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Axolotls in Peril

Axolotls are everywhere, from pop culture to pet stores and science labs. But in the wild, they're almost extinct

AS YOU READ, THINK ABOUT why it might be important to protect animals from going extinct in the wild, even if many live in captivity.

An Axolotl underwater surrounded by three different axolotl cartoon characters

NATURE PRODUCTION/NATUREPL.COM (AXOLOTL); MOJANG STUDIOS (MINECRAFT); NINTENDO (WOOPER); EPIC GAMES (FORTNITE)

GAME CHARACTERS: Axolotls often appear in video games, including Minecraft, Pokémon, and Fortnite (from left to right).

There's a good chance you’ve come across this internetfamous animal while browsing social media. It’s a frilly salamander called an axolotl (AK-suh-lah-tuhl) that some say resembles a reallife Pokémon. On TikTok, videos of people showing off their pet axolotls have racked up billions of views. Axolotl characters even make appearances in video games like Minecraft and Fortnite. What’s behind this unusual animal’s popularity? “Axolotls are really cute,” says Jessica Whited, a molecular biologist at Harvard University in Massachusetts. “They seem to always have a smile on their face.”

Axolotls have such cute features because they are neotenic. As they age and get bigger, they retain characteristics of their juvenile form (see Life of an Axolotl). “Axolotls are like Peter Pan!” says Diana Laura Vázquez Mendoza, a graduate student studying ecology at the Universidad Nacional Autónoma de México (UNAM). They never seem to grow up. “Despite being an adult, the axolotl never stops looking like a tadpole.”

But the axolotl is more than just adorable. It also has an incredible skill: This animal can regenerate, or regrow, its limbs, tail, spinal cord, and even parts of its heart! To learn more about this ability, scientists are raising and studying hundreds of thousands of axolotls in laboratories around the world (see Laboratory Animal). Yet despite their popularity and importance to science, axolotls are almost completely extinct in the wild. Due to issues like habitat loss and pollution, this smiley salamander is currently one of the rarest wild animals on the planet.

Two men standing up on a boat

LUIS BARRON/EYEPIX GROUP/SHUTTERSTOCK 

THE LAST REFUGE: Ecologists boat through the canals of Xochimilco, the last remaining habitat of wild axolotls.

ICONIC ANIMAL

Axolotls are native to a small region in central Mexico (see Valley of Mexico: Then and Now). Hundreds of years ago, the salamanders could be found throughout the network of lakes and wetlands that spanned the area. It was the perfect place for these amphibiansanimals like frogs, toads, and salamanders that need a moist environment to live.

The ancient AztecsIndigenous people who once lived in the regionbuilt their civilization around the lakes in the valley. The Aztecs grew food on floating gardens called chinampas, which are made from woven rafts anchored in shallow water. Their civilization thrived alongside axolotls. The axolotl became an important symbol in Indigenous Mexican mythology. The creature was thought to be the living representation of the god Xolotl. In the Indigenous language of Nahuatl, axolotl meanswater monster.” The Aztecs also used axolotls for food and medicine. “Axolotls are an icon for Mexican people,” says Mendoza. “We can see our country’s history through the history of axolotls.”

In the early 1500s, Spain invaded what is now Mexico and colonized Indigenous land including the Valley of Mexico. The area’s entire ecosystem—the community of organisms interacting with each other and their physical surroundings—changed. Many lakes were drained to build cities and control flooding. Others dried up because of climate change. That greatly reduced the axolotls’ habitat.

Today, wild axolotls are found only in the narrow canals and waterways of Xochimilco (soh-cheeMEEL-koh), a district of Mexico City. These waterways are what remains of the ancient lakes that once spanned the Valley of Mexico.

In Xochimilco, farmers still use the chinampa system to produce vegetables and flowers for Mexico City, says Mendoza. Unfortunately, the region suffers from pollution, urbanization, and the introduction of invasive species, like carp and tilapia. These fish eat young axolotls and compete with larger, mature axolotls for food.

A HUGE LOSS

In 1998, scientists estimated that there were about 6,000 axolotls per square kilometer (15,500 per square mile) in Xochimilco. Two decades later, their population had dropped to fewer than 36 axolotls per sq. km (93 per sq. mi). Scientists now estimate that between 50 and 1,000 individuals remain in their natural habitat.

Today, far more axolotls— roughly 1 million of them—can be found in aquariums in homes and laboratories than in the wild. Nearly all axolotls in captivity are descended from a small population collected by a scientific expedition in the 1860s and taken to a zoo in Paris, France. There, the captive axolotls reproduced and eventually developed a mutation, or change, to their genetic code. It caused the animals to have little or no coloring in their skin, producing the pink and white axolotls most people are familiar with. In the wild, axolotls are brown or black. 

Street art in a city of an axolotl

LUIS ANTONIO ROJAS/PANOS PICTURES

CULTURAL SYMBOL: A mural of an axolotl in Xochimilco

Unfortunately, “having axolotls in fish tanks does not lead to the survival of wild axolotls,” says Mendoza. And that’s a big problem. Axolotls are a key component of Xochimilco’s food web, or interconnected food chains of what eats what within an ecosystem. Their numbers also help scientists track the health of the waterways in Mexico City: If axolotls are having trouble surviving, that means the entire ecosystem is unhealthy.

The extinction of wild axolotls would also negatively affect medical research. “Losing the ability to study any animal in its wild habitat is a huge loss,” says Whited, the molecular biologist from Harvard. Studying axolotls in their natural habitat helps scientists understand how and why the animals evolved, or changed over time, to develop the ability to regenerate lost body parts.

SAVING THE SALAMANDER

To protect wild axolotl populations in Xochimilco, scientists at UNAM have teamed up with local chinamperos, or farmers who grow crops on chinampas. They launched an ongoing project that aims to unite ancestral farming practices with axolotl conservation.

At the end of canals between the floating gardens, researchers have installed mesh gates to keep invasive species out and increase the rare salamanders’ chance of survival. These gates also contain aquatic vegetation that helps filter and clean contaminated water. Many chinamperos have even agreed to stop using pesticides that can pollute the water

Ecologists creating an ideal habitat for the axolotls

LUIS ANTONIO ROJAS/PANOS PICTURES

1. HEALTHIER HABITAT: Carlos Uriel Sumano Arias, a scientist at UNAM, checks the clarity of the water from a canal in Xochimilco in November 2021.

2. FLOATING GARDENS: Scientists are encouraging chinampa farmers to use fewer chemicals and adopt natural fertilizers to grow their crops.

3. WASTE IN THE WATERWAY: Pesticides from the floating gardens can drain into the canals and pollute the ecosystem.

The chinamperos and researchers at UNAM want to create an environment where wild axolotl populations can once again grow and thrive. When conditions are suitable, the scientists also plan to reintroduce axolotls raised in captivity to the area, says Mendoza. The project benefits both the people and the ecosystem of Xochimilco, all while working to revive the wild population of a creature that is beloved the world over.

PLANNING INVESTIGATIONS: Identify a species in your community that is in danger of extinction and design a project to help protect it

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