Naked mole rats are, frankly, outrageously weird.
The hairless rodents are basically coldblooded, a freakish quirk for a mammal. They live for decades, while mice - nearly identical from a genetic standpoint - live for just a few years. They experience a shockingly low rate of cancer. And perhaps most intriguingly, they're impervious to certain kinds of pain.
Researchers have noted that Heterocephalus glaber (also known as the "sand puppy," which seems generous) doesn't experience "thermal hyperalgesia." That's a phenomenon most animals, including humans, are familiar with: When you get a bit of sunburn, you know that a warm shower will hurt like the dickens. It's the increased sensitivity of pain receptors in damaged tissues, telling your body to be gentle with a wounded area. In some humans, this sensitivity can go haywire and cause chronic pain. In others, a hyposensitivity can leave one dangerously insensitive to pain, making it difficult to judge when tissue is being injured.
Naked mole rats don't really experience this sensation, probably because they live in huge colonies that pack into close, hot quarters where such sensitivity would make life miserable. In a study published today in Cell Reports, scientists tried to figure out the mechanism behind their (metaphorically) thick skin.
"I call them extremophile mammals. That's the way I treat them, just like extremophile bacteria," said lead study author Gary Lewin, a professor at the Max-Delbruck Centre for Molecular Medicine in Berlin. He's fascinated by their ability to live in hot, cramped quarters with little food. He thinks that their insensitivity to pain - and most of their other strange quirks, including the inability to regulate body temperature - simply serve to make their bodies more efficient.