Friend or Foe? Naked Mole Rats Can Tell By A Unique Squeak

A new study shows that naked mole rats speak with distinct dialects that appear to be learned — and reveal what group they belong to.

Transcript

ARI SHAPIRO, HOST:

Naked mole rats are, as the name suggests, almost hairless creatures. They are mostly blind and live underground in arid parts of Africa. Now, scientists have learned something surprising about how these creatures talk to each other. NPR's Nell Greenfieldboyce reports.

NELL GREENFIELDBOYCE, BYLINE: Alison Barker thinks naked mole rats are sweet and cute. Others see them differently.

ALISON BARKER: Often people think, oh, it's that really weird, ugly animal with the big teeth and the wrinkly skin.

GREENFIELDBOYCE: Barker studies naked mole rats at the Max Delbruck Center for Molecular Medicine in Berlin, Germany. And she says they are really unusual rodents. They can live more than 30 years. They're resistant to cancer and certain kinds of pain. Plus, they're cold-blooded. What intrigued Barker was their constant bird-like chirping.

(SOUNDBITE OF NAKED MOLE RAT CHIRPING)

GREENFIELDBOYCE: She wondered if these calls were involved in maintaining this species' complex social structure. Each naked mole rat colony is ruled by a queen, who mates with just a few males and gets to have all the babies. Everyone else works for the common good. Barker and her colleagues spent a lot of time recording and cataloging naked mole rat calls.

BARKER: We can say now that there's about 25 different sounds that they make.

GREENFIELDBOYCE: One of the most common is a greeting, the soft chirp.

(SOUNDBITE OF NAKED MOLE RAT CHIRPING)

BARKER: And so if you're a naked mole rat and you were walking in the tunnel and you bump into another naked mole rat, which happens quite frequently, actually, you would both emit your own soft chirp.

GREENFIELDBOYCE: The research team focused in on this chirp, recording more than 36,000 examples from 166 naked mole rats living in seven colonies. In the journal Science, they report a surprising finding. Each colony has its own dialect. Its soft chirp is acoustically distinct. When the researchers played soft chirps to naked mole rats in the lab...

BARKER: Almost all of the time, they only responded when they were presented with a dialect that matched that of their home colony.

GREENFIELDBOYCE: To hear the difference in soft chirps, here's some from their lab colonies, which are named after the groups in "Game Of Thrones," like the Martell Colony...

(SOUNDBITE OF NAKED MOLE RAT CHIRPING)

GREENFIELDBOYCE: ...The Arryn Colony...

(SOUNDBITE OF NAKED MOLE RAT CHIRPING)

GREENFIELDBOYCE: ...And the Dothraki Colony.

(SOUNDBITE OF NAKED MOLE RAT CHIRPING)

GREENFIELDBOYCE: To human ears, these differences might seem small, but in naked mole rats, they could lead to some "Game Of Thrones"-style clashes because naked mole rats will attack foreign strangers. Very young pups, however, can be moved from one colony to another. And Barker found that pups will learn to speak the dialect of their adoptive home. A colony's dialect seems to be controlled by the queen. When she dies, there's chaos and infighting and soft chirps sound more variable until a new queen establishes herself.

BARKER: And so we actually think that one of the ways in which the queen maintains her control is to make sure that everyone is, like, rigidly adhering to a certain dialect. And so that becomes, perhaps, a readout for conformity within the colony.

GREENFIELDBOYCE: These findings fascinated Rochelle Buffenstein, a researcher who studies aging in thousands of naked mole rats at Calico Life Sciences.

ROCHELLE BUFFENSTEIN: To me, it appears that naked mole rats are clearly able to learn vocalizations in much the same way that humans and songbirds do and create this language through vocal mimicry, which is unheard of in other rodents.

GREENFIELDBOYCE: And this could give scientists a new way to study the biology of language learning in the lab.

Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.