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The population of a unique Mexican amphibian drops 90 percent in four years

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axolotlUrban growth is quickly driving one of the world’s most bizarre creatures into extinction. According to a new study, the axolotl (Ambystoma mexicanum), a Mexican amphibian that never metamorphoses past its larval stage, has seen a 90 percent population drop in the last four years. Only an estimated 700 to 1,200 axolotls now remain. The species was already listed as critically endangered on the IUCN Red List of Threatened Species.

The study, led by Luis Zambrano González of the National Autonomous University of Mexico in Mexico City, was published in the August 18 edition of the journal Biological Conservation.

The axolotl exists only in the Xochimilco region of Mexico, in an area just 10 square kilometers in size. The region supplies much of Mexico City’s water, and the study found that water quality in the region has declined in the past decade as the metropolis has expanded, putting pressure on the axolotl’s sole habitat.

Introduced aquatic species like carp and tilapia have also created competition for the axolotl’s food supply. They also eat the amphibian’s eggs.

Despite (or perhaps because of) its rarity, the species remains a popular pet, although most breeding for the pet trade is conducted in captivity. Axolotls are also commonly used in scientific research due to their ability to regenerate lost limbs.

By the way, that estimate of 700 to 1,200 axolotls belies the fact that recent surveys on 11 sites in the Xochimilco region "found only a single organism in the whole study region," according to the study’s abstract, which suggests "a critical situation for the long-term survival of the axolotl in the wild, and demanding urgent actions toward habitat and population restoration."

Image: Axolotl via

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  1. 1. DrJohnClare 1:51 am 08/29/2009

    Hello, I’m the author of the pet site you have kindly linked (

    "Despite (or perhaps because of) its rarity, the species remains a popular pet, although most breeding for the pet trade is conducted in captivity."

    To the best of my knowledge _all_ Ambystoma mexicanum / Axolotls in the pet trade outside of Mexico are captive bred. This is one of the rare instances where the international pet trade can have a clean conscience, having put zero pressure for decades on an animal popular in captivity.

    Link to this
  2. 2. hotblack 1:22 pm 08/29/2009

    What an interesting species. …to be replaced by… carp. Great.

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  3. 3. Biodiversivist 3:12 pm 08/29/2009

    My youngest daughter has kept two of them for many years now. She also has a New Caledonia Crested Gecko, once thought extinct in the wild. Ironic that creatures that do well in captivity may be saved from extinction.

    Link to this

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