Thursday, January 5, 2012

Axolotl – The Salamander that Never Grows Up

Most salamanders are born as aquatic animals without legs or lungs and must undergo a metamorphosis to develop these essential body parts on their way to becoming land-dwelling adults. While the shape, size and characteristics of adults vary greatly over the roughly 500 species of salamanders, most undergo dramatic changes from birth to adulthood.

However, one salamander native to a few Mexican lakes never really grows up; the axolotl. Even after reaching adulthood axolotls still remain aquatic with gills and underdeveloped legs, usually resembling the larval stage of several other salamanders that eventually grow to live on land such as waterdogs.
Though there are other salamanders that keep their youthful shapes throughout life, the axolotl is the only species that is able to transform itself into a land-dwelling salamander with working limbs and lungs if conditions warrant. In most cases this will never happen, however if the animal’s water habitat starts to slowly drain and it is no longer able to submerge itself, it can transform in a matter of weeks. Scientists have also been able to induce this by injecting captive axolotls with iodine.
Though many exist in captivity, the axolotl is critically endangered in the wild. Lake Chalco, one of its two native habitats, has already been drained. The only remaining body of water in which it lives, Lake Xochimilco, has been largely drained and heavily polluted by the growth of Mexico City; though a protected area on the lake has been established to hopefully save this very unique animal. 

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