Chinese Giant Salamander: A Living Fossil

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Speaker 1: Hi, I'm Richwartz and I'm Apanemona A. Welcome to Amazing Wildlife, where we explore the unique stories of wildlife from around the world and uncover fascinating animal facts. This podcast is a production of I Heart Radio and San Diego Zoo Wildlife Alliance, and international nonprofit conservation organization behind the San Diego Zoo and Safari Park. The Chinese giant salamander is the largest living amphibian on the planet, with some reaching nearly six feet in length. They are well camouflaged and the rushing waters of China's Mountain river system, where they were once common but are now critically endangered due to habitat loss and excessive hunting. Rick, we hear about species that are vulnerable and unfortunately about ones that are endangered. But how dire of a situation is it once an animal reaches the status of critically endangered ebony. I'll answer your question just a moment, but first I want to bring our audience up to speed on this amazing amphibian we're talking about in this episode. Like you said, these grayish brown salamanders are capable of reaching six feet in length and weighing as much as a hundred ten pounds. Oh, and get this, they can live upwards of eighty years, with some unofficial reports stating there was one found that was over one hundred years old. We also know from fossil records that this species existed around the same time as dinosaurs, some three hundred fifty million years ago. These are truly fascinating amphibians and I am so glad we're taking the time to talk about them and now to follow up on your question. Unfortunately, Ebany, it is indeed a dire situation when any species reaches the status of critically endangered. The International Union for Conservation of Science or i u c N, states that the critically endangered listing or category contains those species that possess an extremely high risk of extinction as a result of rapid population declines of eighty or more than over the previous ten years or three generations, a current population size of fewer than fifty individuals, or other factors. And it's worth noting that the i UCN red List does not consider a species extinct until extensive targeted surveys have been conducted. Therefore, species that are possibly extinct might still be listed as critically endangered. All the more reason to raise awareness about the Chinese giant salamander. Now, the giant salamander is protected by laws restricting its international trade, yet overharvesting for human consumption is still a major problem. What's being done to help ebany? There are a couple of things going on to help in the conservation of the Chinese giant salamander in China. This species is listed as a class to state major protected wildlife species. It occurs or at least used to occur, in many natural reserves within its range, and some natural reserves even use the species as their main conservation target. There are some under human care for breeding and rearing, and it's believed to have had some success, but these projects are mainly to meet the market demand because, as you mentioned, they are harvested for human consumption. At this time, there isn't enough data to say if the breeding programs have had enough of an impact for the overall population, and it's worth noting China has implemented an educational program to help people understand the needs for conservation of the species, but more time is needed to better understand how successful all of that really is, and the Chinese giant salamander has been resilient over the years. They are considered, in fact, like you mentioned, living fossils, having seen the dinosaurs come and go. Rick, what do scientists mean when they say that the ancestors of the giant salamander diverge from all other amphis me in more than one hundred and seventy million years ago. Well, essentially, Ebany, the Chinese giant salamander. They're one of three known giant types of salamander, all of which diverged from other amphibians during the Jurassic period. The Japanese giant salamander is a bit smaller than its Chinese counterpart, while North America's largest salamander, the hellbender, may reach up to twenty inches or just over two feet in length. With the millions of years that they have been around, it has earned them the nickname of a living fossil. Rick, Can you expand on the differences between the various species of giant salamander? Oh, yes, Ebany. Although we have three officially recognized species alive today, the Chinese giant salamander, the Japanese giant salamander, and the North American hellbender. A study published in the journal current Biology states that scientists trace the genetics of one thousand, one hundred giant salamanders and discovered that they were more evolutionarily distinct than previously thought. The results suggest that there could be at least five distinct species of giant salamanders that developed independently and isolated locations over millions of years. Rick, let's talk more about what makes the Chinese giant salamanders so unique? About some more of its um unique traits. What adaptations allow for it to live entirely underwater? Oh, honestly, many I think the coolest adaptation that they have for life underwater is their skin. Now, it might seem odd to say that, but you have to understand these salamanders live their whole life underwater, and they have no gills. Their skin allows for the transfer of oxygen into the body and the release of carbon dioxide out of the body, making their skin a true respiratory surface, almost like the inside of our lungs. And to help maximize their ability to breathe like this, a conspicuous fold of skin along the salamander's flanks increases the surface area of the skin through which oxygen can be taken. In this is why you will only find them in fast flowing, moderately shallow waters because these waters are well oxygenated due to the tumbling flow of the water. That is so interesting. So we start off