And then there were none.

Toughie, the world's last Rabbs' fringe-limbed tree frog and a symbol of the extinction crisis, has died at his home in the Atlanta Botanical Garden.

The famed frog's age is unknown, but he's at least 12 years old, and likely older, because he was an adult when collected in 2005.

Mark Mandica, who worked with Toughie for seven years, says the frog's story isn't entirely unique. “A lot of attention had been paid to him in captivity, so he even has his own Wikipedia page,” Mandica, head of the Amphibian Foundation, notes. “But there are plenty of other species out there that are disappearing, sometimes before we even knew that they were there.”

In fact, Toughie's own species (Ecnomiohyla rabborum) wasn't described until 2008, a few years after Toughie was found during a 2005 frog rescue mission by the Atlanta Botanical Garden and Zoo Atlanta. He was one of many frogs scientists raced to collect as the deadly chytrid fungus closed in on central Panama.

“It was likened to just rescuing things from a burning house,” Mandica says.

The species occurred in a very small range, at an elevation where the fungus proved especially deadly. Field studies suggest up to 85 percent of all the amphibians on Toughie's home turf were wiped out. It's unlikely that any of his kind survived in the wild, where they were incredible climbers and also graceful gliders—toe webbing allowed them to soar from one tree to the next. (Learn about the increasing pace of extinctions.)

Watch: This tree frog's death marks the end for a species.

Naming a Survivor

Mandica's son, then a two-year-old, dubbed the last survivor Toughie. Naming animals isn't the norm among scientists, but the frog's popularity as the last of his kind meant that people (and the press) kept demanding a name—and Toughie stuck.

Although he gave voice to the plight of endangered species, Toughie was silent for all the years he lived at the botanical garden, until one fateful morning in 2014 when Mandica captured the only existing example of the Rabbs' fringe-limbed tree frog's call.

“I heard this weird call coming out of the frog [area], and I knew it had to be him, because I knew what all the other species sounded like. I was able to sneak in and record him on my phone.” (Hear Toughie's call.)

View Images Toughie was photographed in his captive home at the Atlanta Botanical Garden. Photograph by Joel Sartore, National Goegraphic Photo Ark

Atlanta Botanical Garden

Photographing the Last of a Kind

Photographer Joel Sartore recalls a curious, baseball-size creature with amazing eyes that actually hopped up onto his camera while being photographed for the Photo Ark project. Photo Ark aims to showcase our planet's incredible biodiversity and inspire people to help fight the extinction crisis while there is still time. So far, Sartore has photographed more than 6,000 species. Unfortunately, many others also represent the end of the line for their kind.

“About once a year I photograph something that's the last of its kind or close to it,” he says. “I get sad and angry because I can't imagine that this won't wake the world up and get people to care about extinction. I keep thinking, OK, this is the one. This animal's story is going to do it and get people to care more about extinction than about what's on TV.

“They can't care if they don't know these animals,” he adds. “They have to meet them and fall in love with them the way that I have and so many others have.”

Watch: Scientists rush to save other tree frogs in Central America.

Toughie, indeed, had lots of admirers. Last year his image was even projected onto St. Peter's Basilica, and his call played, so that the world could see and hear him.

The frog met race car drivers and movie directors, Sartore recalls. “A lot of people were moved to tears when they saw him. When you have the very last of something it's a special deal.”

Now he's gone, and with him an entire species. And as large numbers of animals and plants continue to vanish, their loss increasingly compromises the healthy ecosystems necessary for everyone's survival—including our own. (Can extinct species ever be brought back?)