The Naked Mole Rat Could One Day Save Your Life

The naked mole rat’s teeth are situated outside of its lips, preventing the critter from eating dirt. Which is quite lucky—I’ve eaten dirt before. It’s nothing to write home about.

“Sic semper tyrannis,” Brutus supposedly yelled as he helped assassinate Julius Caesar: Thus always to tyrants. John Wilkes Booth exclaimed the same to the panicked crowd in Ford’s Theater after he shot Lincoln. And in dark underground burrows in east Africa, I’m willing to bet the homely yet somehow charming naked mole rat is yelling the exact same thing. Only in a much squeakier voice and not in Latin, I’d assume.

You see, this nearly hairless critter, which is indeed a rodent but not technically a rat, is one of only two mammals on Earth that live in what are known as eusocial societies—think bee and ant colonies ruled by a queen, with multitudes of workers underneath. But instead of being born into royalty, female naked mole rats fight to the death to take the throne, using their enormous chompers to puncture the lungs and other vital organs of their foes.

For a queen, it’s an existence fraught with hazard. But for all of her subjects, there’s little to worry about. They live their entire lives underground, well beyond reach of predators. As such, their lifespans are ridiculously long for so tiny a creature: up to 30 years (if that doesn’t sound high to you, consider that British men in the Middle Ages had the same life expectancy, and probably did the same amount of toiling in mud). Oh, and it doesn’t hurt that they never get cancer. And that nice little trick, ladies and gentlemen, could one day teach us how to eradicate the disease from our own bodies.

Biologist Vera Gorbunova studies these creatures at the University of Rochester. She says naked mole rat societies, which can reach 300 individuals, are more like dictatorships than monarchies because anyone with the gumption can ascend the throne, even if she doesn’t have a fancy III or IV after her name. Any female can, in theory, depose the queen, and males can rise up to become one of just two or three allowed to breed with her. Most females are perfectly happy not ovulating, “but occasionally,” Gorbunova says, “especially if the queen is getting weak, either from a disease or for example she’s just given birth—then another female may start ovulating all of a sudden.”

A good look at the many fine hairs that the naked mole rat uses to feel its way around its burrow. It’s hard to tell if this is a live or taxidermy specimen, which says a lot about the naked mole rat.

The ovulating challenger sometimes will even conspire with a male to murder the queen and take the throne together (I feel like this came up in Game of Thrones, but I can’t for the life of me remember which of the 4,583 characters it could have been). Once she’s in power, the new queen’s body will begin to elongate as the spaces between her vertebrae expand (also from Game of Thrones?), and from here on out she’ll use brute force to maintain order in the colony. It sounds like a crummy state of affairs, but the dictatorship is so tight that peace usually reigns supreme. “So the colony for the most part is very peaceful,” said Gorbunova. “But when there is this social unrest, then they fight, and they fight for life or death.”

Death matches and punctured lungs aside, Gorbunova insists naked mole rats are quite pleasant toward the humans in her lab, unlike typical lab rats, which “bite viciously when they’re upset.” But in the wild, naked mole rats from other colonies are less than welcome—to say the least. Just like in ant societies, each colony has soldiers that aggressively defend entrances to the burrow, snapping and maiming with their huge incisors.

Sometimes, though, they’ll make an exception for a certain kind of intruder: the disperser male. It’s pretty rare, but from time to time a male in a colony will start packing on fat, then up and wander out of the borrow in search of another colony. If he finds one that accepts him, he’ll usually become a breeder there. Scientists don’t understand the hormonal changes that trigger a male to leave, or why this makes evolutionary sense. The odds of surviving above ground are, after all, quite slim for a nearly blind creature with almost no fur to protect it from the elements, or the sharp teeth of predators for that matter.

But more often than not, naked mole rats are perfectly content in their societies, continuously digging out their burrows with those marvelous teeth, which actually grow outside their mouths, saving them the trouble of mouthfuls of dirt. With these they’ll also attack their favorite food, tubers, and the occasional insect larva, not to mention the inevitable intruder. And to keep from accidentally assaulting friends, they identify each other by smell—indeed, they hardly use their eyes at all. Over evolutionary time their peepers have grown nearly useless, only capable of detecting light and dark without any detail, so instead the animals make sense of their surroundings with fine hairs all over their bodies that act like whiskers.

The Nudie Medical Miracle

For all their eusocial weirdness (it’s seriously weird for a mammal, but equally weird for the ornery pistol shrimp, the only marine animal that forms such societies), naked mole rats belong to another extremely exclusive club in nature: Like the remarkable salamander known as the axolotl, they don’t develop cancer. Even if you pump them with carcinogens, nothing happens. Their secret, Gorbunova has found, is a starch called hyaluronan. Engineer a naked mole rat’s cells to stop producing this compound and suddenly a cancer-free critter is capable of developing tumors.

Naked mole rats sleeping, photographed with a nice soap opera filter.

Now, we have the same stuff in our bodies—it forms the extracellular matrix, a kind of scaffolding where cells live—except hyaluronan molecules in naked mole rats are 10 times longer than ours. And strangely, these vastly different lengths convey opposite traits. Whereas short hyaluronan molecules tell cells to divide, while also promoting inflammation, the longer molecules in the naked mole rat have anti-inflammatory properties and, importantly for cancer research, keep cells from dividing too much. Cancer is, after all, the runaway division of cells as they stop properly communicating with their neighbors.

But why would this evolve in the first place? It’s entirely uncommon in the rest of the animal kingdom. So what makes the naked mole rat different?

The answer could be its stretchy, pale, flabby skin—and another burrowing mammal called the blind mole rat (which, by the way, has found its eyes to be so useless that they’re now completely covered over with skin and fur). Despite their names, these creatures are unrelated, but blind mole rats also are long-lived, call the underground their home, and don’t get cancer. “And when we took their cells they also make very long molecules of hyaluronan,” said Gorbunova. “So how come these species are not related at all, but they independently both evolved this unusual molecule?”

Blind mole rats have lost their eyes entirely, and therefore never need to worry about getting red eyes in photographs like this one.

Hyaluronan gives both species their stretchy skin, which Gorbunova reckons allows them to better squeeze through their burrows. “But we’re now looking at more species that are subterranean to prove that for these animals, first they needed hyaluronan to squeeze through the tunnels because their skin is rubbing underground all the time,” she said. “And then it was co-opted for other useful purposes”—that is, keeping the animals cancer-free.

And that is very interesting indeed to cancer researchers. There is still much work to be done on understanding hyaluronan, not to mention figuring out how to develop drugs to exploit it, “but I think there is a very good potential here,” said Gorbunova. “Because if we find a way … to increase levels of hyaluronan in human bodies, we may be able to stop tumors from growing.” Consider families with high hereditary cancer expectancy: Doctors might one day use hyaluronan to stop their tumors from growing in the first place.

Read more at Wired Science