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  • 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.

  • Mammals need a lot of oxygen;

  • we use it to make the energy that fuels everything

  • from maintaining our body temperatures

  • to our heartbeats

  • to voluntary movements.

  • Without oxygen, we quickly die.

  • In fact, no other mammal could survive the oxygen depletion

  • experienced in a naked mole rat colony.

  • 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.

  • Most mammals are warm-blooded,

  • meaning they have to keep their body temperature consistent.

  • Naked mole rats don't get enough oxygen to do this.

  • Instead, they're the only mammals

  • whose body temperature fluctuates with their environment,

  • making them cold-blooded, like reptiles.

  • They also have a special type of hemoglobin,

  • the molecule in the blood that transports oxygen.

  • Their hemoglobin is much stickier for oxygen than ours

  • and can pick oxygen up even when it's scarce.

  • 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.

  • Human brain and heart cells have some cellular machinery to use fructose,

  • but not nearly as much as naked mole rats.

  • Naked mole rats are, in fact, the only mammals known to have this ability.

  • While we can hope humans won't ever need

  • to exclusively live in underground tunnels,

  • there are many situations where we would benefit from needing less oxygen.

  • During heart attacks and other medical emergencies,

  • people often die or sustain debilitating organ damage from oxygen deprivation.

  • Could we replicate the naked mole rat's use of the fructose pathway

  • for human health?

  • It took millions of years of evolution to bring the behavior of an insect,

  • the temperature regulation of a reptile,

  • and the energy production of a plant

  • together in one little mammal,

  • but maybe, with enough study,

  • we can replicate just a few of their wild adaptations.

What mammal has the social life of an insect,

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B2 US TED-Ed mole oxygen naked fructose colony

Are naked mole rats the strangest mammals? - Thomas Park

  • 1998 257
    April Lu posted on 2018/05/31
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