When the Aztecs settled the Valley of Mexico around Mexico City in the 13th century, they found a large salamander in the lake surrounding the island where they built their capital. They called the salamander Xolotl, after the god of fire and lightning. Xolotl was said to have changed into a salamander to avoid being sacrificed so the sun and moon could move in the sky, according to Aztec mythology.
Axolotls are still eaten in Mexico, despite being killed for food by the Aztecs. Axolotls have become one of the world's most famous salamanders, whether as pets or characters in popular online games, thanks to their charisma and easy care. The ability of the creatures to regenerate body parts has made them an interesting study subject. The salamanders are considered to be critically extinct in Mexico.
The Ambystoma mexicanum is a single living genera of the family Ambystomatidae. According to the University of California, Berkeley, there are more than 30 salamander species in the Ambystoma genus.
Some axolotls can grow to more than 30 cm in length, while others can grow to less than 20 cm. The salamanders in captivity live an average of 5 to 6 years, but some have lived for up to 17 years according to the University ofLiverpool.
The canals leading to Mexico City and the remnants of Lake Xochimilco are home to wild axolotls. One of Mexico City's five great lakes was once home to the ancient Aztecs. The lakes were drained in the 1970s to prevent flooding and allow for urban expansion.
They were at the top of the food chain because of their diet. They eat arthropods like insects and spiders. They eat each other. In the 1970s and 1980s, the United Nations Food and Agricultural Organization introduced fish to the salamanders in order to provide more food for local people. The fish are a threat to the salamanders.
Axolotl reproduction begins with dancing. salamanders step in a circle after a male and female stroke one another's uterus, according to the University of Michigan's Animal Diversity Web. The male seductively shimmyed his tail to lure the female to follow. As the two dance partners step together, the male drops a small white capsule full of sperm. The male moves forward until the female just skirts over the spermatophore and picks it up with her cloaca.
During March and June, axolotls go through this courting. The female axolotl will attach her eggs to aquatic plants or rocks when she is done dancing. The young fend for themselves after the eggs hatch. Axolotls take about a year to become sexually mature.
One of the salamander species that never makes it to adulthood is the axolotls. American evolutionary biologist Stephen Jay Gould described the adult salamanders as sexually mature tadpoles because they retain their juvenile characteristics: a fully aquatic lifestyle, a finned tail, and frilly gills. paedomorphosis, or neoteny, is an evolutionary phenomenon of lasting youth. In the journal BioScience, researchers reported that axolotl rarely occurs in the wild and that scientists can force axolotls in the lab to transform.
The obligate trait of axolotls is considered a major force of evolution by biologists and could drive the rapid development of new species. A study published in the journal PNAS found that some genes from axolotls and their relatives are almost indistinguishable. The various salamander species have interbred throughout their history, providing new and potentially important context for researchers trying to conserve axolotls and their relative, and implying that scientists could look to related but less-endangered salamander species.
The International Union for the Preservation of Nature and Natural Resources considers axolotls to be critically threatened. In 1998 and 2008 the population density was found to be 100 individuals per square kilometer. A survey in 2015 found 35 individuals per square kilometer.
Pollution is detrimental to the species. Mexico City has poor waste regulations and high levels of ammonia spilled from waste-treatment plants that cause the canals where salamanders live to be polluted.
In coordination with the Mexican government, scientists, farmers and nonprofit organizations are working to restore the axolotl's habitat by using floating islands of water plants, logs and mud to filter the polluted water. Tourists can see salamanders in their natural habitats with the proceeds going toward the preservation of the environment.
There is a large axolotl population in research labs around the world, but 34 of them were shipped to Paris from Xochimilco, Mexico in 1863. High rates of inbreeding are a major problem for forming a healthy and sustainable population.
The axolotl has a trademark ability to regrowth almost any body part: feet, legs, tails, and even bits of the heart and brain. Scientists reported in the journal eLife that the salamander can mobilize stem cells to repair an injured spine. Axolotls do not stop with the regeneration of their own body parts. All sorts of organs, including eyes, can betransplanted between axolotls without the recipient body rejecting them. In 1968, researchers showed that they could transplant the head of one axolotl to another axolotl. Axolotls are attractive model organisms for scientists.
The ability to regenerate limbs and organs has contributed to a lot of research. White blood cells called macrophages are essential for axolotls. The salamanders just form a scar at the injury site if the cells are not there. The salamander's macrophages are not from bone marrow, as was previously reported, but from the liver, according to researchers in the journal Frontiers in Cell and Developmental Biology. While tissue and organ regeneration in humans is more complicated than in a salamander, the finding provides researchers with a new and somewhat unexpected place to look in humans for potential regeneration therapies.
The genome of axolotls is enormous. The axolotl genome is about 10 times larger than the human one and is the largest animal genome to date. The 32 billion base pairs were put in the order they were found on the salamander. The cell cycle that produces new cells takes 3 to 4 times longer than the typical 24 hours in most vertebrates, according to a report in PNAS. The length of the genes responsible for making aProtein in the body can be 100 to 1000 times longer than in humans. Researchers are still analyzing the data from the genome to uncover the secrets behind the axolotl's regeneration abilities, and to see if genetic machinery could ever be activated in humans to do the same.
Live Science contributor Jeremy Rehm updated the article on May 24, 2022.
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