Naked Mole Rats Don’t Get Cancer. Scientists Want to Know Why.

Heterocephalus glaber breaks most of the rules that apply to mammals. It is cold-blooded, which mammals are not supposed to be. It lives in a eusocial colony with a single breeding queen, a system found in insects but almost nowhere else in mammals. It feels no pain from acid or capsaicin. It can survive 18 minutes without oxygen by switching its metabolism to fructose, a trick no other mammal can perform.

And it does not get cancer.

In over 40 years of keeping naked mole rats in captivity, researchers have documented fewer than a handful of cancer cases across thousands of individuals. The animals live up to 37 years, roughly ten times longer than a mouse of similar size, and they remain healthy and reproductively active for most of that lifespan. A 30-year-old naked mole rat shows none of the physiological decline that a 3-year-old mouse shows.

The cancer resistance appears to come from multiple mechanisms working together. The cells of naked mole rats produce a sugar called high-molecular-mass hyaluronan at concentrations roughly five times higher than in human or mouse cells. This substance creates a physical barrier that prevents cells from crowding together, and crowding is one of the triggers for the uncontrolled cell division that produces tumors. When the gene responsible for producing this hyaluronan was removed from naked mole rat cells in laboratory experiments, the cells became susceptible to cancer transformation. The hyaluronan appears to be a significant part of the answer.

There are other mechanisms too. The ribosomes of naked mole rats, the cellular machinery that produces proteins, make fewer errors than those of other mammals, reducing the accumulation of damaged proteins that contributes to aging. Their cells are unusually resistant to stress. Their DNA repair mechanisms are more active than in comparable mammals.

The Colony

A naked mole rat colony contains between 20 and 300 individuals organized around a single reproductive female, the queen, who is the only female that breeds. The queen is physically larger than other colony members and suppresses the reproduction of other females through behavioral dominance and possibly chemical signals. When the queen dies, the colony does not collapse. Several females compete to become the new queen, and the winner undergoes physical changes including elongation of the spine to accommodate larger litters.

The non-reproductive colony members, called workers and soldiers, perform tasks including tunnel excavation, food transport, pup care, and defense. The division of labor is not rigid in the way it is in ant or bee colonies, with individuals shifting between tasks based on colony needs and their own size and age.

Tunnel systems excavated by colonies can extend for several kilometers through the dry soils of East Africa, where naked mole rats live in Kenya, Ethiopia, and Somalia. The tunnels maintain a stable temperature and humidity that allows the animals’ cold-blooded physiology to function without the energy cost of thermoregulation.

What the Cancer Research Means

The practical implications of naked mole rat cancer resistance for human medicine are real but not straightforward. The hyaluronan mechanism is being studied actively, and understanding how it prevents tumor formation could inform cancer prevention strategies. The longevity mechanisms are similarly relevant to aging research.

What is clear is that the naked mole rat has solved problems that mammalian biology was not supposed to be able to solve. Cold-blooded. Eusocial. Cancer-resistant. Oxygen-independent for nearly 20 minutes. It is an animal that looks, frankly, like something that should not exist, and it has been quietly not getting cancer in the soils of East Africa for millions of years while the rest of us were not paying attention.

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