Little over a decade ago, the peninsular pronghorn (Antilocapra americana peninsularis) seemed to be nearing extinction in the wild. But today the pronghorn subspecies is on track to repopulate its fog-desert habitat on the Baja California Peninsula, thanks largely to hands-on conservation efforts by Mexican biologists. Since shrinking to the point that a 2010 census detected no peninsular pronghorns, the animal’s wild population is on the rise—recently surpassing 300.

“We have seen a sharp turnaround in numbers thanks to a successful reproduction program that puts the peninsular pronghorn population in a much more stable position,” says Lizardo Cruz, coordinator of species at risk in Mexico for the international environmental organization WWF.

Pronghorns, the only living species of the antilocapridae family of cloven-hoofed mammals, have evolved in North America over 20 million years. They can run at speeds approaching 60 miles per hour, making them the world’s second-fastest mammal behind the cheetah, and they perform crucial environmental services as an umbrella species in their natural habitat.

In all, there are five subspecies of Antilocapra, with the peninsular pronghorn—the one endemic to Baja California—considered to be at the greatest risk of extinction. In 2021 the International Union for Conservation of Nature (IUCN) listed the peninsular pronghorn as endangered, though with a growing population. The IUCN does not normally distinguish among subspecies in its threatened-species listing, but it bowed to pressure from Mexican conservationists.

One other pronghorn subspecies is listed as endangered by the Mexican government—Antilocapra americana sonoriensis, or the Sonoran pronghorn, which lives in Mexico’s northern state of Sonora.

Among the healthier pronghorn subspecies populations is the Antilocapra americana mexicana, or Mexican pronghorn, which can still be found in the northern Mexican states of Chihuahua, Coahuila, and Durango, as well as in the United States. Indeed, because U.S. populations of that subspecies and two others—Antilocapra americana americana and Antilocapra americana oregona—collectively number near one million, the IUCN classifies the pronghorn species’ overall as of “least concern.”

The pronghorn once roamed throughout southern Canada and the great plains of the United States west of the Mississippi River. In Mexico the species was found in current-day Sonora state, the Baja California Peninsula, and the high plateau of Central Mexico, extending as far south as the Valley of Tehuacán in what is now Puebla state. It is calculated that in the United States alone there were 40 million pronghorns until the mid-1800s, but indiscriminate hunting and human-driven land-use change decimated the population, reducing it to 25,000 by the turn of the century. A massive conservation effort carried out in the United States during the 20th century, however, helped build the pronghorn population back to a recent range of 800,000 to 1.1 million.

The three subspecies of pronghorn living in the United States have become the focus of a lucrative hunting industry that generates fee and tax revenues that help support state-government programs aimed at ensuring conservation of the animal. Mexican experts say they hope a similar species-conservation model can be adopted for the Peninsular pronghorn. But for now, they say, the animal’s numbers in the wild remain too low.

Among those leading the recovery effort is biologist Víctor Sánchez, whose interest in the topic dates from his days as an undergraduate at the National Autonomous University of Mexico (UNAM), where he wrote a thesis on pronghorn reintroduction in 1972. Sánchez has headed the peninsular pronghorn conservation program at Mexico’s National Commission of Natural Protected Areas (Conanp) since 1998. He says land and aerial counts indicate there are currently 300 of the animals in the wild, with approximately 20 additional offspring born recently.

A further 350 are living in captivity, of which 50 are in zoos in the United States. Sánchez says building a captive population at a geographical remove provides crucial insurance: If illness depletes wild pronghorn herds, captive animals can be used to underpin an emergency repopulation effort.

The fact that wild peninsular pronghorn numbers now surpass 300 comes in large part thanks to Sánchez, who has headed two Conanp-managed protected areas on the Baja California Peninsula and promoted the animal’s conservation in both.

Since 2003, he has served as director of the Valle de los Cirios natural area in the southern portion of Baja California’s municipality of Ensenada. For the eight years before moving to Valle de los Cirios, he was director of the El Vizcaíno Biosphere Reserve in the state of Baja California Sur. The contiguous protected areas are home both to captive-bred and wild peninsular pronghorn populations.

“Throughout my time as director of protected areas, I have always sought to implement policies that will support the conservation of the pronghorn—but, just as importantly, its natural habitat,” Sánchez says. “Otherwise, there can be no conservation.”

