Giant River Otter: South America’s “River Wolf”

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Speaker 1: Hi, I'm Abdy Money and I'm Rich Schwartz. Welcome to Amazing Wildlife, where we explore 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, in international nonprofit conservation organization which oversees the San Diego Zoo and San Diego Zoo Safari Park. This next species has webbed feet, water repellent fur, and lives in the rivers and creeks in the Amazon. I'm talking about the world's longest otter, the giant river otter. We'll find out what makes them unique and uncover their important role in the Amazon ecosystem. We'll also speak to San Diego Zoo Wildlife Alliance scientists dr Addie Barkos about his five years study of giant river otters and the depths of the Peruvian am is on Rick right away, I recognize differences between the look of giant river otters and other possibly more familiar otter species like the sea otter and North American river otters. I guess the most obvious difference is the large size. How would you describe the giant river otters size in comparison to other otters. Well, you're you're absolutely right with that observation, ebony, you know, inch for inch and pound for pound. The giant river rotter of South America has definitely earned the name giant. I mean, for example, if we compare them to the North American river otter that resides right here in the United States, Well, the North American river rotters average length from nose to tail it is between three and four feet, remember three and four ft. But the giant river rotter, well, they tend to be three and a half feet to six feet in length from nose to tail. Now, get this. The North American river broad er wighs between eleven twenty eight pounds of bending upon the individual and male or female, But the South American giant river rotter weighs between forty and seventy pounds. Oh, and get this, if you wanted to bring a sea otter into the mix, well they're approximately four feet in length and way closer to forty five to sixty five pounds. So even compared to the sea otter, the giant river rotters are pretty big. In fact, they are the world's largest of the thirteen living species of otter, so the name fits. Are there any other notable differences, maybe like behavioral rather than physical. Well, if you're visiting the zoo or an aquarium, or even out exploring the world and you see an otter on the surface floating around belly up casually, using its tail and feet to propel itself, well, that's a sea otter. And if you see an otter swimming mostly submerged, belly down with the top of its head above the water enough to breathe see and hear well, that, my friends, is a river rotter. Despite the differences in the fur and in size and the way in which it swims. Are river otters, like other otters classified as marine mammals Ebony, You might be surprised to hear that although sea otters are considered marine mammals, river otters are not, even though I mean a lot of us think the otter b of course, right, Although there are regions where you can find river otters in seawater, river otters are considered to be semi aquatic mammals. And I know it feels like we're kind of splitting fine hairs here, but let me explain sea otters spend most of their life in the water. In fact, they are even born in the water, no den for them or anything. On occasion, they will spend a little bit of time on land, but by far the majority of their time is spent in the water. Even when they sleep, they just float on their back sleeping. It's pretty impressive. But when we look at the river otter, well, they spend more of their time on land and usually only get into the water to hunt for their prey or their food. Now they'll sleep on land, they have a den. On land, they'll give birth to their young and those are called pups by the way, and they raise them in a den, so the majority of their time is actually on land. What other species are they closely related to? Giant river otters, like other otters, are in the scientific family of mostility, or sometimes referred to as the weasel family, But that can be misleading because it's not just weasels in the mostility family. You will also find badgers, wolverines, minks, and ferrets, just to name a few. But keep in mind when we talk about scientific family. Within that family, there can be a fair amount of subfamilies and different genus that species fall into. For example, the North American river otter and the giant river otter. Although both river otters, they are in different genus within the Mostillitae family. Giant river otters are described as social and some of the other species that you mentioned um, such as weasels, are also considered social species. But what is that? Does that mean? Many giant river otters are considered to be very social animals. They live in a family group that is usually in the range of anywhere from four to ten individuals, but some family groups can reach up to twenty individuals. Within this family group, there is usually one breeding pair, with other members of the family having other roles in the group. They hunt together, take care of the pups, and maintain the boundaries of their territory together, and these family groups allow young to stay within the family even after new pups are born. Now, this gives support to the breeding adults and more opportunity than for the subadults to grow and learn more before heading out on their own. And because