Bison came back after 200 years, and the desert did too

Bison are back in Mexico's Chihuahua Desert after roughly 200 years, following a series of reintroductions led by the Fundación Pro Cuatrociénegas. Last year, 48 of the animals were moved from other parts of Mexico into El Santuario Wildlife Reserve, a core area of the federally protected Cuatrociénegas landscape in Coahuila. The 324 square mile reserve is known for deep pools, gypsum sand dunes and unlikely plant life in the surrounding aridity. Bison shaped these arid grasslands for millennia before disappearing. Weighing more than 1,000 pounds, they break up soil with their hooves and carry seeds in their wooly coats over long distances. Overpopulation is a concern now that the Mexican wolf, their old predator, is gone. "It offers you so much hope," said Gerardo Ruiz Smith, the foundation's director, "simply bringing back a fundamental species that was there before and should be there." A puma might still take a sick or young one. Mostly, the herd is left to roam.