Unable to feel most types of pain and resistant to most forms of cancer, you’d think naked mole rats were already the superheroes of the animal world. But as if that wasn’t enough, they have another power to add to their abilities: They can survive in environments with no oxygen for almost 20 minutes.
As bald, wrinkly rodents with teeth, naked mole rats are already some of the weirdest creatures around. But as researchers have begun studying the “sabre-toothed sausages”, they’ve uncovered that the creatures are even freakier than we thought. It now seems that the mole rats are able to avoid anoxia by switching to a metabolic strategy usually thought to occur only in plants.
Living underground in the dry grasslands of the horn of Africa, the mole rats are strange for a number of reasons. The rodents were the first mammals discovered to live in eusociality. More commonly associated with social insects such as ants, termites, and bees, the creatures form societies based around a single breeding female, while most of the rest of the colony live as non-breeding workers, who dig the tunnels, forage for food, and care for the young.
It's this highly social, subterranean lifestyle that is thought to be why the animals have evolved to tolerate higher levels of pain and is possibly the driving force as to how they can survive in environments with zero oxygen. With so many bodies living and working in poorly ventilated tunnels, the little oxygen that is down there gets used up incredibly quickly.
Researchers from the University of Illinois at Chicago wanted to see exactly how little oxygen the sausage-rats can tolerate. They placed both mole rats and normal mice into chambers and lowered the oxygen level to see how long they can survive. When the level was taken to zero, the mice died within a minute. But the mole rats were able to survive for up to 18 minutes, and returned to full function when levels were put back up again. Their results are published in Science.
Mammals need oxygen in order to convert glucose into energy. When oxygen levels drop, the brain cells are starved of this vital gas, cannot make energy, and thus die. The researchers noted that in the mole rats, when oxygen levels were low, the level of another sugar, fructose, increased in their blood. They found that the rodents had shifted to breaking down fructose in their brain cells, a process that does not require oxygen. In essence, they metabolize fructose when oxygen is absent, in a similar fashion to plants.
While inefficient, the switch allowed the mole rats to enter a sort of coma and survive until oxygen levels returned to normal.