Jun 25

Lonesome George, a Galapagos giant tortoise believed to be the last of his subspecies, has died, according to Galapagos National Park officials.

Photo of male Abingdon Island tortoise - Lonesome George - resting

“Lonesome George”, the last of his subspecies

First seen by a Hungarian scientist on the Galapagos island of Pinta, or Abingdon, in 1972, Lonesome George became a symbol of the Galapagos Islands. With no other known individuals of his subspecies left, George had the unfortunate distinction of being considered the rarest animal in the world.

Giant tortoise declines

Galapagos giant tortoises were once so numerous that Spanish explorers named the Galapagos archipelago after them. However, these large reptiles were hunted by sailors and fishermen for their meat and oil, and more recently have suffered habitat loss and competition due to introduced goats and cattle. Introduced predators such as cats, dogs and rats also predate the more vulnerable juveniles.

Photo of Galapagos giant tortoise hatchling breaking out of shell

Young Galapagos giant tortoises are vulnerable to introduced predators such as cats and rats

There are a number of different subspecies of Galapagos giant tortoise, and the differences in appearance between the tortoises from different islands were among the features that helped Charles Darwin develop his theory of evolution.

Overall, around 20,000 giant tortoises are thought to now remain on the Galapagos Islands, but three subspecies have already become extinct or are extinct in the wild.

Photo of an old male Duncan Island tortoise in typical habitat

Duncan Island tortoise. Some Galapagos giant tortoise subspecies have “saddleback” shells, while in others the shell is more domed.

Failed breeding attempts

Despite efforts by conservationists to breed George with females from closely related giant tortoise subspecies, he sadly failed to reproduce successfully. With his death, the Pinta Island subspecies, also known as the Abingdon giant tortoise (Chelonoidis nigra abingdoni), is the latest giant tortoise subspecies to become extinct.

Lonesome George was estimated to be around 100 years old at his death, although Galapagos giant tortoises can potentially live up to 150 years or more. Park officials are due to carry out a post-mortem to determine the cause of his death.

Photo of male Abingdon Island tortoise - Lonesome George - feeding

Lonesome George feeding

Conservation efforts

Fortunately, conservation efforts are underway to save other Galapagos giant tortoise subspecies. For example, a programme running since the 1970s raises hatchlings in captivity until they are large and robust enough not to succumb to predators in the wild.

This programme has shown encouraging success, increasing the population of the Critically Endangered Hood Island tortoise (Chelonoidis nigra hoodensis) from just 13 individuals in the 1970s to over 1,000 in the wild today.

Read more about Lonesome George at BBC – Last Pinta giant tortoise Lonesome George dies.

View photos and videos of the Galapagos giant tortoise on ARKive.

Liz Shaw, ARKive Species Text Author

Feb 24

A male Rabb’s fringe-limbed treefrog, believed to be one of only two of its species left in the world, has died, bringing the population of this Critically Endangered amphibian down to a single remaining individual.

Photo of a captive Rabb's fringe-limbed treefrog

The male had been kept at Zoo Atlanta in the United States, as part of a last-ditch effort to save the species from extinction. However, following a decline in its health and behaviour the zoo took the difficult decision to euthanize the frog, both to prevent it suffering and also to ensure that invaluable genetic material could be preserved. This material may one day allow scientists to study the species further.

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, Curator of Herpetology at Zoo Atlanta.

To lose that chance would have made this extinction an even greater tragedy in terms of conservation, education and biology.”

Photo of Rabb's fringe-limbed treefrog clinging to branch

On the brink of extinction

Rabb’s fringe-limbed treefrog was first discovered by Mendelson and his colleagues during a 2005 field expedition to Panama, and was only officially described as a new species as recently as 2008.

A large frog with substantial webbing on its feet and scalloped fringes of skin along its forearms and feet, this unusual amphibian has been known to leap from treetops and use its outstretched limbs and large, webbed hands and feet to glide to the ground.

Sadly, the arrival of the fungal disease chytridiomycosis, which has begun to threaten native amphibian populations in Panama, has decimated this rare frog. Rabb’s fringe-limbed treefrog has not been seen in the wild since 2007, and is now believed to exist only in captivity.

Even if some wild individuals have survived the fungal disease, the habitat of this species is also under serious threat from forest clearance, and its restriction to one small area puts the species at particularly high risk of extinction.

Photo of Rabb's fringe-limbed treefrog

Last lonely frog

The only other Rabb’s fringe-limbed treefrog known to exist is another male, kept at the Atlanta Botanical Garden. With the loss of the male at Zoo Atlanta, this remaining individual is likely to be the very last of his species.

According to Dwight Lawson, Deputy Director at Zoo Atlanta, “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.”

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.”

Photo of Rabb's fringe-limbed treefrog, close-up of head

Global conservation effort

Amphibian populations are declining around the world, and Rabb’s fringe-limbed treefrog is not the only species to be facing extinction. Nor is it the only amphibian thought to now exist only in captivity.

Over a third of all amphibian species are currently threatened with extinction, with many facing a range of threats, including habitat loss, pollution, and the rapid spread of the deadly chytrid fungus.

Fortunately, many zoos and other organisations are working together to address this extinction crisis and to save threatened amphibian species. Although it may already be too late for Rabb’s fringe-limbed treefrog, there may still be time to bring other endangered species back from the brink of extinction.

Read more on this story in the Zoo Atlanta press release.

Find out more about amphibian conservation at Amphibian Ark.

View photos of Rabb’s fringe-limbed treefrog on ARKive.

View photos and videos of other threatened amphibians on ARKive.

Liz Shaw, ARKive Species Text Author

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