From 1998 to 2006, Sánchez and his team captured a total of 17 young and 30 adult wild peninsular pronghorns in the Vizcaíno reserve to start the current reintroduction program, which is seen as instrumental in the animal’s turnaround. The program initially employed a nursing technique Sánchez developed for pronghorns in 1984 while working at the General Directorate of Wildlife Fauna, a federal wildlife-conservation agency.

“We would wait 24 hours after the pronghorn was born so that it received colostrum from its mother to strengthen the immune system,” Sánchez says. “Then we would remove the young, hydrate them with water and slowly introduce Carnation [evaporated] milk. We would feed them every four hours for four months—a very labor-intensive, rigorous process that involved sterilizing bottles and all the care and attention that a baby would require.”

Now the young are separated from their mother at birth and fed bovine colostrum and bovine milk for the duration of their lactation period. This updated method has been shared with other institutions in Mexico and the United States, such as the University of Arizona, to aid conservation of other pronghorn subspecies. It is costly, requiring a veterinarian and four assistants to raise 10 young pronghorns.

Because the peninsular pronghorn population has grown larger, however, young animals are being raised by their mothers, both in captivity and in the wild. The improved feeding method is now only used in special cases, such as when young captive pronghorns are slated for transfer to a zoo.

Female pronghorns reach sexual maturity at 18 months and typically have one offspring the first year and an average of two annually during the rest of their nine-year average lifespan. “The young, which are born between January and March, have a 30% to 40% rate of survival rate in the wild, which is very low because the lack of food in the wild means there is a high rate of abandonment,” says Sánchez. To improve their chances, his team provides alfalfa and water at a total of five feeding stations in the Vizcaíno and the Valle de los Cirios reserves.

“In the current wild peninsular pronghorn population in Baja California, between 60 and 70 young pronghorns survive each year,” Sánchez says. “Our aim is for 100 to survive each year so the biomass increases as much as possible and the population can stabilize naturally, only fluctuating according to rain cycles and availability of habitat.”

Sánchez forecasts that at the current rate of growth, the pronghorn population will take 15 years to grow big enough to be considered stable. That assumes the animal’s current threats do not grow excessively dire. Coyotes constitute one of the most serious such threats. Adult pronghorns can escape coyotes, given their extraordinary speed. But Baja’s peninsular pronghorns are outnumbered by a large coyote population, making it challenging for them to defend their young.

Drought poses another threat. From 1997 to 2010, rainfall totaled just 200 millimeters (eight inches) in peninsular pronghorn habitat, which receives most of its moisture from mist that wafts east from the Pacific Ocean and west from the Sea of Cortez. In times of drought, the pronghorns can survive by licking the morning dew and absorbing humidity from the air. But amid a severe lack of water, they can’t digest the vegetation they eat—typically grasses, forbs, sagebrush, and other prairie plants.

Yet another challenge is competition with cattle. Pronghorns graze selectively on shoots and other high-nutrition vegetation, so they only need to eat 250 to 300 grams per day. By contrast, a single cow can consume the same amount that 100 pronghorns eat daily, thus posing a potentially major threat to pronghorn food security.

Game hunting, which experts say could be harnessed to fund pronghorn conservation once the animal’s population is large enough, represents yet another threat—though not a pressing one at the moment. Says Sánchez: “Although hunting is not a major risk, a single hunter could set our conservation efforts back a long way in no time.”

In 1922, Mexico’s president at the time, Álvaro Obregón, banned hunting of peninsular pronghorn. Cruz, WWF Mexico’s coordinator for species at risk, says that the prohibition unfortunately lacked teeth.

“Had the prohibition been accompanied by complementary public policies and funds [to ensure enforcement], the peninsular pronghorn’s history would have been quite different,” he says.

According to Cruz, the peninsular pronghorn subspecies would likely be extinct now if it weren’t for the relentless work and dedication of experts such as Sánchez. “The reality is that the hunting ban was not adhered to,” he adds. “And there has been very little interest from society and the government in the peninsular pronghorn’s conservation.”