this increases the opportunities of each individual to thrive and survive, this in turn helps the overall population. Rick I read that giant river otters actually hunt and packs and given their description. That sounds very intimidating. How does this work? Well, interestingly enough, Ebony, one of the giant river otters common names is river wolf, and we all know the power of the wolf pack. For giant river otters, although they hunt in water, the power of the pack is no less important when it comes to hunting for food. The majority of the giant river otter's diet is fish and they will work as a pack to chase the fish into the shallow waters, limiting the fish's opportunities to escape the pack. So by working together, it increases the odds of a successful hunt and everybody gets to eat. So, giant river otters, as you mentioned, are carnivorous. What does their diet consist of? What is the pack eating? Yes, and not only are they carnivores, Ebony, they are apex predators, meaning that they are at the top of the food chain when it comes to their prey. They are effective fish hunters. In fact, fish make up the majority of their diet. But to answer your question, they will also hunt snakes, cayman and crabs if fish aren't immediately available. So Rick, I understand they use communal latrines and that's how researchers have determined what they eat. Is that correct? Yeah, And just in case you know, it's not sure, A communal a train basically means the family group that we're talking about, we'll all use the same spot to go to the bathroom. And this can actually be really good for scientists because that allows them to do what we call sort of a sampling of that that waste, if you will, to really look through what has passed through these animals to tell us then what they're eating. It actually can be a lot of really great information about what's going on in the entire environment, because again, these animals are apex predators, meaning they hunt whatever is alive in their environment. So to get a snapshot of what's going on, there might be one portion of the river where one giant river otter family is eating mostly crabs and snakes right now, where further up river they might be eating mostly fish. And this really helps kind of shed some light to the health of the ecosystem. And speaking of shedding some light, I'm starting to realize just the connection between research and waste. It's it's hard to believe that so many species have a special poop story. Yeah, it's true. That there's a lot of information on what comes out that backside of every animal. So so, moving on to the giant river otter young. How many pups do giant river otters have and how do they care for them? Well, Ebony, when it comes to family life, taking care of the babies, the giant otter knows how to do things right. It starts off with the adults building dens in river banks or in the lake shores. And these dens are pretty impressive too. They are's multiple entrances, they have different chambers inside. You know, it's just it's quite elaborate when you think about just this mammal digging into a riverside. Once these dens are established, the females will give birth to one up to five puffs in the den, usually in the window of August and timber. Now males will take a role in raising the young two. You know, as we mentioned earlier, the family group is very important to the species. Now, moving forward a little bit, the pups will leave the den with the parents a few months later, usually October November. And this just so happens to be the dry season when the water levels are usually at their lowest, and that's actually a good thing. So the lower waters force the fish into channels and increases the number of fish found in these areas, making it much easier for the adults to get plenty of fish for the growing family, and it offers up great opportunities for the growing pups to start learning the ins and outs of catching fish. Gotta love a hands on dad, right, Yes, So let's switch gears and touch on the giant river otters impact on biodiversity. What is the giant river otters role in South America's aquatic system. That's a great question because we kind of always want to remind ourselves every animal, from a small bug to a giant riva or plays an important role. And like we mentioned before, ebony, the giant river rotters, well, they're an apex predator and the role of an apex predator in its native habitat is very important. Now, on the surface, we know apex predators hunt the weak and unhealthy, mostly because they're the easiest to catch, but this also keeps the overall population of the prey species healthy. Now, taking it a step further, apex predators tend to keep smaller predators in balance as well. This happens indirectly, as apex predators territorial and hunting behaviors influence the territories and hunting behaviors of smaller predators. And again, like we kind of talked about already, so you ought to know this one. The other importance of the apex predator is that we can study them and what they're eating and how they're behaving to gain a better understanding of how things are going in the overall ecosystem. So, Rick, would being an apex predator be similar, like in Layman's terms, to being like the top of the food chain within the habitat. That is exactly correct. Yeah, because no one really hunts them naturally and that puts them at the top. And also because they hunt multiple species in their region, it really puts