In 2009 scientists reported that the population of one of the world's most bizarre creatures has dropped by 90 percent over the previous four years. Flash forward four more years and it now appears that Mexico's "water monster" is approaching extinction in the wild.

Species name: Axolotl (Ambystoma mexicanum), also known as the "water monster" and "Mexican walking fish." These unusual salamanders never undergo metamorphosis and stay in a larval form their entire lives.

Where found: A new study found no evidence that the axolotl still exists in its sole habitat, a 10-square-mile region outside of Mexico City. Another survey will begin later this month in hopes that the axolotl can still be found. The scientists say it is premature to declare extinction, but things definitely aren't good.

IUCN Red List status: Critically endangered

Major threat: Development. Mexico City has tapped much of the water supply in the Xochimilco region, reducing the supply available to the axolotl. Much of the region has been converted in shantytowns, and the resultant raw sewage has poisoned the remaining water. The species also faces threats from introduced species.

Previous Extinction Countdown articles about this species: From 2009: Population of Unique Mexican Amphibian Drops 90 Percent In Four Years

Notable conservation programs: Even if the axolotl is extinct in the wild, it isn't gone quite yet. Quite a few of the amphibians live on in the pet trade, while some labs hold small collections so researchers can study the animals' ability to regenerate lost limbs. Several zoos, including Toronto Zoo and Chapultepec Zoo, have been working to preserve the species and its habitat.

Multimedia: Here's a cute little axolotl in someone's aquarium:

And here's a great video about the axolotl from the Ugly Animal Preservation Society:

Photo by Josh More via Flickr. Used under Creative Commons license

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