Hi everyone, welcome to another “Put the Sci in your Fi” post! Today, we’ll be continuing the discussion of real life superpowers with the naked mole rat.
If you’re new to this line of posts, the previous topic discussed the tardigrade and what superpowers it had that could be useful to the sci-fi world. But, what on earth is so great about the naked mole rat? It looks like a sausage with giant buck teeth, after all. It lives strictly underground in East Africa, and can’t even go outside without being baked to death in the desert sun. Where does its superpower come in?
Well, a little digging reveals that the naked mole rat might just be the tardigrades of the rodent world—they boast a cornucopia of survival mechanisms, including pain resistance, aging resistance, hypoxia resistance, and cancer resistance. On top of that, they can be remarkably long-lived. The typical rodent lives approximately 2-3 years under captive care, while the naked mole rat can live up to 30 years under the same care. Even in the wild, breeding females, queens of their colonies, can live up to 17 years compared to other wild rodent counterparts which only last a season or two (Ruby, 2018).
What exactly makes them so different from other rodents that they can live up to 10 times longer?
For one, they break Gompertz’s law of mortality, an equation devised by Benjamin Gompertz in 1825, that describes age vs mortality rate. Human mortality rate doubles roughly every 8 years after age 30.
By contrast, the naked mole rat (NMR) does not age the same way as other animals—the physiological declines and hazards usually associated with aging plateaus for these creatures. Rochelle Buffenstein has been studying colonies of NMR for 30 years, and even with >3000 data points, says she is unable to see the same signs of aging and deterioration in these rats compared to other mammals (Ruby, 2018).
Scientists have begun to decipher the factors contributing to cancer resistance in the NMR. One key is a high molecular mass version of hyarulonic acid, or HMM-HA. It is suspected that this trait developed in the NMR due to increased need for elasticity in the skin, which would provide a huge advantage in their subterranean world. We have hyarulonic acid too, in places like synovial fluid, or connective tissues such as skin and cartilage. But ours are a much lighter version of the NMR’s HMM-HA—5 times lighter, actually. Why does that matter? Because when the NMR’s cells secrete this stuff, it creates a matrix outside of the cells that prevent cells from becoming too densely populated, and arrests cell growth (termed “early contact inhibition“)—both of which are key features in cancer development. In a study performed by Tian, et al, in 2013, when the NMR’s ability to produce HMM-HA was taken away, cancer developed in the experimental rats, indicating that HMM-HA played an important role in resistance to neoplasm development.
So what does this mean for your sci-fi character?
Well, if you want to give your character HMM-HA, chances are it’ll affect their appearance. Maybe they’ll look quite youthful, or maybe they’ll develop super elasticity in their skin. Or, if you wanted to stretch the superpower even further (pun fully intended) and throw some super HMM-HA overproducing cells in there, the character coooooould develop Elastigirl-like abilities.
Now, HMM-HA alone wouldn’t be sufficient to confer such qualities (I mean, it’s not like you can stretch out a NMR, right?), but combined with some other science-y things (and the fact that you’re writing fiction), it might just be plausible. But it would still require a stretch of the imagination (okay, I’ll stop.)
Next up — the NMR’s remarkable ability to survive oxygen deprivation. These rats can tolerate hours of low oxygen environments and survive 18 minutes with no oxygen at all. Again, evolutionarily, this makes sense as subterranean burrows can be low in oxygen, sometimes dropping down to 6% (whereas above ground, atmospheric O2 is normally at 21%). The average humans, by contrast, can last only a few minutes at most. There is a 22 minute Guinness world record held by Danish diver Stig Severinsen, but this is a feat achieved by years of rigorous training which slowly increased his lung capacity.
Obviously, the NMR hasn’t developed a training routine. Instead, Park, et al, showed in their study that NMRs rely on a metabolic switch to anaerobic, fructose-fueled glycolysis during times of low O2 levels. While in a mouse, tissues able to metabolize fructose are limited to the kidney and intestines, the researchers discovered that all NMR tissue types, including brain, heart, liver and lungs, were able to take up fructose, thus allowing all body tissues to avoid hypoxic-induced tissue damage. With this ability, they are able to metabolize fructose sugars anaerobically, allowing them an alternate energy source.
Last but not least: pain resistance. Omerbašić, et al, showed that the signaling pathways a nerve uses to communicate pain is less effective in the NMR than it is in a rat. Normally in humans and animals, tissue injury around sensory neurons kicks off a string of chemical signals, starting with Nerve Growth Factor (NGF), that increases pain sensitivity and tells the brain, “hey, this is pretty painful, stop touching the thing.” And that’s generally enough to get the animal to move away.
But, this series of chemical signals don’t work as well in the NMR. Why? Omerbašić’s research indicates this effect is actually not due to a change in NGF itself, but due to a single mutation in the NGF-receptor on the nerve cell. Remember, this is a chain of chemical signals, so if there’s a weak link in the chain, everything downstream of that link will be affected. (Also, note that this is not a complete absence of pain as that would be detrimental—the body needs to feel pain to know it’s hurt—but more of a compromise.)
So, all bundled up, what could that mean for a sci-fi character? Well, in the end, you might have a character who’s old, but youthful looking (mmm, Wolverine), can stretch out (yay Elastigirl!) and can stay underwater for a good 10 minutes before needing to come up for air (could be quite useful, actually), all while having a high tolerance for pain. All told, not bad. And all this could potentially come from just the humble naked mole rat.
Thank you for reading! As always, if you have any questions/feedback, please leave them as comments below. Or, if you have any particular topic you’d like to see addressed in future posts, please share!
Till next time!