Saving the Panther

The Florida panther’s journey back from the brink of extinction started a few days earlier than expected.

TX-104 was a female mountain lion flown from West Texas in March of 1995 to mate with male panthers and give a boost to the dwindling panther population. The 4-year-old cat was supposed to spend about a week in an enclosure amid the cypress and swamp dogwood trees of Fakahatchee Strand Preserve State Park to acclimate to her new South Florida home. But when her handlers brought her water just one day after her arrival, TX-104 bolted and escaped into the wilds of the Everglades.

Though conservationists and biologists had worked for years to get to that point, they weren’t especially concerned about the animal’s breakaway. Before the mountain lion took off, they had fitted her with a radio collar, so wherever she went, they’d be able to find her.

Over the following weeks, seven more female lions were released into the Everglades in one of the most controversial interventions in wildlife management history. Twenty-three years later, the panther is by no means out of the proverbial woods, but its numbers have increased tenfold, the population is exhibiting fewer genetic defects and the animals are expanding into new areas. Criticism of the operation has largely died down, and many of those involved in the original intervention now view the release of the Texas mountain lions as an unmitigated success.

“In the annals of species recovery, this would be one of the gold-star ones,” said Oron “Sonny” Bass, a recently retired wildlife biologist at Everglades National Park.

The panther’s range once covered a vast territory from Louisiana to South Carolina, but habitat degradation and hunting brought the animal close to extinction. In 1967, the Florida panther was listed as an endangered subspecies of the animal known as cougar, puma or mountain lion in other parts of the country. Some thought the animal no longer existed in the wild, but then Roy McBride, a Texan tracker hired by the World Wildlife Fund, found one female near Lake Okeechobee in 1973. By the early 1990s, official estimates put the number of wild panthers between 30 and 50. Bass thinks fewer than 20 remained. “The population was going to die out,” Bass said.

The panther’s isolation had also led to extensive inbreeding, and many of the remaining animals exhibited abnormalities such as kinked tails, heart defects or reproductive problems. To address the felines’ genetic issues, panther specialists started to consider bringing close relatives of the panther to Florida so they could produce healthier offspring. It was a radical idea: A genetic rescue of a large mammal had never been undertaken anywhere in the world. Even today, such interventions remain extremely rare. To weigh the pros and cons of the proposed operation, geneticists and biologists from various state and federal agencies convened three workshops between 1991 and 1994.

Some critics of the plan argued that the low population of panthers was appropriate for the available habitat and that a rescue was unnecessary. Others wondered whether the offspring of a Florida panther and a Texas mountain lion would still be a Florida panther. The two subspecies had mated naturally when the panther’s range had extended much farther west, but that hadn’t happened for a century or so. “It was a very controversial intervention,” said Stuart Pimm, a conservation ecology professor at Duke University and an expert in the study of present-day extinctions. “There were many people who thought it was a bad idea.”

Eventually, the U.S. Fish and Wildlife Service ruled that the hybrids between Texas mountain lions and Florida panthers would receive the protection of the Endangered Species Act, and the plan was approved. McBride, the Texan trapper, was tasked with capturing the eight cats. There was just one problem: No money had been set aside for the transportation of the animals to Florida. “So we said, ‘We’ll pay for it.’” said Will Callaway, then NPCA’s point person on the project.

The Texas mountain lions were released over the spring and summer of 1995 in various South Florida locations, including Everglades National Park and Big Cypress National Preserve. Biologists followed the movements of the radio-collared cats by plane. One of them gave birth to a couple of kittens just a few months after her release, and over the next eight years, five Texas cats produced at least 20 kittens. Bass and his colleagues tracked and studied the new generation and found the evidence they were looking for: The young animals were much healthier than their Florida fathers. “The big, big difference was the survivorship of the kittens,” said Pimm, who, along with Bass and another biologist, published a study on the impact of the mountain lions on the panther population.

Among the Texas eight, five died of various causes including vehicle collision, pneumonia and pregnancy complications. TX-104, the escape artist, died from gunshot in 1998. The remaining three were removed from the wild so they wouldn’t contribute too much Texan DNA to the population.

Today, descendants of the Texas females make up a sizable portion of the 120 to 230 adult panthers that live in the Everglades. The panthers have expanded into new habitats, and last year, kittens were spotted north of the Caloosahatchee River for the first time in decades, giving biologists hope that a second population could be established in Southwest Florida — a key milestone in the panther’s path toward recovery.

Plenty of challenges remain. The population of Collier County, where much of the panther’s habitat lies, is booming, and development there is “a huge threat to remaining viable habitat,” said Cara Capp, NPCA’s Everglades Restoration program manager. Each year, about two dozen panthers are killed on Florida’s roads. Though there has never been a documented panther attack on a human, some residents are wary of sharing their backyards with the area’s top predator.

Larry Williams, the leader of the Fish and Wildlife Service’s panther recovery team, knows all this but is still optimistic. “That’s been a 40-year undertaking,” he said, “and it’s working.”