them at that very first link, if you will, of the food chain. So, although they're not hunted giant river otters, their populations are decreasing. What's threatening the giant river otter population? Yes, Ebony, Unfortunately, that is correct. The International Union for Conservation of Nature or i u c N does list them as an endangered species, and unfortunately their numbers are decreasing. In fact, they were thought to be extinct in the country of Argentina since the eighties until one was discovered in May of Giant river otters face a wide variety of challenges in the wild, from hunting and trapping to logging and wood harvesting, agriculture, dams being placed in the water for water use management, and get this, even mining. How does mining in the hills above the waterways impact animals that live in the river Well? Unfortunately, mining involves a lot of runoff water that is polluted and that ends up then in the creeks and rivers and lakes. That runoff pollution contains mercury, which once it's in the water, it's consumed by fish and it can even enter their body as water flows over the gills. The mercury is poisonous, but it may not be enough to kill the fish right off. But as you probably recall, giant river otters are apex predators that enjoy a diet made up mostly of fish. Eating fish with mercury places more and more of the mercury into the otters and can make them very sick and even cause them to pass away. The challenges these amazing giant otters face today seem almost impossible to deal with. But like many animals facing challenges in the wild today, most of these challenges are because of human behavior, and honestly, I see that as good news because that means the solutions are within our power to find and create. Way to be positive, that's a lot for otters to overcome, But I see what you mean about the solutions are ours to find because humans are the cause of many of those challenges. And in just a moment, we're going to speak with San Diego Zoo Wildlife Alliance scientists Dr Audi Baricos about his conservation work with the Giant River otter in Peru. But now it's time for the San Diego Zoo Wildlife Alliance minute an opportunity for you to learn what's new at the Zoo. Despite the endangered status of at least one third of all reptiles worldwide, and thus the critical need to preserve their reproductive cells, there's a lack of research in the cryo preservation or freezing of cells and tissues for these species. Developing protocols for endangered reptile sperm cryo preservation is challenging because it can be difficult to obtain sufficient arm samples However, thanks to a long standing partnership with the University of Florida, San Diego Zoo Wildlife Alliances, Reproductive Sciences team has received over forty reptile sperm samples to analyze and develop cryo preservation techniques for many species, including green iguanas, black spiny tailed iguanas, veiled chameleons, Argentine black and white tagus, and Burmese pythons. This represents the first comparative, comprehensive attempts to develop sperm cryo preservation protocols for reptiles and will serve as models for other reptile species in the future. We're continuing our conversation about the Giant river otter. Were now joined by Dr Addie Barcas at post doctoral asset Shate and River Ecology with San Diego Zoo Wildlife Alliance. Welcome to Amazing Wildlife. Hi Bunny, thanks for having me. It's good to be here. So you've been working with the Giant river otter for for years and in the jungles of Peru. Can you explain how that all came about and why this species? So? Yes, we are indeed starting our sixth field season with this project. It was an initiative by San Diego Zoo Wild Lefe Alliance in combination with the wild Care Unity with the University of Oxford. Both the institutions were interested in understanding what threatens giant auters. Wow, so can you describe your your giant river otter research site? So? Giant atters can be found in all kinds of water bodies like swamps and rivers, but what they really like Our oxbow legs oxbule legs are narrow and long bodies of water that have some connection to rivers. In oxbule legs there are predictable amounts of fish and more good places for giant totters to rest and to build their dens. Our study area includes oxbu legs that are protected with limited access to people and oxbu legs that are exposed to human activity like fishing and gold mining. And how do you go about tracking a giant river otter in the Amazon? If you're interested in the behavior of a giant atter group, the best way to study it is to follow the otters on the water with a rubber boat and use a video camera with a strong zoom to record their behavior. If you want to understand demographic processes, which means how many of the otters survive from ear to ear and how stable are the populations. All you have to do is take a picture of the front of their necks. Each giant atter has unique neck marks that are very useful for us because this way we can learn about their life history without having to actually capture and mark the animals. So you've observed a lot of mining inside giant river otter habitat. How does this affect the otters? This is a good news bad news situation. I'll start with the bad news. Fish are less abundant in areas with gold mining, which means there is less food for giant atters. Water in mind Oxbow Leggs has lower quality. Also, much more of the bank habitat is cleared and