One of the most famous and bizarre natives of Mexico City is the axolotl. Dubbed locally as “water monsters,” these 20-cm-long, soft-skinned water dwellers possess biological traits that are just as strange as their whimsical appearance suggests. These are traits that have attracted the attention of scientists all around the globe. Unfortunately, this fascinating species is on the brink of annihilation in the canals of Mexico City, its only natural habitat.
Axolotls are unusual in that unlike most amphibians, they do not metamorphose into lung-breathing, earth-walking adults. While some of their peers transform into earth-walking salamanders after losing their tadpole-like tails and gills from their heads, axolotls retain their juvenile characteristics throughout their lives, living a fully aquatic lifestyle with a finned tail and frilly gills. Scientists have found that they could force axolotls in the lab to metamorphose by injecting them with thyroid hormones, but these transformations rarely happen in the wild.
Their most intriguing trait, however, is their potent regenerative ability. Scientists have long been fascinated by how axolotls are able to regrow almost any body part. They can regenerate severed limbs, tails, and even parts of the heart and brain. Moreover, all kinds of organs, even eyes, can be transplanted between axolotls without rejection by the recipient body’s immune system. In one memorable experiment, scientists discovered that they could even transplant the head of one axolotl to another. What’s more, they appear to have a resistance to cancer. Scientists believe that the answer to tissue repair and cancer could be found in the species’ impossibly large genome.
Despite the deep scientific interest in the species, axolotls are critically endangered and their population is rapidly declining. Pollution especially has been detrimental to the continuation of the strange aquatic creatures. Axolotls, with their highly permeable skin, are especially vulnerable to the trash, plastics, heavy metals, and high levels of ammonia that contaminate canals. In addition to the heavily polluted waters, the governmental introduction of invasive species like carp and tilapia into the area has negatively impacted the axolotl population. Carp and tilapia prey on young axolotls, making it difficult for the endangered amphibians to add to their numbers.
While tens of thousands of axolotls can be found in home aquariums and research labs around the world, nearly all of these specimens stem from the 34 axolotls that had been shipped to Paris in 1863. This is a big problem for biologists, as inbreeding has made the captive populations vulnerable to disease. And the diminishing population of wild axolotls means the loss of genetic diversity that they so desperately need.
Yesel Kang For The Teen Times
1. What kind of species is the axolotl?
2. What is the most intriguing trait of axolotls?
3. In addition to the heavily polluted waters, what has negatively impacted the axolotl population?
1. Can you summarize the article?
2. Do you know any other characteristics of axolotls?
3. Can you name a few other animals that are on the brink of annihilation?
4. Do you know any other animals that have regenerative ability?