A rare tree frog — the last documented member of a species relatively new to science — has died at the Atlanta Botanical Garden.
The body of the Rabbs’ fringe-limbed tree frog was discovered in its enclosure Monday morning during a routine daily health inspection.
Staff at the garden nicknamed the long-lived amphibian “Toughie.” He was estimated to be about 12 years old.
Amphibian specialist Leslie Phillips told the Mother Nature Network that she was charmed by the frog. “He is just really cool,” Phillips said in a 2013 interview. “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.”
Atlantans are particularly distressed by the loss, which comes after the Botanical Garden, Zoo Atlanta and Southern Illinois University joined forces in a rescue attempt of the species.
In 2005, the three groups sent a team of scientists to Panama to collect live animals before a disease called chytridiomycosis struck the area. Among the frogs they brought back to Atlanta was a species of tree frogs (Ecnomiohyla rabborum) that hadn’t been seen before. Identified in 2005 by Zoo Atlanta herpetology curator Joseph Mendelson, it was later named for conservationists George and Mary Rabb. In time, the disease did arrive in Panama, and many of the frogs disappeared.
In 2008, the Atlanta Botanical Garden purchased and outfitted a climate-controlled facility known as the Frog Pod, designed to house the Rabbs’ tree frog and other rare amphibians in complete isolation from each other. It is in this facility that the Rabbs’ frog spent the last eight years of his life.
“Science had a very short window to learn about the species in the wild before this disease struck the only known locality for the frog and the species vanished,” said Mary Pat Matheson, the garden’s president and CEO. Matheson said the garden had successfully bred its male with a female from Zoo Atlanta, but that the tadpoles did not survive.
Zoo Atlanta’s last two remaining Rabbs’ frogs, a male and a female, died in 2012. In the absence of a female, Toughie ceased his distinctive song, a kind of measured, birdlike cawing.
Because the frog was the last of the species, the garden had its body cryogenically frozen and delivered to the Cryogenics Division of the San Diego Zoo Global Institute for Conservation Research. That measure helps preserve information about the species that would otherwise be lost. Unfortunately, said Matheson, it also precludes an opportunity to determine the cause of death.
Scientists estimate that one-third to one-half of amphibian species worldwide are threatened with extinction, many due to habitat loss and the chytrid disease, which is caused by an aquatic fungal pathogen.
The loss of frogs around the world has a greater impact than one might imagine, Matheson said. Frogs lay eggs by the thousands, which serve as a food source for birds, reptiles, fish and other amphibians. Tadpoles consume algae, keeping rivers and creeks clean, reducing mosquito populations and slowing the spread of malaria.
Matheson spoke to George Rabb after Toughie’s death, expressing the hope that another specimen might be found in Panama, but Rabb said the odds were low.
The scientists in Panama would have heard the tree frog’s distinctive song, he said, but that song was silenced.