Monday, November 2, 2009

Why God Made Naked Mole Rats




I've always been a fan of naked mole rats.  It's true; I've been known to drag friends to our Seattle Science Center so they can join me going ga-ga over these absolutely bizarre and awesome--as in causing true awe--creatures.  So I was delighted to find one of my favorite mammals in the news again, this time helping humans avoid cancer.

A new article in the Proceedings of the National Academy of Sciences, covered by the New York Times, explained why these hairless, nearly-blind, eusocial 3-inch-long burrowers who eat their own poop and live up to 28 years never get cancer.  Apparently it's because they, like us, have a cancer-inhibiting gene called p27kipl that kicks in when cells are invaded.  But those queer Eastern-African Heterocephalus glabers, whose teeth are outside their lips, and who can nearly turn around their bodies within their floppy skin, have a first-level defense, an additional gene, p16ink4a that repels cancer upon immediate contact.  It's discovery of that extra cancer-fighting gene that interests scientists and made news.

But naked mole-rats are worthy of fanclubs for many of their astonishing characteristics.  For example, scientists are also trying to glean how it is that the tunnelers don't feel pain when exposed to acids or hot chilis that cause torturous burning in every other creature.  Apparently mole rats lack a neurotransmitter, but weirder yet, according to National Geographic News, "The researchers also found that nerve connections in the naked mole rat's spinal column are different than those of any other animal."  Once they figure out the unique mole-rat nervous system, they can adapt it to spare humans chronic or post-operatic pain.

But that's not all.  They're also teaching us how we might combat all sorts of deadly conditions caused by lack of oxygen. Naked mole rats, while mammals, are cold-blooded, but have no means (like perspiration or fever) to maintain body temperature. They spend virtually their whole lives in close underground quarters, in earth so compact they've evolved so they can function beyond 14 hours in just 3% oxygen (our air has 21%).

They live in colonies averaging 75 (but up to 300) members, all with well defined roles. There's the queen, who, after vanquishing all challengers, grows the space between her vertebrae so she can churn out four or five litters per year of up to 27 pups each, with her three hunky consorts. There's the support crew, who tends the young. There are egalitarian male and female soldiers, who rush forward when they whiff a predator (usually a snake) and fight him off, shoving dirt in his face, clawing at him, and occasionally, for some altruistic souls, sacrificing themselves.  Then there are the workers, who use their tusk-like pairs of incisors (that move separately!) to make miles and miles of tunnels, replete with turnouts, latrines, nurseries, mess halls and communal bedrooms, all in search of food.  They talk, by the way, with chirps, and when a digger hits pay dirt, he returns to wave a chunk of his find, chirping loudly to summon the others to retrieve the bounty.

They find their sustenance by luck, and have been known to unwittingly burrow mere inches from a juicy target. Cuisine for a mole-rat is tubers, those fat roots of plants in the Sahara, where it may not rain for years, selflessly shared by all.  Mole-rats do not drink, and host special symbiotic bacteria and protozoa who help them digest tough fibers.  They carefully gnaw out only the inside of the tuber, so it can regenerate, thereby feeding the commune for years. Which is a good thing, because food can get mighty scarce, and when it does, the mole rats drop their metabolisms by 25%, from already half that of a regular rodent--perhaps one reason why they live ten times longer than a mouse.

If they can survive lean years, and never get cancer; if they can dig a mile-long labyrinth in three months, if they can fight off predators and maintain social order--how do other colonies get established?  After all, naked mole rats, called "sand puppies" by native Africans, are rife, with a conservation status of "least concern."  It turns out that even in mole-rat colonies, a few square pegs may not fit in the round holes.  Research by biologist Justin O’Riain of Cape Town University found that a few fatter and lazier ones get wanderlust, heading topside and journeying by night as far as a mile to find a similarly-inclined mate to start a new colony.

I'm not sure what we're supposed to learn from that, but it's Jewish teaching that we are to learn about God and about human behavior from animals, and naked mole rats seem to have plenty of messages to share.

If you, like me, are captivated by naked mole-rats, you'll love this Smithsonian zoo site, and want to peek at the naked mole-rat cam.

5 comments:

  1. Do you think they're cute? Or hideous? I know it's what's inside them that counts, but just wondering...

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  2. Mink, can't decide if they're cute or hideous, actually, but they sure have charisma! They're so very weird and unique, I can't get enough of 'em! Maybe it's strange (well, it surely is) but they really do get me wondering what God had in mind....

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  3. I can only skim the blog as I can't look at the pictures for but a few seconds. At the Science Center I run past creatures. Maybe God had in mind that some things should be avoided. But in the end if these creatures help us unlock some cure for dreadful diseases I will gladly be corrected.

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