the conversation by referencing the giant salamander's impressive ability to camouflage. Can you explain how the amphibian is able to remain relatively undetected and stay so mysterious? Oh? Yes, evany, they are well camouflaged and tend to stay very still, making them so hard to see. They are sort of this modeled grayish or greenish and brown color, with a long, thick body and four stubby limbs. Their heads are blunt, almost shaped like a rounded shovel head, with tiny eyes behind their nostrils. Its long tail makes up over half of its body length as well. All of this to say, it easily blends into the rocks and logs at the bottom of fast moving water where it lives. And I'll share this as well. We have one living at the Wildlife Explorers base camp at to Sandy Go Zoo. I know exactly where it lives, I know its favorite hiding spots, and it's still hard to see sometimes giant salamanders are also known for having poor eyesight. How do they work around this shortcoming? You're right, ebony. Their tiny eyes aren't much help for seeing the world around them, and most likely serve as a way to detect contrasting light and dark areas. So instead of keen eyesight, these giant salamanders detect prey by sensing their vibrations in the water. Sensory nodes run alongside of the Chinese giant salamander's body from head to tail, enabling it to detect prey movement. These sensory nodes are so effective that the salamanders are most active at nighttime because they don't need the light to see their prey. So, speaking of prey, what do Chinese giant salamanders eat? The Chinese giant salamander fills the top predatory niche in the rushing freshwater ecosystems. They will consume fish, frogs, worms, snails, insects, crayfish, crabs, and even small salamanders. Like any top predator of their ecosystem, they help keep other animal populations in balance. This, in turn, keeps the freshwater ecosystem healthy and well. Let's move on to their behavior. The behavior of the Chinese giant salamander. They may not be easily spotted, but are they known for making any sounds, or swimming fast, or exhibiting any other detectable behaviors. Well, Eban, like you mentioned, they are primarily nocturnal and live in fast moving waters. When I first started learning about them, I assumed that they were also very good swimmers. Truth is, they aren't very strong swimmers at all. In fact, more often than not, they don't swim, but rather go with the flow if heading downstream, and if they're heading up stream, they do a slow walk along the bottom of the stream or river, gripping and pushing against rocks with their feet along with thrusting forward with their paddle like tail. And when it comes to vocalizations, well, it isn't very well studied. I looked around quite a bit, and the only documentation I could find that was out there about their ability to vocalize states that they make a call similar to a human baby crying when they're captured. But it's fair to say we don't know enough about their ability to communicate underwater to know if there's other sounds they might be making as well. Yeah, I read that too. That was that was kind of said to read and imagine as well. So what about their family structure, their family life and phibian's um at least the ones we've covered so far. They may not be known for having complex social structures like some other animals. But what can you tell us about the Chinese giant salamanders reproductive practices? Well, for the Chinese giant salamanders, breeding season is usually within July, August and September, when the water temperature warms to about sixty degrees fahrenheit. Males and females do not interact or cohabitate during other times of the year, but during the breeding season they will when the time is right. The female will lay four hundred to five eggs in a string in an underwater bird and usually goes back to her solitary life. The male will fertilize them and protect those eggs for the next one to two months until they hatch. But once they do hatch, they're on their own. The mails will go about their business and the offspring will receive no parental care. So there's not really a lot of social behavior going on, at least not that we know of. Just ahead, we'll talk to Brett Baldwin, an Associate curator of Herpetology and Ichthyology with San Diego Zoo Wildlife Alliance. But first this Now it's time for the San Diego Zoom Minute, an opportunity for you to learn what's new at the Zoo. Now we've been talking about the Chinese giant salamander and spotting this critically endangered species in its native habitat is exceedingly rare, but guests at the San Diego Zoo now have the unique opportunity to take a close look at a sleek and mysterious creature at the newly opened Wildlife Explorers Base Camp Sandy goes To. Wildlife Alliance and conservation partners including Ocean Park Hong Kong, are working toward the goal of creating a breeding group of Chinese giant salamanders. The goal is to eventually re establish depleted populations in the Chinese giant salamanders native range, while at the same time educating the public about the conservation of its habitat in China. Did you know all three types of giant salamander produced a sticky white skin secretion that repels predators except humans. Wild Life Explorer's Base Camp at the San Diego Zoo is one of only six places in the US where guests can experience Chinese giant salamanders. This large amphibian can be seen in the Cool Critters Building and is one of many species in the newly opened immersive environment. Brett Baldwin is the Associate curator of Herpetology and ich Theology with the same A Zoo Wildlife Alliance, and is joining the conversation as we continue to learn about this unique amphibian, the Chinese giant salamander. Hi Bratt, Hey, how are you great? So, as the associate curator of Herpetology, which is the study of reptiles and amphibians, I'm learning and in theology, which is the study of fish, how would you describe your position? So I oversee animal care and husbandry of the said departments. I