The naked mole rat queen is dead, long live the naked mole rat queen. On Tuesday, DCist reported that a long political drama at the Smithsonian National Zoo had finally come to a close: its naked mole rat colony has settled on a new queen. And long may she reign.
Here are a few shocking facts about the species to celebrate her auspicious (and vicious) ascent to the throne:
Naked mole rats (Heterocephalus glaber) are what scientists call eusocial animals: adults live in groups and care for their young cooperatively, and only certain individuals get the privilege of producing those young. Ants and bees are more famous examples—the behavior is mostly seen among insects. There are only two mammalian species considered truly eusocial, and both are species of mole rat.
So, yes: queen-bee-style, the most dominant mole rat ladies fight off competitors for the right to bear their colony’s young (while everyone else does the actual child-rearing) by, well, breeding as fast as possible. At the National Zoo, this struggle brought the adult brood down from 17 to 13 over the course of a few months.
"Yeah, they've been fighting and killing each other," zookeeper Kenton Kearns told DCist. "They have mole-rat wars to determine who's going to be the queen or who's going to breed with the queen. We're hoping things will calm down a little bit now."
It’s not surprising that this lady came out on top: she weighs 81 grams, and her second-closest competitor is just 55 grams. Her first litter included three pups, but she’s going to get pregnant again quickly—and as progressive pregnancies stretch out her spine (gross) she’ll grow to carry much larger broods.
The mechanism behind this isn't quite understood, but scientists have found that non-breeding females in a colony are actually infertile, with sexual organs that appear pre-pubescent. As soon as one of these ladies is shipped out on her own, she has a growth spurt and shows the signs of sexual maturity—as she perhaps prepares to stake her own claim as a baby-making queen.
Figuratively (see above) and literally: they’re the only mammals whose bodies can’t regulate a steady internal temperature. Their temperature regulation has a lot more in common with cold-blooded animals like reptiles than it does with other rodents. That’s why you’ll see them squirming around in big, squishy, pasty piles: when they’re not killing each other for the throne, they do a lot of snuggling to stay warm.
In a study published last year, scientists showed that naked mole rats can survive oxygen levels that “would be fatal to humans, and fatal to laboratory mice, and probably to everybody else.” At 5 percent oxygen—less than the atmosphere at the top of Mount Everest—researchers expected their squirmy subjects to display signs of distress within 15 minutes. But an hour later, they were fine.
"After five hours, we were convinced that five percent oxygen is not a problem for these guys, so we decided to call it a night, go home, and have dinner," Thomas Park of the University of Illinois, Chicago told PopSci in 2017. After five minutes in a container with zero oxygen, the animals passed out—but were back to normal a few seconds after release.
One thing to consider before taking a shot at the crown for yourself: naked mole rats don't seem to experience pain in the way we know it. The animals don't react to acid burns on their skin, and they don't treat an injured area as if it's sensitive to heat or touch. Their pain receptors are basically the least sensitive of any mammals studied, which means they can take quite a few punches before their bodies start noticing they're hurt.
Sorry.
For starters, naked mole rats are remarkably impervious to cancer: only a few individuals out of hundreds studied have ever developed the disease. And one recent study found that the bald rodents' risk of death isn't necessarily proportionate to age; in other words, they don't necessarily have a point at which their bodies universally wear out and die. Naked mole rats appear to have some cellular tricks that help prevent aging, and scientists funded by the likes of Google are hard at work on cracking that code.
They actually munch on big-ol’ tubers they encounter while digging tunnels in their underground burrows.
Naked mole rats are known to scarf down feces to get any nutrients left to glean. Recent research suggests the queen's poop might serve a greater purpose: It's possible she feeds it to her workers in order to pass along the pregnancy hormones that predispose a new mother to care for her young. Since naked mole rat mamas don't bother with babysitting their own offspring, they rely on others in the colony to protect the pups as if they were mothers themselves—and they do. It's possible the poop provides a hormonal trigger. So if you find yourself in the midst of a naked mole rat coup, know this: if you lose, you're going to get a lot of crap for it later.
