Endangered axolotl release raises hopes for rare amphibian

5 hours ago 15

Victoria Gill

Science correspondent

Victoria Gill/BBC News A captive-bred axolotl peers through glass of an aquarium in a laboratory. It has pinkish-white skin and feathery gills around its head. It appears to have a fixed smile on its face. Victoria Gill/BBC News

Very few axolotls are left in the wild

One of the world's most endangered amphibians - the strange, perpetually smiling Mexican axolotl - has thrived after being released in artificial wetlands, scientists have discovered.

In a study that provides hope for the long-term future of a creature that was pushed to the brink of extinction, scientists released 18 captive-bred axolotls in restored and artificial wetland close to Mexico City.

The researchers fitted the animals with radio trackers and found that they "survived and foraged successfully at both sites" - even gaining weight.

Lead researcher Dr Alejandra Ramos from the Autonomous University of Baja California said this was an "amazing result".

Victoria Gill, BBC News A wild axoltol in a captive breeding programme aquarium. In contrast to pet and laboratory axolotls, this wild amphibian is brown and mottled. The image shows how well camouflaged the animal is against the dark rocks and mud of its natural wetland habitat. Victoria Gill, BBC News

The researchers are captive-breeding axolotls for release into the wild

The findings are published in the journal PLoS One and they suggest, the researchers say, that the axoltol can be brought back to its native habitat.

The waters of Xochimilco - shaped by traditional farming practices and flushed with spring water from the mountains - used to teem with these amphibians.

But as Mexico City grew, urbanisation, pollution and other pressures pushed axolotls to the brink of extinction, with some estimates suggesting that there were as few as 50 left in the wild.

"If we lose this species, we lose part of our Mexican identity," said co-lead researcher Dr Luis Zambrano from the National University of Mexico.

It is no exaggeration to call the axoltol an icon. Aztec legend has it that the creature is a god in salamander form - the Aztec god of fire and lightning, Xolotl, disguised as a salamander.

"If we can restore this [wetland] habitat and restore the axolotl's population in a city of more than 20 million people," Dr Zambrano continued, "I feel that we have hope for humanity."

Victoria Gill, BBC News The scene shows a traditional wetland farming site in Xochimilco, close to Mexico City. This is the natural home of the axolotl - it is green and verdant with vegetation, there are crops growing and there is a murky canal in the foreground. This is one of the sites of ongoing habitat restoration for the Mexican axolotl. Victoria Gill, BBC News

The wetlands of Xochimilco used to teem with axolotls, but they have been almost wiped out by pollution

To lay the foundations for releasing the animals, the researchers worked with local farmers and a team of volunteers to create wetland "refuges" for the axolotls. They installed natural filtering systems to clean the water,

The scientists released their captive-bred animals at two sites - one in Xochimilco and one at a disused quarry that, over decades, has turned into what they called an "artificial wetland".

Every animal was tagged with a radio tracking device.

"The amazing news is that they all survived," Dr Ramos told BBC News. "And not only that, but the ones that we recaptured had gained weight - so they're hunting."

The monitoring also revealed intriguing insights into axolotl behaviour. "We found that some spend most of their time with with one other individual - like they make these little friendships," Dr Ramos explained.

Victoria Gill/BBC News The image shows a man (on the left) and a woman smiling into the camera. Both are scientists working on conservation of the wild axolotl in Xochimilco, close to Mexico City. The background shows the lush, green habitat that is their field site. Victoria Gill/BBC News

Scientists Luis Zambrano and Alejandra Ramos in Xochimilco

Somewhat ironically, these charismatic salamanders are found in the world's laboratories and pet aquariums in their hundreds of thousands. The species is biologically fascinating - it has the remarkable ability to regrow any part of its body that is damaged or lost. So there is research underway to understand whether that ability could be harnessed medically.

But in the murky wetlands of Mexico City, there is still a great deal of work to do to clean up and restore the habitat, and to give the wild axolotl a chance to recover.

"Many animals are losing their habitat around the world," said Dr Ramos. "And restoration projects are not easy, but they can be done - they just need a lot of people.

"You don't need to be a scientist to get involved - everybody in the world can help out."

David Schneider The scene shows a green, farmed landscape with waterways running through it. There are small, traditional farms called chinampas in the foreground and mountains in the background. This is the native habitat of the Mexican axolotl David Schneider