Excerpted with permission from Resurrection Science: Conservation, De-Extinction and the Precarious Future of Wild Things, by M. R. O’Connor. Available from Saint Martin’s Press. Copyright © 2015.(Scientific American and Saint Martin’s Press are part of Holtzbrinck Publishing Group.)

The puma is a cat with many names. Catamount, cougar, mountain lion. In the southeastern United States, pumas are called panthers, and in the early 1970s there were two camps among biologists when it came to the question of whether any were still living. The first camp believed the subspecies had completely disappeared. Colonizers in this part of the country beginning with the Spanish conquerors saw the animals as a menace and killed them accordingly. Bounty laws awarded anyone who killed a panther and could prove it with a scalp; in 1887 a dead panther was worth $5. Meanwhile, hunters, squatters, and sprawling agriculture wore down deer populations, the staple of the panther diet. The result was that by the end of the nineteenth century Puma concolor coryi, the sleek animals that had once roamed from the bottom of South Carolina to Tennessee, Arkansas, and Louisiana, had nearly vanished. “The exact range of the form cannot now be given, as the puma is extinct in the region directly northeast of Florida, and I believe northern Florida as well,” reported a member of the Boston Society of Natural History in 1898. “None have been seen in eastern Georgia for many years.”

The second camp thought that some cats—maybe as many as 300—might have found a way to survive off feral hogs in the forests and swamps of southern Florida, places where agriculture was near impossible in the acidic soil and development was limited by the brutal heat and humidity of the tropical landscape. There was some evidence to support this idea. In 1969, a deputy sheriff killed a 100-pound male panther near the town of Inverness in central Florida. Three years later, a highway patrolman shot and killed a panther east of Lake Okeechobee after a car injured it. Based on these encounters, there was reason to believe there could be a larger remnant population of the subspecies still eking out an existence in Florida’s wilderness.

Around 1972 the World Wildlife Fund (WWF) decided to find out. It was just one year before Congress would pass the Endangered Species Act. Florida law had fully protected the panther from hunting since 1958, but would the cat be listed under the new federal law as threatened? Endangered? Extinct? The environmental organization reached out to a taxonomist in Florida, who in turn contacted a predator hunter and tracker in Texas by the name of Roy McBride.

McBride was an unlikely character to be hired by a group of conservationists interested in the survival of panthers. The author Donald Schueler in his 1991 book, Incident at Eagle Ranch, presented a rare portrait of a private man who avoids the public eye. “During his younger days,” wrote Schueler, “he had more to do with bringing the mountain lion to the verge of extinction in Texas than any other single person. Given his remarkable stamina and the quality of his pack of hounds, a lion ‘almost never gets away’ once McBride goes after it.” “Let McBride do it” was the motto when a particularly wily predator was amok and needed capturing.

McBride used a variety of means to take an animal. If he didn’t have an effective tool at his disposal, he invented it. In the 1970s he was having difficulty trapping a coyote on a sheep ranch. He imagined that if he could put a trap where the animal attacked the sheep’s neck, he had a foolproof way of catching a hungry coyote. Of course he couldn’t attach a trap so instead he created a collar with poison that could be attached to the sheep’s neck and would kill the coyote. McBride turned his patented collars into a family business near his home in Alpine, Texas. When President Richard Nixon signed an executive order restricting the domestic use of the poison known as Compound 1080—a popular substance with no odor or taste used for decades to poison large predators, and used in McBride’s collars—he sold them to ranchers in Mexico, Canada, Argentina, and South Africa.

In addition to his work in the United States, McBride had traveled for years throughout Mexico as a contracted wolf hunter. He spoke Spanish fluently and rode on horseback to track the animal called “El Lobo” for ranchers who needed to protect their livestock. When Cormac McCarthy was writing The Crossing in the 1990s, the second book of his Border Trilogy series, he found inspiration for the story of a haunted sixteen-year-old boy trying to catch a wolf in McBride’s tale of spending eleven months hunting a single wolf in Mexico. Among hunters and naturalists in the Southwest, the story is the stuff of legend.

