Naked Mole-Rats

Alex Re: [00:00:00] Hello, welcome to On Wildlife. I'm your host, Alex Re. On this podcast, we bring the wild to you. We take you on a journey into the life of a different animal every month, and I guarantee you you're gonna come out of here knowing more about your favorite animal than you did before. In this episode, we're talking about one of the most unique mammals in the world.

Everything about these guys is pretty amazing, from their social structure to their wrinkly skin. So get ready because it's gonna get a little dark as we head underground to talk about naked mole rats.

The naked mole rat is a small rodent native to Eastern Africa. Some countries that they may be found in are Kenya, Somalia, and Ethiopia. [00:01:00] Their name is a little bit misleading because their closest relatives aren't moles or rats. They're most closely related to guinea pigs, porcupines, and chinchillas.

Moles aren't even rodents, so they're not closely related at all. The naked mole rat's scientific name is Heterocephalus glaber. In Latin, glaber means hairless, which describes what these animals might look like at first glance. They have pink, wrinkly skin, huge front teeth, and very small eyes. And although they don't have as much hair as most other terrestrial mammals, they aren't completely hairless.

They have whiskers, small amounts of hair on their bodies and tails, and hair between their toes. All of these traits that I mentioned may make them look a little weird, but they're actually all physical adaptations to their environment. We'll talk about the purpose of these adaptations later on in the episode.

Naked mole rats [00:02:00] live pretty much their entire lives underground, rarely coming up to the surface. And because they have minimal hair, they're unable to regulate their own body temperature. They're one of the only mammals that isn't able to do this. Because of this, they need to live in climates that are dry and hot.

They're also very small animals, growing only to about three inches long and weighing just over an ounce. That means they weigh only slightly more than a pencil. And naked mole rats are actually some of the longest-lived rodents in the world, with some individuals living for over 30 years. Now that you have a little background on naked mole rats, we'll take a quick break, and when we get back, we'll talk about what they eat.

This week, I want to give a [00:03:00] shout-out to Zosia from Poland, who suggested that I do an episode on naked mole-rats. Thanks for the suggestion, Zosia. Now back to the episode. Naked mole-rats are herbivores, so they only eat plant material. But because they live underground, they're not eating leaves or fruits.

They eat the roots of plants and also tubers, which are basically enlarged roots that help plants store energy. Potatoes are classified as tubers. They use their large front teeth, called incisors, to break down their food, and like all rodents, the naked mole-rat's teeth never stop growing. So chewing on tough foods actually helps to keep them at a healthy length.

And when their incisors scrape against each other, they actually sharpen themselves. Their front teeth can also move independently of one another. Roots don't have a lot of nutritional value, and they're hard to digest. Because of this, [00:04:00] naked mole-rats have evolved to have specialized bacteria in their guts to help them with the digestion process, and they also do something that we might view as gross and unsanitary.

They eat their own feces. This allows them to really get as many nutrients as possible from the food that they eat. Interestingly, they don't ever drink water. They get all of their water from their food Underground, there isn't a lot of light, so eyesight is not one of the main senses that are used by naked mole rats.

Their eyes are so small that they're pretty much blind. Instead, they heavily rely on their sense of touch. Their whiskers and small amount of hair that they have act as sensory structures to help them feel their way through the environment. In the animal kingdom, it's pretty common to have hair and whiskers that can provide a sense of touch, but what's out of the ordinary is that a large part of the [00:05:00] sensory section of the naked mole rat's brain is dedicated to their teeth.

We don't have all the answers for why that's the case, but researchers believe that their teeth are another important tool for feeling around their environment. Some people even hypothesize that they use their teeth to communicate with each other by feeling the vibrations against the walls of their burrows, but this hasn't been proven.

We do know that aside from eating, naked mole rats use their teeth to help them dig their burrows and to move things out of their way. Another physical characteristic that helps them dig is the hair between their toes. This hair helps them move dirt out of their way like a broom. And they also have loose, wrinkly skin because it reduces their chances of getting cuts and abrasions when they dig through the dirt.

So let's talk more about the burrows that they spend the majority of their lives in. Naked mole rat burrows can span almost two miles long, which is about the length [00:06:00] of 30 soccer fields. They can also be over six feet deep, and when you're that far underground, there's a lot less oxygen available than there is on the surface.

Naked mole rats are able to survive in areas with low oxygen levels that would most likely kill us. They're even able to last 18 minutes without any oxygen at all. In order to make energy, our bodies use glucose, which is sugar, and oxygen. If we don't get this constant influx of oxygen, our vital organs and brain shut down and get damaged.

But naked mole rats are able to use a different sugar called fructose to produce energy in their bodies without the need for oxygen. Pretty cool stuff. Naked mole-rat burrows consist of chambers and tunnels connecting to the chambers. Some of the chambers act as their bathrooms, others are places where they store food, and there's also a nesting [00:07:00] chamber.

