The Return of the Bison to Mexico’s Chihuahua Desert

A species lost for over a century is once again shaping northern Mexico’s landscape.

The American bison, a species that once roamed across vast stretches of northern Mexico, has been reintroduced to parts of its historical range after being hunted to near extinction in the late 19th century. 

What began as a single conservation herd in Chihuahua has grown into a multi-state recovery effort that is now showing measurable ecological results.

The Extinction of the Bison in Mexico

The American bison historically ranged across northern Mexico, including Chihuahua, Coahuila, Sonora, Nuevo León, and Durango. By the second half of the 19th century, however, the species had been nearly eliminated south of the U.S. border.

Many factors drove the decline. Commercial hunting for hides became a massive industry, while sport hunting left animals killed and abandoned. A decisive factor was the explicit policy of the United States government in the 19th century, which promoted the slaughter of bison to eliminate the primary food source and livelihood of Native American peoples, weakening them forcibly. 

Railway companies also hunted bison to feed workers and to prevent herds from blocking tracks. By 1900, only a little more than 500 individuals remained across North America. In Mexico, the last wild bison disappeared from the landscape around 160 years ago.

The Janos Model: From 23 to Nearly 500

The modern recovery program began in 2009, when 23 American bison from Wind Cave National Park in South Dakota were transferred to Rancho El Uno in the Janos Valley of Chihuahua. The animals were selected partly because genetic research found the Wind Cave herd to have high genetic diversity and no evidence of domestic cattle gene introgression.

Rancho El Uno is an 18,546-hectare conservation property within the Janos Biosphere Reserve, which itself protects approximately 13 million acres. Janos preserves some of the last large natural grasslands in northern Mexico and was chosen because it had a small wild bison population in the early 1990s.

The founding herd of 23 animals grew steadily. By 2017, the Comisión Nacional de Áreas Naturales Protegidas reported 123 bison in Janos. A year later, the herd numbered around 230. By the end of 2025, the population in Janos and Rancho El Uno had reached between 460 and 500 individuals.

Expansion to Coahuila and Sonora

The success in Janos allowed the model to be replicated elsewhere. In 2020, 19 bison were transferred to Coahuila to establish a second conservation population in the Maderas del Carmen and Ocampo protection areas.

In August 2025, three more bison arrived at the El Santuario Ecological Reserve in Cuatro Ciénegas, Coahuila, a project led by the Fundación Pro Cuatrociénegas. This initial group came from the Museo del Desierto in Saltillo.

On November 26, 2025, an additional 44 bison arrived at El Santuario after a journey of more than 700 kilometers from Rancho El Uno in Janos. The group consisted of 38 females and 6 males.

The El Santuario reserve spans over 1000 acres and is located about 10 kilometers from the town of Cuatro Ciénegas. The site was chosen because it is naturally surrounded by mountains, requiring less than 100 meters of fencing to keep the animals within the conservation area.

In February 2026, another 29 bison were transferred from Janos to Sonora, establishing a new herd in the Cuenca Los Ojos region. The group included 10 males and 19 females. Within months, 10 calves were born, demonstrating rapid reproductive success.

Ecological Impact: The Bison as Ecosystem Engineer

The reintroduction is not merely about increasing bison numbers. The goal is to restore the ecological role of a large grazer that had shaped North American grasslands for millennia.

Bison affect their environment through several mechanisms. Their grazing creates differences in vegetation height and density. Their hooves disturb the soil, improving water infiltration. Their dung and urine redistribute nutrients, and their movement can transport seeds. One of their most distinctive behaviors is wallowing, where they roll repeatedly on the ground to create shallow depressions. 

Researchers at Janos examined these wallows after the 2009 reintroduction and found differences in plant composition and structure. Some plant species were found only within wallows while others occurred only outside them, suggesting that bison activity creates small patches with different ecological conditions.

A Cultural and Spiritual Dimension

For the N’de people, better known as the Apache, the return of the bison carries significance beyond ecology. The bison, known in their language as Iyané, is a central element of their cosmology and identity.

Juan Luis Longoria Granados, leader of the Nación N’de and director of culture for the Pro Cuatrociénegas Foundation, led a traditional welcome ceremony when the 44 bison arrived in Coahuila. “The return of the bison is not only an ecological achievement; it reconnects the N’de Nation with a brother that is part of our identity, spirituality, and collective memory,” he said.

The ceremony offered grass and feathers to entrust the herd to creative forces, with a central request that the territory recover its balance.