They might have some pretty awesome superpowers (like the world's cutest amphibian smile, eternal youth, and the ability to regenerate lost limbs – and lungs, spinal cords and even bits of brain!), but the alien-looking axolotls seem to be losing the battle for survival in just a few of Mexico City's increasingly polluted lakes and canals, their only remaining natural habitat.

31 01 2014 Lake Xochimilco Mexico
The increasingly polluted lakes and canals of Mexico's Xochimilco district are all that is left of the axolotl's natural habitat. Image: spotreporting, Flickr

The Telegraph reports that a recent three-month search for the creatures conducted by biologists from Mexico's National Autonomous University ended without success: not a single specimen was netted. That's a drastic decline from the vast populations that once inhabited the ancient system of water channels and lakes on the southern edges of Mexico City. 

The strange-looking amphibians (sometimes called 'water monsters' or the 'Mexican walking fish') still survive in captivity, but their habitat in the wild has been wrecked by pollution and urban sprawl. Mexico City's Lake Chalco, which once made up a good chunk of the axolotl's natural habitat, has basically vanished over the course of the 20th century, having been drained to avoid flooding and to make room for urban expansion. Overharvesting by humans (and the introduction of invasive predatory fish like tilapia and carp) has also driven the axolotl's decline. In 2006, the IUCN listed the species as Critically Endangered.  

“So is it all over for free-roaming axolotls? The reseachers are not ready to give up yet.”

So is it all over for free-roaming axolotls? The researchers are not ready to give up yet. Next month, they will once again hunt for the creatures in the murky canals of Mexico City's Xochimilco district, this time hoping for more success – axolotl breeding season is about to begin, making any remaining survivors easier to locate. And to help the tiny amphibians cling on to survival, certain Xochimilco canals have been cleared of invasive species and filtered to reduce pollution, creating axolotl 'sanctuaries'.

Here's hoping everyone's favourite smiling 'water monsters' can still make a comeback.  

Top header image: Michelle Bender, Flickr