Cruz has worked as an advisor on pronghorn conservation programs since 2005. Prior to joining WWF in 2020, he served as Conanp’s director of priority species. He contrasts the conservation status of the peninsular pronghorn with that of the bighorn sheep, or borrego cimarrón (Ovis canadensis), a species that lives in Baja California and whose natural habitat stretches from Canada to Northern Mexico.

In 1998, the same year that Sánchez and his team started capturing young peninsular pronghorns for captive breeding, the Mexican government launched a market-based bighorn-sheep conservation strategy that involved selling licenses to hunt the animals at ranches with government-certified wildlife management plans. (See "Mexico’s wildlife strategy draws hunters... and heat " —EcoAméricas, November 1998.)

“By placing value on the bighorn, interest from landowners and society was created in the conservation of the species, and funds for their conservation are generated by the licenses,” Cruz says. “By contrast, the peninsular pronghorn has had next to no interest or funds and the conservation has required an extremely expensive and labor-intensive breeding and conservation effort in captivity.”

The still-small size of the peninsular pronghorn’s population is not the only reason that the animal has not yet become the focus of a hunting-based conservation strategy. Another reason is that it is classified as endangered, which under Mexican law precludes any hunting of the animal.

Experts look forward to the day when the peninsular pronghorn, its habitat, and local communities can benefit from funding that regulated hunting and related sports-hunting businesses could bring. Sánchez points to Mexico’s bighorn hunt.

Charging US$60,000 for each bighorn hunting permit, a single town in Baja California’s El Vizcaíno reserve has brought in more than US$7 million since 1997 in connection with the hunting of just five bighorns per year, he says.

Bighorns making large gains

Since bighorn hunters are only allowed to target older animals, hunts have had the effect of culling rather than indiscriminately depleting the bighorn’s population, which the Mexican government estimates at nearly 6,700 in Sonora and the Baja peninsula. That’s up from an estimated 2,500 in the period 2006 to 2012.

“Communities treasure and care for the bighorn and its habitat because they have seen the benefits of the income it provides,” he says. “The option of controlled hunting has made landowners prefer silviculture and the conservation of the bighorn’s habitat over destroying the habitat for cattle ranching.”

But for the peninsular pronghorn to reach that point, he adds, more time, work, and public education will be required.

“When a species is categorized as being in danger of extinction, it requires a lot of funding for conservation to take place without the species being touched,” Sánchez says. “For now, the peninsular pronghorn’s situation merits that status, but we need a big effort from society and government. We need the species to be socially and culturally valued so it can reach a lower-risk category and benefit from controlled, extractive management programs such as the one that benefits the bighorn.”

Sánchez says that if, as he expects, the peninsular pronghorn population becomes fully established over the next 15 years, the stage will be set for a “sustainable [hunting] scheme that generates economic resources and allows conservation of the habitat and its species, providing a resilient ecosystem that can help humanity.”

Indeed, the pronghorn is considered an umbrella species whose conservation benefits all species in Baja California’s fog desert. Known as the desert farmer, the animal breaks the saline surface of the land with its hooves and the excrement it leaves contains seeds of the plants it eats, contributing to the regeneration and distribution of desert vegetation. And given its preference for endemic plants, it promotes the regeneration of those species over invasive ones, which it often tramples.

Manifold benefits

The pronghorn’s urine and excrement, meanwhile, help fertilize the desert, and the animal’s habit of grazing small amounts from each plant before moving on has the effect of pruning native plants, thus stimulating their growth. The vegetation, in turn, provides humidity and refuge to other species and is key to ecosystem health and balance. Experts say populations of mice, rabbits, coyotes, eagles, and other local animals have increased as a direct result of peninsular pronghorn population growth.

“The peninsular pronghorn keeps the ecosystem healthy by creating and maintaining the necessary structures in the food chain,” says Cruz. “This allows the ecosystem to be more resilient. An increase in vegetation lowers the temperature and alters solar radiation. The presence of vegetation also prevents soil erosion when it rains. All of these factors lower the impact of climate change. So the well-being of the pronghorn communities is directly related to increased resilience of the ecosystem.”

For his part, Sánchez believes that success so far in the effort to conserve Baja’s peninsular pronghorns bodes well for the protection of pronghorns in other regions. “The peninsular pronghorn’s strength and ability to adapt to the extreme impact of climate change that we are experiencing in Baja California shows a huge potential for genetic and environmental resilience for the whole species,” he says.