Updated

Mexico's salamander-like axolotl (ACK-suh-LAH-tuhl) may have disappeared from its only known natural habitat in Mexico City's few remaining lakes.

It's disturbing news for an admittedly ugly creature, which has a slimy tail, plumage-like gills and mouth that curls into an odd smile.

The axolotl is known as the "water monster" and the "Mexican walking fish," and its only natural habitat is Lake Xochimilco (zo-chee-MILL-co), which is suffering from pollution and urban sprawl.

Biologist Luis Zambrano of Mexico's National Autonomous University says the most recent three-month attempt to net axolotls found not one of the creatures. He says researchers are planning a second three-month hunt for the creatures, which still survive in labs and breeding tanks.