The Current - The fight to save the axolotl, an ever-smiling salamander

Episode Date: May 8, 2025

The axolotl is a salamander that always appears to be smiling, making them popular as aquarium pets or as characters in video games like Minecraft. But the species is endangered in their natural habitat in Mexico, where researchers are working hard to preserve them.

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This is a CBC Podcast. Hello, I'm Matt Galloway and this is The Current Podcast. If you have young children, you've probably heard all about axolotls. The axolotl is an amphibian, very cute looking salamander. It seems to be smiling all the time. For kids, they are popular as stuffed animals. They've also appeared in video games like Minecraft and Fortnite and they are loved as pets in aquariums. But in their natural habitat, in Mexico City, they are endangered. Now, after years of work to

save them, new research is showing that axolotls bred in a lab seem to be thriving when they're released. Luis Zambrano is a senior researcher at the Institute of Biology at Mexico's National Autonomous University. He has been studying axolotls for decades. He's in Sao Paulo, Brazil. Luis, good morning. Hi, nice to meet you. Hi, Matt.

It's great to have you here on the program. I want to talk about the recovery in just a moment, but talk about why the recovery was necessary. What happened to the number of axolotls that lived in the wild over the years? I mean, we have made census or counting of these animals since 1998 and they have become a huge problem in terms of population. I mean, in 1998, there were about 6,000 per square kilometer.

And in the last census we did was in 2014, and it was only 36 per square kilometer. So the depletion has been huge in the last decades. We are doing at this moment a census, and we will show the results in about a couple of months, but they are in real danger. This is a story about development in many ways, right? It's development that has destroyed their habitat? Yeah.

I mean, one of the problems for the axolotls is that the habitat of the axolotls is in the middle of the city, that Mexico City, where we live 22 million people there. So the habitat has been particularly deteriorating in the last, well, in the last two centuries. The world park has been in the last 50 years or something like that. So the population is going down because of the urbanization of the area. And so you and your team bred axolotls in the lab.

Tell me about releasing them into the wild. There were 18 of them that went out into the wild. Yeah, actually, it's not exactly in the wild. It was in a refuge. I mean, when we saw that the population were coming down, then my lab started to create a program called Chinampa Refuge. Chinampa is the islands that are around this habitat

that has been for 1,500 years in Mexico City. So we created this refuge. And part of the experiments we tried to do was, okay, if the habitat is working, if the restoration is working, and we saw that yes. And this second part of the experiment was how do they move, if they can move properly in this refuge or not. And we saw that they can move, they can survive very well in these areas, and they can feed

and they increase the body mass, for example. How did you track them? I mean, once you released them, how did you know where they were? Because we use telemetry. Telemetry is like a chip that we introduce in the animal and then we follow them with antennas and see in which area they normally stay. So, particularly, it's not that we cut them every time but that we see where they are. And then at the end of the experiment we try to retrieve all of them because we know exactly where they are and

we try to use nets and every type of thing to recollect them. I mean, they are very, very difficult to catch. Let me tell you. You did catch them and you were able to see that when they were out there in that refuge, they were thriving, right? The ones that we could catch, I mean, they, yeah, they were larger, fatter, I mean, bulkier, basically.

So we understood that they are quite happy once you relive them in these areas, in this refuge. I mean, there is enough food for them, basically. Were you surprised by that? Oh yeah, I mean, well, it's not like we were surprised in terms of that we didn't expect something like that. But we were quite happy to see that the refuge are working and it's enough food for them. The thing that we were surprised is that they move by far much more than we expected.

When you see those animals in tanks, you don't see them moving too much. But when you release them in the wild, then in this refuge, you can see that they can move 100 meters, 200 meters per day, which is a lot. So every time I see these things, I say, okay, they are quite unhappy in these small times because they could move around all the time. What does that tell you, what you learned about the possibility of ensuring that this species comes back? As you mentioned, the numbers of them have fallen off dramatically.

So does this give you hope that you could restore them to their natural habitat? Yeah, actually part of the things that we are quite happy is that, I mean, the programs that we are creating can work properly once it's inevitable that we have to reintroduce them. Basically, it's a good news that we are going in the good direction in terms of restoration. And the only thing we need now is like the people

and the government to understand that this is the correct path in order to go in that direction for the restoration of the animal in their own system. This is important, I mean, for your work, but it's also important for Mexican culture. I said that for people around the world, they know them as stuffed animals. You said that this is a part of Mexico's identity in many ways. Yeah, actually it's funny, but because everybody started to know about axolotls

in the last 10 years or something like that. But in Mexico, we are part of our culture for 1500 years, was part of Mexican pre-Columbian culture. He was considered the twin brother of the most important god, for example. So since Aztecs and Awats, the people loved this animal and was part of the culture. From then to now, it happens many things. For example, it has been used for food or it has been used for traditional medicine. And in the last 50, 60 years ago, people like painters like Diego Rivera

used to paint these animal in many of the most important murals. What does it mean for Mexican culture beyond the scientific value? What does it mean for the culture to see these coming back? Okay, I think that is our identity. I mean, it's part of, it's like in my ease, or in like the jaguar, that is part of Mexican identity.

When you come to Mexico and see a lot of this nature around us that creates our culture, the axolotl is part of this Mexican culture. You said, I mean, you're talking about Mexico City, which as you said, has 22 million people. It's an enormous urban area. You said, if we can restore this habitat and restore the axolotl's population in the city

of more than 20 million people, I feel we have hope for humanity. What did you mean by that? I mean that if the habitat of Hispanic by far managed and destroyed for 22 million people. And if you have the knowledge and the quality to restore everything, that means that in any place around the world,

the people can join together and start to create restoration programs in any place. That will help us a lot in these environmental crises that we are living at this moment with the climate change for one side, the reduction of the biodiversity in the other side. We face a lot of problems as a humanity in many areas. I mean, and now I am in Sao Paulo, if you see the destruction of the nature around Brazil, it's huge. But if we could restore a very, very bad place for a very important animal for our identity, then we can do it in other places around, I mean, in Africa and in South America, in North America, in Europe. You can do many things on how to create the environment, the

social environment, the economical environment in order to restore that area because it's far more important than other things, such as easy money or the next generation of iPhones, for example. That must be really encouraging. I mean, this is your life's work, and I just wonder, you must feel enormously gratified

in seeing the small step. Yeah, actually we have very good news. And I mean, we seldom have very good news and this is a very, very good news that help us to have a step forward to the restoration. I hope that we need at least 10 or 20 good news like this one in the next five years in order to still having hope and going

in the good direction for the restoration area. So we are quite happy at this moment. Good news is in short supply. I'm glad to talk to you about it. Luis, thank you very much. Thank you. And I mean, and please be in touch with us for the next set of news in the next two or three years. They will be, some of them will be good, maybe some of them will be bad. So yeah, this is a long run. We will be back in touch and we'll get you back on the program with an update. Thank you.

Thank you very much. Luis Zambrano is a senior researcher at the Institute of Biology at Mexico's National Autonomous University.