the barn and stepped out, one of the wardens called, “We saw your pronghorn.”
The warden had been there when the trailers pulled up to watch doors open and pronghorn spill out. “The bucks went to the left, and the does went to the right,” he recounts. “They kind of stared each other down, trying to figure out who’s in charge.”
Signals from their new GPS collars showed them spreading over the property. Some climbed to the plateau. Some headed toward the interstate.
Opatz keeps a close eye on their movements and will for years to come. When he noticed a group of signals lingering at one spot, he zoomed in on a satellite view and saw a fence between a herd and a water source. He sent staff to coil the barbed wire and wooden posts. The next day, the GPS dots moved to the water.
“This isn’t a great place for pronghorn at the moment, but it’s not terrible. As we continue to improve this, we’ll see how they respond to it, and that’ll help us in the future.”
—Rex Martensen, New Mexico Department of Game and Fish
Pronghorn lived at L Bar until as recently as 10 or 15 years ago, so it’s a place where they might be happy again, but only if biologists and wardens can figure out the problems they faced faster than those issues deplete this herd. The fences also must be spooled up before pronghorn imprint on those barricades. Their memory of what was once a wall often overrides their senses’ ability to recognize that the barrier has come down. Once, a herd wandered onto the runways at the Ratón Municipal Airport. They wouldn’t move out, even with massive gates propped open. Game and Fish staff had to net-gun them.
Remodeling the property for these new arrivals means pulling down miles of interior fences, as well as mending perimeter fences to keep cattle from trespassing and competing for limited leafy greens and water, the flow of which will also need bolstering. At some point, some of the piñon and juniper trees might be thinned to open more grassy areas where forbs grow, as well as views of approaching predators. But that’s an even harder project than the fences and the intruding cattle, so likely a longer-term one.
“This isn’t a great place for pronghorn at the moment, but it’s not terrible,” Martensen says. “As we continue to improve this, we’ll see how they respond to it, and that’ll help us in the future to better manage and augment other reintroduction programs. If we have a place that’s marginal, but not great, we’ll know right away these are the things we need to do.”
Thanks to relocation and other efforts, the pronghorn population in New Mexico is now estimated at 62,000.
Climate change also poses a pervasive challenge. More frequent and longer droughts are baking vegetation and drying out water sources. Increasingly severe weather also means more intense storms that flash arroyos with summer floods and pile winter snow so deep that pronghorn can’t paw through to eat the plants beneath. Fewer fawns are surviving already tough summer seasons.
But L Bar isn’t alone in the efforts to make New Mexico an easier place for pronghorn to thrive. Relocation efforts, which began in the 1930s with just six animals at a time and now aim for about 100 a year, have seeded other herds. The hope is to support pockets of resilient populations across the state. Landowners are also restringing wildlife-friendly fences to allow them to move more easily as rain and grass require.
Opatz, for his part, hopes L Bar’s herd is here for generations and available for people to connect with, including the nearby tribes that celebrate pronghorn in their ceremonies. A decade ago, New Mexico’s pronghorn population was near 40,000. It’s now estimated at 62,000.
Although the new L Bar residents stayed hidden despite our loops through the ranch, once again, travelers through the eastern plains are catching sight of them. “They’re so cool and they’re so easy to see—you don’t have to hike six miles into brush country to see a pronghorn,” Opatz says. “You drive down I-25 and they’re on the fence line.”
