What mammal has the social life of an insect, the cold-bloodedness of a reptile, and the metabolism of a plant?
Bald and buck-toothed, naked mole rats may not be pretty, but they’re extraordinary. With a lifespan of 30 years, their peculiar traits have evolved over millions of years to make them uniquely suited to survive harsh conditions, especially long periods without oxygen.
In the deserts of East Africa, naked mole rats feed on root vegetables. They dig for the roots with teeth that can move independently, like chopsticks.
But even with these special teeth, a single naked mole rat doesn’t stand a chance of finding enough food; the roots are large and nutritious, but scattered far and wide. A large workforce has a much better chance so naked mole rats live in colonies.
Similar to ants, bees, and termites, they build giant nests. Housing up to 300 mole rats, these colonies feature complex underground tunnel systems, nest chambers, and community bathrooms. Also like insects, naked mole rats have a rigid social structure.
The dominant female, the queen, and two to three males that she chooses, are the only naked mole rats in the colony who have babies. All the other naked mole rats, male and female, are either soldiers, who defend the colony from possible invaders, or workers. Teams of workers are dispatched to hunt for roots, and their harvest feeds the whole colony.
Living in a colony helps naked mole rats find enough food, but when so many animals live in the same underground space, oxygen quickly runs out. Naked mole rats can thrive in low oxygen in part because they’ve abandoned one of the body functions that requires the most oxygen: thermoregulation. Naked mole rats are the only mammals whose body temperature fluctuates with their environment, making them cold-blooded, like reptiles.
In response to a real oxygen emergency, naked mole rats enter a state of suspended animation. They stop moving, slow their breathing, and dramatically lower their heart rate. This greatly reduces the amount of energy, and therefore oxygen, they need. At the same time, they begin to metabolize fructose, like a plant. Fructose is a sugar that can be used to make energy without burning oxygen. Usually, mammals metabolize a different sugar called glucose that makes more energy than fructose, but glucose only works when oxygen’s available. Naked mole rats are, in fact, the only mammals known to have this ability.
For more on these weird & cool creatures, check out the TED-Ed lesson Are naked mole rats the strangest mammals? – Thomas Park
Animation by Chintis Lundgren