degraded, which makes it more difficult for otters to build dens and find good resting sites. Now the good news. The good news is that we found giant atter groups in places that we once thought were unfit for them to live, like abandoned mining ponds with murky water, and overall in the gold mining area there are a number of stable family groups. This suggests that if in the future, gold mining stops and we put some effort into the recovery of Amazon freshwater ecosystems, it is very likely the giant tutors will be able to rebound to higher numbers. And this is all possible. Your work and your research is made possible with the help of partners. Can you talk about the collaboration with partners. Yeah, we work with Peruvian authorities like the Forest Service and the local National Park Service, and with several nonprofit organizations, for example the Frankfort Biological Society. The Giant Author Conservation Project also has a team that works with local communities, which has formed strong partnerships with local leaders and school teachers. I want to take this opportunity also to shout out to all of the field assistant and volunteers and drivers and workers that make our project possible. And when you talk about community members and volunteers, how are these community members helping? How, for instance, are our teachers helping. So it's becoming more and more evident for wildlife biologists that conservation projects cannot succeed without the involvement of local populations. Our great Peruvian community team focuses on understanding the awareness of people to the environmental consequences of their activities and their willingness to collaborate for more sustainable practices. More importantly, community team members give workshops in local schools, mediated by the teachers and the Principles, in which they teach the kids about the area's animals and plants and share with them the results of our studies and also some cool giant daughter videos. So how does educating the next generation? How do researchers hope this will help the giant reperator. Well, we hope that consistently and frequently talking to the kids about animals, conservation, the value of fresh water ecosystems will ultimately induce a behavioral change, so people will be more responsible and what they do to the environment. There will be less tendency for deforestation and gold mining and habitat destruction. And we think that the children and young kids are a great gateway to sort of influence the adults. So what's the most amazing thing that you've observed giant river otter is doing. I have a few favorite behaviors. For example, when giant atters catch a fish, they must eat it on the water surface, but they also have to protect it from the other authors, especially cubs trying to snatch it from them. Their mouth is full, so they have to make a sound from the nose and it sounds exactly like Chewbacca. I also really enjoyed seeing giant atters lying in the sun and grooming on logs by the water. They sometimes make otter piles and step on each other to move around. This is also where you learn about the social dynamics of the group. Another co observation. We sometimes get a chance to see these giant tatters families taking cubs for swimming lessons. They carry them in the mouth to open water and get into a really tight formation, so if one adult gets tired then drops the cup, then another one can pick it up and carry it along. The cubs gradually become independent and learn to swim in the water, so they are not born just swimming. They actually have to learn to swim. Yeah, but it's a kind of harsh teaching. They get thrown into the water until they learn to swim. Then another member of the group grabs them, and then when there's no more need to grab them, then it means they know how to swim. So just kind of thrown in there. So what is the giant river utters status in nature. Giant actors are distributed in a number of South American countries and at the moment it's considered endangered. And so because of all the threats that we've mentioned, that because populations are only now maybe reaching the full capacity in some areas, for example the National Park to study the National Park, which is a really strong giant outer population, and so the situation is mixed. So in many areas giant authors are not doing as well as in our protected areas, and that's why for caution, they are still considered endangered. But as I mentioned, there are a few optimistic stories. For example, the first giant aughtors seen in Argentina for a couple of decades that happened a few months ago. Well in there. On that positive note, thanks so much for being with us. We've been speaking to Dr Audi bar coas with the San Diego Zoo Wildlife Alliance. Thank you, Bunny, thanks for listening. We hope you enjoyed learning about the giant River otter and be sure to subscribe and tune into next week's episode, in which we're bringing the story of a unique bear species that actually can make a nest in the trees I'm EPI Money and I'm Rich Schwartz. Thanks for listening. If you would like to find out more about San Diego Zoo Wildlfe Alliance, please visit sdz w A dot org. Amazing Wildlife is a production of I Heart Radio. Our producer is Nikia Swinton and our executive producer is Marcia Topina. Our sound engineer and editor is Amina Gnatra. For more shows from my heart Radio, check out the I Heart Radio app, Apple podcast, or wherever you listen to your favorite shows.