Toughie, the only Rabbs' fringe-limbed treefrog left on Earth, probably doesn't know that he's the last of his kind. But his caretakers at Atlanta Botanical Garden do.

The call of the Rabbs' fringe-limbed treefrog hasn't been heard in its natural Panamanian habitat since 2007, shortly after a deadly fungal pathogen cut through the population. The only other known member of the species died in February of last year at Zoo Atlanta.

So what's it like to work with the last of an entire species?

Jennifer Cruse-Sanders, vice president for science and conservation at the Atlanta Botanical Garden, knows this responsibility is a special one. "This frog represents a species that, in the span of the last five years, has both been discovered and reached the brink of extinction," she said.

Toughie's species was named in honor of lifetime conservationists George and Mary Rabb. Their cause motivates the science and conservation team to not only help Toughie survive, but also to learn from his situation and apply it to other species of the vulnerable amphibian world.

"For me it is incredibly motivating working with the Rabbs' frog," said the botanical garden's amphibian specialist, Leslie Phillips. "Having him here is a constant reminder of what can potentially happen to other species if we don't continue the conservation work that we do here at the Atlanta Botanical Garden."

The team visits Toughie frequently at his wet tree hideaway to monitor his health. Cruse-Sanders says Toughie is "alert and active" when they interact with him.

"Honestly, it is also nerve-racking at times working with him," Phillips admitted. "It can be a challenging balance between leaving him alone as much as possible to avoid undue stress, while still providing the best possible care."

Yet the frog continues to charm Phillips.

"He is just really cool," Phillips said. "No other frog I have seen is quite like him. He is muscular and has giant webbed feet and big eyes ... He is a very handsome frog."

Those attributes went a long way in the wild, allowing for Rabbs' fringe-limbed treefrogs to glide between trees and down to the forest floor. Males like Toughie were known to be fierce protectors of the tadpoles, uniquely using their own bodies' skin cells to feed their young.

Toughie sure has lived up to his name. Perhaps others of his species have, too.

"We hope that there is still a possibility that one day this species will be rediscovered in nature," Cruse-Sanders said.

Until then, he perseveres.

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Taking care of Toughie, the last of his kind
The last Rabbs' fringe-limbed treefrog on Earth lives at Atlanta Botanical Garden. In the frog, his caretakers see hope and a huge responsibility.