The world’s most endangered frog – Just 1 known animal left

Rabb's Tree frog - The last existing known specimen. Courtesy of Zoo Atlanta.

February 2012 - Amphibian populations are declining around the world, to the extent that some of the last survivors of Central America's once rich diversity of frogs now exist only in captivity. A male Rabbs' fringe-limbed tree frog, believed to be one of only two of his kind left on Earth, has died at Zoo Atlanta.

Following a marked decline in his health and behaviour, the Animal Management and Veterinary Teams made the difficult decision to euthanize the frog to prevent suffering and to preserve invaluable genetic material that may someday be used to study the species, which is now believed to be extinct in the wild.

"Amphibians decompose much more rapidly than do many other classes of animals. Had the frog passed away overnight when no staff members were present, we would have lost any opportunity to preserve precious genetic material," said Joseph Mendelson, PhD, Curator of Herpetology. "To lose that chance would have made this extinction an even greater tragedy in terms of conservation, education and biology."

Extinct in the wild
Named for noted amphibian conservationists George and Mary Rabb, the species was first identified by Mendelson and an international team of colleagues following a 2005 field expedition to Panama, where a pathogen known as amphibian chytrid fungus had begun to threaten native amphibian populations. Since that discovery, the fungus has eradicated entire amphibian species in the wild, including the Rabbs' fringe limbed tree frog, which has not been observed in the wild since 2007. The last known member of this species, another male, resides at the Atlanta Botanical Garden.

"This is the second time in my career that I have literally seen one of the very last of its kind die and an entire species disappear forever with it. It is a disturbing experience, and we are all poorer for it," said
Dwight Lawson, PhD, Deputy Director. "The ongoing amphibian extinction crisis has taken a rich diversity of animals from us, and more effort and resources are desperately needed to halt the losses."

Home to one of the nation's finest collections of reptiles and amphibians, many of them endangered or critically endangered, Zoo Atlanta is a leader in the effort to combat the crisis of global amphibian decline. Mendelson, who is responsible for the naming of more than 30 new amphibian and reptile species, also serves as President of the Society for the Study of Amphibians and Reptiles and is on the faculty at the Georgia Institute of Technology.