ensure that the habitats the housing they're in are up to and beyond as a standard with the public views. Is aesthetically pleasing, but yet also making sure that it's best for the animals too, so there's two different aspects of it. I also manage the animal moves and shipments, which we do a lot of here and I oversee a population management of those animals reptiles and amphibians and fish, so the reproduction of all the animals we house and care for at the zoo and the safari park. So with the Chinese giant salamander and amphibians as a whole, they're said to reflect the health of the environment because they absorb the water and oxygen through their skin. What does that mean for you? What does that take um to care for such an animal. So what that means is they're like the canary in the coal mind where they are an indicator of what's going on around you that you might not know because of their physiology, their skin, how they absorb moisture through their skin, their skin is very sensitive, so they are very sensitive to any changes in the environment. So what are some of the major factors contributing to the decline of the Chinese giant salamander? Historically it's been human consumption. They're required from the wild or many many many decades for food medicinal purposes. Pollution has been a contributor and the habitat loss to building up dams, changing waterways that has done a lot to to reduce where they live but the main thing, even recent studies has shown that that it's still people that are collecting them from the wild, because there's a lot of these farms that have been set up over the last couple of decades where they farm these salamanders in large numbers. And speaking of that, um, the diminishing wild population led the Chinese government to encourage farming of the species to satisfy the continued culinary demand for the giant salamander. But I understand that this intended solution has actually caused some other problems. Can you explain. Yes, So, in theory, it sounds like, wow, that's a really good idea bringing these animals and breathe them so that there's these big populations of them. But it's likely that these places are not doing the disease testing frequently and they may be housed in crowded situations. Also, we know that there's three different lineages now of these salamanders as of recent so they could be there's a new species that they've described they know it's genetically different, and then a third one also. So, um, there's this question whether or not it's a good idea to have these animals in these large farms and to actually release them into the wild because again, as I mentioned before, the amphibians are very sensitive to disease, so in a large population, it's very easily for disease to be there. And unless they're doing regular testing and there's veterinary care going on on a regular basis and the DNA the genetics are known, then it creates a different situation. So some salamanders can regenerate a tell or a toe or an entire limb if injured. Is that the case with the Chinese giant salamander? It is. Indeed, there has been a report where an animal had leg missing and then after a year or so it had another leg had regrown it. Yeah, so it's thought that maybe it has something to do with the earlier stages in their life when they're younger, that it's more likely that that occurs as they get older, it may not happen. That superpower phades a bit. So that's pretty cool and hard to beat. But is there any other characteristics that you find to be the most interesting about the giant salamander? The size of it is what really gets me, because we have our native salamanders here in southern California that are three to five inches long, and they look so similar, yet the size difference is just incredible that they're in this very closely related How closely related they are? And how can people better coexist with the Chinese giants element or is there anything that that we could do better? I think that it's really important that people understand how many there used to be where they used to live, and then how it got to the numbers that they are now. That's the big one. Educating the younger people that will be taking care of this situation in the future and making sure that they understand what used to be and how it got there. And what would you say is the best part of your job? What's your favorite part of your position? I work with such a diverse group of animals like lizard, snakes, turtles, frogs, fish, and that's really just a huge bonus. Every day is different. One day I come in and there's a medical procedure that's going on with the giant main Shan mountain viper also from China that's very rare, which we may be doing X rays on it or CT stand on this snake. And then the next day maybe there's a bunch of baby turtles hatching and the incubator that we've been waiting for for three months. And then the following day we're boxing up some crocodiles to chip FedEx to another zoo across the country. So I think that because I get to do something different every day, it's just like that makes it exciting. Thank you to Brett Baldwin, the Associate curator of Herpetology and Ichthyology with San Diego Zoo Wildlife Alliance. Thanks so much, Thank you, thanks for listening. We hope you've enjoyed learning about the Chinese giant salamander. Be sure to subscribe and tune into next week's episode, and which will bring you the story of an animal no one for defying typical biological laws and has become well known thanks to a popular online video game that involves mining and crafting. I'm empty money and I'm Rich Schwartz. Thanks for me. If you would like to find out more about San Diego Zoo Wild Left Alliance, please visit sdz w a dot org. Amazing Wildlife is a production of I Heart Radio. Our producer is Nikkia Swinton and our executive producer is Marcia to Peina. Our audio engineer and editor is Sierra Spreen. For more shows from my Heart Radio, check out the I heart Radio app, Apple podcast, or wherever you listen to your favorite shows.