Queen Naked Mole-Rat (Heterocephalus glaber)

• Type: Mammal Family: Bathyergidae
• Habitat: Underground in arid savannah and grasslands near the equator.
• Location: Parts of Kenya, Ethiopia, and Somalia.
• Diet: Herbivore
• Average lifespan in the wild: 10 years
• Size: Naked mole-rats range from 3-13 inches (8-33 cm); queen is usually largest and longest in the colony.
• Weight: Usually over 1.8 ounces (50 g); may reach 2.8 ounces (80 g).

The naked mole-rat, which is in fact neither a mole nor a rat, is one of only two “eusocial” mammals; as with social insects such as bees and ants, young are produced by only one female in a colony — the queen. In the case of naked mole-rats, the queen mates with one to three breeding males. The colony’s other females are sterile. Research suggests that this is because of the queen’s bullying tactics. She literally shoves around the other females, and her aggression causes the female mole-rats so much stress that it affects their fertility.

But the queen is good to her pups, and tends them diligently — with the help of the rest of the colony. Queens typically produce a litter of about 11 to 12 pups, although litters with as many as 27 pups have been noted. The queen will nurse her pups for about a month, and then the pups join their colony mates on the mole-rats’ regular diet of underground plant parts, like roots and succulent tubers. Naked mole-rats get all of their water from their food (and the queen, dutifully tended to by her subjects, gets all of her food served to her).

Mole-rats are well adapted for life underground. The eyes are narrow slits, and eyesight is poor, but their hearing is acute, and they can sense vibrations; their large, protruding teeth are used for digging, their lips are sealed just behind those teeth so they don’t get a mouthful of dirt as they burrow, and they can move backwards as easily as forwards. The wrinkled, pink or yellowed skin of the naked mole-rat’s tubular body has sensory whiskers on the head and tail, and tufts of hair between the toes, so the feet act like brooms. Other oddities include skin that cannot sense pain, and an essentially cold-blooded metabolism.

Did you know? Naked mole-rat tunnel systems can have a cumulative length of two to three miles.

Related Programs:

• The Beauty of Ugly

On the Web site for The Beauty of Ugly, you’ll get an in-depth look at some of these intriguing creatures. You’ll learn about the remarkable sensory abilities of the weird little star-nosed mole and the unusual social system of naked mole-rats and their imperious mole-rat queen, discover the threats faced by the Cape Griffon vulture, and get a fish-eye’s view of the needle-toothed viperfish and other deep-sea creatures, as photographed by a unique undersea camera called the Eye-in-the-Sea, designed by ocean researcher Dr. Edith Widder.

To order a copy of The Beauty of Ugly, please visit the NATURE Shop.

Online content for The Beauty of Ugly was originally posted online November 2007.