In the murky waters of pre-Columbian canals in southern Mexico City lurks a creature that's seemingly straight out of ancient mythology: the Mexican salamander, or "Axolotl."
Named after a godlike water monster that was worshipped in Aztec times, the Axolotl could hold the secrets to slowing the aging process and regeneration of human limbs. For decades, a team of international scientists has been working methodically to sequence part of the Axolotl’s genetic code in hopes it can be applied to modern medicine. But now they're racing the clock.
Despite its international fame, this curious creature is at risk of extinction; there are now more of them living in laboratories than in the ancient waterways of Xochimilco.
Unlike other salamanders that can regenerate limbs, the Axolotl can also regrow a new heart, liver and even parts of its brain. That unique ability has drawn teams of international scientists for over a century. But the learning curve has been steep.
After all this time, scientists still don’t know how the Axolotl does it, according to Alfredo Cruz, the head of the Molecular and Developmental Complexity Laboratory at LANGEBIO-CINVESTAV, a Mexican biodiversity research center. Cruz, who's been studying the Axolotl for the past three years, told Fusion this little water monster is among the most fascinating creatures on earth.
"We started working with the Axolotl because it is the vertebrate model species with the greatest capacity for regeneration on the planet," he said. Unlike other types of vertebrates, the Axolotl never loses its ability to regenerate parts of itself, thanks to it's unique genetic make up, says Cruz.
“Almost all vertebrates in their embryonic stage are able to regenerate limbs or tissues, including humans, because we have active groups of stem cells," Cruz explains. "The difference is that the Axolotl, even after its embryonic stage, maintains that ability, while other organisms lose the genetic information which would allow us to regenerate.”
“If we could find some basic molecules that exist in both the Mexican Axolotl and humans, we would have ideas on how to implement limb regeneration in humans," Cruz said.
The Mexican salamander has survived over the years and adapted to climate change by keeping its head down and its feet wet.
“Their whole life was lived in the water, because they perceived risks outside of the canals,” Cruz explained.
But now those risks have spread to the water itself. In the 1970s, the Mexican government introduced carp and tilapia, a notoriously aggressive African fish, into the canals to provide income and food for local fishermen. But the new species developed a taste for Axolotl and started to decimate the salamander population. The 2 million visitors to the canals every year have also contributed to large-scale pollution of the waterways, pushing the Axolotl to the brink of extinction.
Luis Zambrano, an ecology and aquatic habitats specialist at the National Autonomous University (UNAM), says the Axolotl population surpassed 100,000 specimens per square kilometer 17 years ago. Now they’ve all but disappeared.
Now a rescue plan is underway. Biologists from the Biological Research Center and Aquaculture (CIBAC), are breeding and introducing the animal into a artificially created clean lake within the Xochimilco canal system.
Biologist Fernando Arada says the group breeds around 4,000 Axolotl per year. Over the past three years they’ve released some 2,500 salamanders into the lake. They don’t know how many Axolotl have survived, but there are enduring signs of an enduring population, scientists say.
It’s good news for science, but the original population of Axolotl in the polluted canals Xochimilco canals could be – pardon the pun — on its last legs.