08/25/2026
When the drought of 2000 emptied Big Bend National Park of almost every black bear that had spent a decade recolonizing it, a radio-collared female named Elektra crossed the Chihuahuan Desert into Mexico and survived. She returned to the park the following spring. Two years later, Dave Onorato found her in a den in the Sierra Quemada with two yearling cubs. The year after that, she had three more. The bear that walked into the desert during the worst food failure in the park's history came back and rebuilt.
Big Bend's bear population was a comeback story before the drought ruined it. Black bears had been extirpated from the park before its establishment in 1944. Ranchers, sport hunters, and predator control agents killed every one. For 40 years, the Chisos Mountains held no bears. Then in the late 1980s, a female crossed the Rio Grande from the Sierra del Carmen in northern Mexico, climbed through miles of open desert, and reached the forested slopes of the Chisos. Others followed. By March 2000, Onorato's research team was tracking 15 radio-collared bears in a population of 29, including six breeding-age females. The recolonization that nobody had assisted was working.
Then the acorns failed. The berry crop failed. The sotol and prickly pear produced almost nothing. The Chihuahuan Desert was already dry. In 2000, it became empty. A black bear preparing for winter denning needs to eat 15,000 to 20,000 calories a day during the fall hyperphagia. Big Bend offered almost none. The bears started leaving.
In September, Onorato's team could not locate several of their collared bears in the Chisos. They requested aerial flights outside the park. The signals came back from Mexico. Bear after bear had descended from the mountains, crossed the open desert, swum the Rio Grande, and headed south toward mountain ranges in Coahuila and Chihuahua where the mast crops had not failed as completely. They faced everything the desert held between them and the next patch of food: heat, dehydration, roads, fences, ranchers, and miles of terrain with no cover and no water. Several did not survive the crossing.
The population crashed from 29 to as few as five to seven animals. Only two adult females remained in the park. Twelve years of natural recolonization nearly erased in a single autumn.
Elektra was one of the bears that left. Her collar signal disappeared from the Chisos in the fall of 2000 and reappeared in Mexico. She survived the desert crossing that killed others. In the spring of 2001, her signal came back into the park. She had walked home.
By 2003, Onorato was ready to check on her. He and a team hiked into the Sierra Quemada, a rugged subrange in the southern part of the park, tracking her collar frequency through the canyons. The trip felt like an extended scavenger hunt for one expertly hidden clue, the writer Meghan Hicks described after joining the expedition. They found the den. Inside was Elektra and two yearling cubs. She had returned from Mexico, bred, and denned successfully in the same park that had starved her out three years earlier.
Her collar eventually failed and dropped off. Without telemetry, the team could not track her. But they knew her denning habits. In the winter of 2004, researchers visited another known den site. Elektra was inside with three new cubs. Onorato photographed one of them. The image shows a small black cub in the darkness of the den, born to a mother that had crossed a desert, crossed a river, crossed back, and found the same mountains she had left.
Image is for illustration purposes only
Source: National Park Service, Big Bend / Dave Onorato / National Parks Traveler / Onorato et al. (2004), Biological Conservation / The Revelator / Earth Island Journal.
