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The Many Mammal Moles- Part 3

In my series on moles, we have covered a lot of weird, weird animals. What we haven’t covered, however, are any rodents. This is an odd exclusion, as the classic pop-cultural depiction of a mole is clearly a member of that populous family of mammals, what with its oversized buck teeth.

Whack A Mole Inflatable (15 x 15)

While the naked mole-rat is the most famous rodent to live like a mole, there are actually many that take up this subterranean lifestyle, including other mole-rats that aren’t naked. The naked ones are indecent! First up, however, is an entirely different family of burrowing rodents, well-known in their home territory but practically known anywhere else.

Bamboo Rats

Bamboo Rat

Oh god yes, that face. I’m a sucker for any rodent whose teeth take on that orange color, and the way they stick out of that flat little nose is just too delightful. Fun fact, beavers and a few other rodents have orange teeth as well because their tooth enamel includes iron, making it more resistant to the stresses their lifestyles subject their teeth to. In the case of the bamboo rat, these stresses relate to digging, as the rodent uses its teeth to burrow. Living almost entirely underground, bamboo rats, like most subterranean rodents, are herbivorous, feeding mostly on roots and other underground portions of plants, including but not limited to bamboo.

Bamboo rats are common pests, burrowing under crops and eating out their roots, but they are also a source of meat for the rural poor in China. While the idea of eating a rodent disgusts most westerners, it really boils down to culture. Bamboo rats are cheap to raise and provide a surprising amount of meat. Seriously, look at how big they get.

With the risk of disease on everybody’s mind, it seems likely that the bamboo rat trade will die off, but we should remember that the Spanish Flu probably started in either pigs or chickens (evidence points to both being possible), animals that nearly the entire world eats. Close contact with animals is always going to be risky. The trick is mitigating that risk with proper hygiene.

Blind Mole-Rat

Lesser mole-rat - Wikipedia

Максим Яковлєв

Blind mole rats are the most amazingly threatening animals I’ve ever seen. That is just an absurdly horrible mouth, with those perfect incisors ready to slice anything that comes near in half. Despite their name, they’re more closely related to the bamboo rats than the more famous naked mole rats, and they aren’t even blind. Two for two there, guys. They actually see well enough to know when there’s a hole in their tunnel, and even have basic color differentiation. Like a lot of low-light adapted animals, they cannot see red light. This is why you see red lights on several deep-sea fish; most other life down there can’t see it.

Unusually, despite only being distantly related, it seems that living in a similar environment to naked mole-rats has granted blind mole-rats the same resistance to cancer and incredible lifespan. Your average rodent of this size only lives 2-4 years, while a mole-rat can top 20. Part of this is probably helped by the fact that tumors have never been found to naturally occur in any species of blind mole-rat.

Mole-rats have long telomeres on their chromosomes, which put simply means that their cells can divide many, many times. This is part of what allows their longer lifespan, but usually, this would also mean that cells could divide out of control, creating tumors. When cell division gets out of control, the cells release IFN-β, a protein used to carry signals between cells. What exactly it does is unclear, but shortly after this release, the entire group of cells dies off together. As such, mole-rats are entirely cancer free, something that has led to much experimentation about possible cancer cures for human beings.

Naked Mole-Rat

Naked Mole Rat - Heterocephalus glaber

Joel Sartore

So with all that, what makes the naked mole-rat so damn unique? Why is it in so many articles? Well, it has the long lifespan and cancer resistance of the blind mole-rats and adds a whole suite of its own baffling traits, starting, of course with their incredible appearance. I love these bristly little weirdos. They look like an old person’s hand was animated by a necromancer.

Naked mole-rats and the similar Damaraland mole-rat are the only eusocial mammals, meaning they live like ants or bees. A single female is the mother of an entire colony, reproducing with three favored sons (yes, incest) to produce many children that are kept sterile by hormones in their urine (yes, they drink it, no, this isn’t a fetish article, I promise).

Not only are they freakishly long-lived as rodents and indeed any mammals go, they break all kinds of regular mammalian aging rules. Their rate of mortality does not appear to increase as they age like it does in regular mammals, meaning they likely age exceptionally slowly or much later in life than most mammals, and breeding animals live longer, rather than shorter. In nearly every tested animal, not spending energy on reproduction allows an animal to live longer, but in naked mole-rats, reproduction activates genes not normally expressed that have to do with muscular regeneration. In addition, non-reproducing workers are nearly identical between males and females, with no sexual dimorphism.

Aging isn’t all naked mole-rats are weirdly resistant to. They also resist pain from several common defensive chemicals used by plants and animals alike. Acids which cause extreme pain in most mammals are completely ignored by them, allowing them to chomp down on spicy tubers and ignore angry ants (the default mode of ant) to their heart’s content as they go about their business.

Something else they simply ignore is the need to breathe. In their underground homes, there is often a lack of oxygen, but non-conformists that they are, naked mole-rats eschew such mainstream needs. They have uniquely efficient pathways for breaking down glycose without oxygen, providing energy for their cells and preventing tissue death for nearly 20 minutes with literally no oxygen or hours of low oxygen. For comparison, humans suffer permenant brain damage if their oxy-guzzling Hummer brains don’t get any fuel for a mere 3 to 6 minutes.

Especially strangely, unlike literally all other mammals, naked mole-rats are ectotherms and poikilotherms. What exactly does that mean? Well the first means that they can’t regulate their own body temperature. In layman’s terms, they’re cold-blooded, like most reptiles. The second means that their body temperature varies considerably rather than being stable. Unlike lizards, which bask in the sun to raise their temperature before moving, naked mole-rats don’t go outdoors, just relying on ambient heat in their tunnels, and their hairless flesh isn’t particularly effective at holding heat.

So in other words, naked mole-rats look decayed, can survive without oxygen, feel no pain, live forever by rodent standards, and have no body heat. The only conclusion? They’re undead, led by their necromancer queens to strip the land of all living… tubers. Uh. They’re not the most threatening zombies, I will admit. Just the coolest.

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2 Comments

  1. Wait, blind mole-rats can see? How!? That thing doesn’t even have eyes! What are they, Kung fu monk-moles?

    Naked Mole-rats are cool though. Breeding to live longer?! Now ain’t that just the dream!

    • They have eyes, they’re just under a layer of skin. Turns out they’re still functional down there.

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