The naked mole-rat lives like an ant colony and barely seems to age.
Naked mole-rats live underground in colonies run by a single breeding queen, like bees or termites. They can survive 18 minutes without oxygen, feel no pain from acid and live more than 37 years, longer than any other rodent. Remarkably, their risk of dying does not rise as they get older.
The naked mole-rat is a small, wrinkled, almost hairless rodent, 8 to 10 centimetres long, from the dry grasslands of East Africa. It was the first mammal found to be eusocial, a social system otherwise known from ants, termites and some bees and wasps. In a colony averaging 75 to 80 animals, and sometimes over 300, only the queen and one to three males breed. The rest are workers: smaller ones forage and tend the nest, larger ones dig and defend against snakes and rival colonies. When a queen dies, a violent contest decides her successor, whose spine then lengthens to carry litters that can exceed 20 pups.
Life in sealed, crowded burrows means little oxygen and plenty of carbon dioxide, and the mole-rat is built for it. Its metabolism is unusually low, its haemoglobin grips oxygen tightly, and it is the only mammal known to let its body temperature largely track its surroundings. It stays active for at least five hours in air with just 5 per cent oxygen, and has survived 18 minutes with none at all: it loses consciousness, its heart slows from about 200 beats a minute to 50, and it switches to burning fructose, a pathway that keeps working as tissues turn acidic. Its skin lacks a key pain-signalling chemical, so acid and chilli compounds cause no pain, possibly an adaptation to carbon-dioxide-rich air.
Most striking is how it ages. Naked mole-rats can live beyond 37 years, against about 28 for the next longest-lived rodent, and their mortality rate does not climb with age as in most mammals. They are also highly resistant to cancer. Suggested reasons include an extra 'crowding' brake on cell division, an unusually large form of the molecule hyaluronan, very accurate protein production and strong DNA repair. In 2023, mice given the mole-rat's hyaluronan gene lived about 4.4 per cent longer on average.
They are not invincible. Tumours have been found in two zoo animals, both kept in ordinary air rather than the low-oxygen conditions of wild burrows, which may have mattered. Colonies are heavily inbred, but special 'dispersers', fat and restless, try to leave and mate only with outsiders. The species is common, its only sign above ground the little 'volcanoes' of earth it kicks out of its tunnels.
Source: Wikipedia — Naked mole-rat · Text summarised from Wikipedia (CC BY-SA 4.0)