The male wolf called “Las Margaritas” had lost two toes on its left front foot from an encounter with a trap. In the late 1960s, he was killing dozens of yearling steers and heifers on ranches along the Durango-Zacatecas border. “The wolf seldom used the same trail twice and if he came into a pasture by a log road, he left by a cow trail,” wrote McBride in a government report in 1980. “I was sure I could catch Las Margaritas, but I couldn’t get him near a trap.” McBride tried baited traps and blind traps, traps boiled in oak leaves, and traps concealed in carefully sifted dirt. Nothing worked. Over months of intensive effort, McBride had managed to get the wolf close to a trap just four times. He traveled thousands of miles on horseback trying to understand the animal’s uncanny ability to elude him. “Almost a year had passed and I was now convinced that I would never catch this wolf,” he wrote. “Just how the wolf could tell the traps were there is something I cannot comprehend to this date.” At times, however, McBride had noticed that Margaritas had passed at campfires along the road, places log- truck drivers had stopped along the way to cook. “I set a trap near a road that the wolf was sure to come down if it continued to kill in the area, built a fire over the trap and let it burn itself out.” McBride put a piece of dried skunk hide in the ashes from the fire and waited. One day in March, the wolf caught wind of the setup and went to investigate. The trap caught him by his crippled foot.

Wolf lovers and conservationists might shudder at the story of a man hunting down what we now know was one of the few remaining individuals of the Mexican gray wolf species in the wild. But McBride’s legacy is more complex than that. In 1976 the Mexican gray wolf was listed as endangered under the Endangered Species Act, and the US Fish and Wildlife Service (USFWS) Office of Endangered Species hired McBride to find out whether any of the wolves the government had once tried to eradicate had survived in Mexico. He found some twelve wolves in the state of Durango and half a dozen in the state of Chihuahua.  In all, he estimated as many as fifty individuals in all of Mexico might still be living, but the possibility of the species being saved in the wild was, in his opinion, impossible. The next year he trapped six gray wolves—two in Sierra del Nido in Chihuahua and four near Coneto in Durango—and delivered them for a government captive breeding program in Tucson, Arizona, with the goal of bringing them back to the landscape. “It was a change in policy, to say the least,” he told me. “They were the guys who killed them and then they tried to reintroduce them.” After years of political controversy, bureaucratic turmoil, and fluctuating populations, around eighty Mexican gray wolves roam the Southwest today, more than at any time since the government reintroduced them to the wild in 1998. These wolves descend from just seven wolves representing three captive lineages: the Aragón, Ghost Ranch, and McBride. The McBride lineage, because of greater genetic variation, constitutes over 70 percent of the present-day population’s genetic ancestry.

Of course in 1972, when the WWF hired McBride, his reputation was not as someone who had played a critical role in salvaging an endangered species from the brink of extinction, but rather as a formidable tracker. If anyone could find out whether any Florida panthers had managed to survive a 500-year onslaught on their existence, it was him.

McBride arrived in Florida with his pack of hounds. He started in Highlands County near Lake Istokpoga and worked his way south over the next several weeks, ending up in Big Cypress National Preserve. He didn’t see panthers but he found evidence of some. “Not many,” he would say later, “but a few.” The next year he repeated the same survey and near Fisheating Creek, southwest of Lake Okeechobee, his pack treed a panther, an older female, infested with ticks and in poor condition. It appeared that she had never produced kittens.

McBride began teaching Chris Belden, a state biologist, how to spot panther signs such as paw prints, urine markers, and droppings. In 1974, they found evidence that two panthers were living in the Fakahatchee Strand. Based on their searches, McBride and Belden thought that as many as twenty or thirty panthers were still alive, living off deer and feral hogs in the areas around Lake Okeechobee and south into the Everglades. “I was amazed to find them,” McBride would say in 1994. “I mean, I got down here in this thickly settled area, and I was really surprised there was any left.”

His discovery launched the Florida Panther Recovery Team in 1976. Its task: to come up with a plan to save the Florida panther from extinction.