And one naked mole-rat isn't living in a burrow all by itself. There can be up to 300 individuals living in a single colony. And they have an extremely interesting social structure because they're one of the only eusocial mammals. Eusocial means that individuals have different roles throughout the colony, and not all of the individuals are able to reproduce.

You mostly see this type of social structure in insects like ants and bees, but very rarely with mammals. So in a colony of naked mole-rats, there's one queen who is the only female that reproduces. If the queen dies, then the three most dominant females will fight each other to the death to determine who will be the next queen.

And the social hierarchy is based on the size of the individual. The larger the individual is, the better share of resources they get, and the larger males get to reproduce with the queen. [00:08:00] In order to assert dominance, larger individuals will shove smaller ones, and if two naked mole-rats meet inside a tunnel, the larger of the two will walk on top of the smaller one to pass by them.

The different jobs that naked mole-rats perform around the colony are also based on their size. The younger and smaller individuals are in charge of keeping the burrow clean and transporting food throughout. Whereas the larger, older individuals usually have the job of defending the colony against predators and intruders.

They may be small, but their sharp teeth can definitely be enough to make a predator stay away. Okay, we're going to take our last break. We'll be right back to talk more about these amazing animals.

Remember, if you enjoy listening to On Wildlife, [00:09:00] you can support us at patreon.com/onwildlife. For just $3 a month, you gain access to exclusive content, early episode releases, and more. That's patreon.com/onwildlife. Now back to the episode. When digging tunnels, naked mole rats will create an assembly line to push dirt out of the burrow.

They're most likely to dig right after it rains because the soil is softer. Then they close the opening of the tunnel so that predators can't get in. Their biggest predators are snakes because they're able to squeeze themselves through the tunnels that naked mole rats make. And one way they communicate with each other is through vocalizations.

Studies suggest that they can produce at least 18 different vocalizations that mean different things to their colony members, such as warning calls, asserting dominance, indicating that they found a new food source, and more. Each colony even has its own [00:10:00] unique dialect. This is one way that they're able to tell their own colony members apart from members of another colony.

Some naked mole rat colonies are right next to each other, which means that members of different colonies can interact, so it's important for them to be able to tell each other apart. Another way that they can do this is through scent. Members of the colony will roll around in the toilet chamber of their burrow so that they'll smell like all the other individuals of the colony.

As I mentioned before, there's only one female in the entire colony that produces all the offspring, the queen. Only about three males in the colony get the chance to mate with her, and she can give birth to almost 30 young at a time. And in order to do so, her body actually goes through physical changes.

The queen's spine increases in length when she becomes pregnant. She nurses [00:11:00] the offspring for about two weeks before they're ready to eat real food. And the entire colony helps to care for the young, but this is mainly the job of the younger individuals. They'll clean the young and also keep them warm by huddling together.

Because of their burrowing habits, naked mole rats are important to the ecosystems that they live in. The fact that they dig tunnels in the ground by pushing dirt out of the burrows means that they're aerating the soil. This is beneficial for plants because it cycles nutrients and gases through the soil and makes it easier for water to be absorbed by the soil instead of pooling at the surface.

Naked mole-rats are also a prey species for snakes, as I mentioned earlier, as well as some birds of prey. Naked mole-rats are important for humans, too. Because of all their amazing traits and adaptations that we discussed in this episode, they're the subject of a lot of medical studies. [00:12:00] What's really interesting is that they're remarkably resistant to cancer.

They can still get it, but at much lower rates than other animals. Cancer occurs when your cells start dividing uncontrollably, and researchers believe one of the reasons that they're resistant to this is because they have a gene that stops this overproduction of cells. By studying naked mole-rats, scientists are hoping to learn more about how this works and how we can use this knowledge to help treat and prevent cancer in humans.

Unfortunately, this research can cause its own problems for naked mole-rats. Ethical issues arise when we think about if we should be using them for these studies. On one hand, it helps the advancement of human medicine, which is really important, but naked mole-rats are living creatures as well that deserve to be treated humanely.

If you want to support organizations that fight for the well-being of animals in scientific research, you should check out the [00:13:00] Scientists' Centre for Animal Welfare. And luckily, naked mole-rat populations are doing okay, especially because a lot of the areas that they inhabit are protected lands. But if you want to support organizations that help wildlife in Africa as a whole, you should check out the African Wildlife Foundation and Sheldrick Wildlife Trust.

Thank you so much for coming on this adventure with me as we explored the world of naked mole-rats. You can find the sources that we used for this podcast and links to organizations that we referenced at onwildlife.org. You could also email us with any questions at onwildlife.podcast@gmail.com, and you could follow us on Instagram at on_wildlife or on TikTok at onwildlife.

And don't forget to tune in next month for another awesome episode. And that's On [00:14:00] Wildlife.