A New Twist on the Naked Mole-Rat
May 19, 2017
Naked mole-rats may not rank highly on the cute scale, but they are certainly one of the world’s most bizarre and uniquely adapted animals. The naked mole-rat is a mammal, and the vast majority of mammals are warm-blooded. However, naked mole-rats belong to a special group of cold-blooded mammals (along with the platypus and other rare oddities). This unusual fact has been known for a long time, but scientists recently discovered another peculiar naked mole-rat fact: it can survive up to 18 minutes without oxygen. This means that these cold-blooded mammals also have a plantlike metabolism. In no-oxygen environments, naked mole-rates can switch energy fuels from glucose, which requires oxygen to create energy and is the sugar humans and virtually all other mammals use, to fructose, which does not need oxygen to create energy and is the sugar that plants use.
The naked mole-rat is a burrowing rodent of East Africa with wrinkled pink skin. The animal digs using its sharp, chisellike front teeth. Naked mole-rats live in large colonies of up to 300 members, engaging in social behavior similar to that of ants and honey bees. Credit: © Frans Lanting Studio/Alamy Images
Naked mole-rats are small burrowing rodents of east Africa with pink tubelike bodies that are nearly hairless. They are known for their unusual appearance. They can also live up to 30 years—a very long lifespan for a rodent. In addition, they have bizarre social behavior, which rather like that of ants and honey bees instead of mammals. Naked mole-rats live in large colonies in which only one female and one to three males can breed. The rest of the members of the colony only work for the well-being of the colony.
Scientists have known for some time that naked mole-rats regularly tolerate stagnant, oxygen-poor air with high levels of carbon dioxide. But scientists recently put naked mole-rats to a further test by studying them in a 5 percent oxygen environment (a normal oxygen level is about 20 percent). The animals hardly noticed the drop in oxygen, so the scientists cut off oxygen altogether. The result? The animals slowed their breathing and dropped their heart rate, eventually passing out after some 18 minutes. And then, after oxygen was restored, the naked mole-rats popped up and carried on as though nothing had happened! When the mole-rats slowed their breathing and heart rate, the animals were changing their energy system—from glucose to fructose—and metabolized sugar without oxygen. By gaining more knowledge about this metabolic trick, scientists may one day find new ways to treat heart attacks and strokes in humans—conditions in which a lack of oxygen leads to death.
The mysteries of naked mole-rats may never cease. These animals have a social structure like some insects; they are cold-blooded like reptiles; and now we know they can metabolize fructose like a plant. What will these bizarre, wrinkled rodents surprise us with next?
