When is a rat like a bee?

Weird creatures

When it's a naked mole rat. Hidden in underground burrows throughout arid Eastern Africa are the strangest rats you'll ever see. Heterocephalus glaber, the naked mole rat, is the only mammal known to exhibit a truly social system. In other words, they have societies like ants, wasps, and bees.

A colony of 30 to 300 members contains a dominant female (the queen) and one to three male consorts. Groups of soldiers protect the colony, and worker rats dig tunnels and find food.

The name, naked mole rat, appears to be a poor choice. They are neither moles nor completely hairless. Some say their closest animal relatives would be porcupines or guinea pigs.

Only 5 inches long (of which 1-1/2 inches is tail), the rats weigh only an ounce or two. A lack of fat padding under their pinkish-yellow skin makes them appear heavily wrinkled and baggy. They have long, pale whiskers on broad, flattened heads. They have no external ears, and their eyes are small and nearly sightless. They do, however, have the characteristic protruding incisor teeth of rodents, which they use for endless tunnel digging.

The Philadelphia Zoo has two mole-rat colonies. Beth Schwenk, the lead keeper of the Rare Animal Zoo, provides for their care. She points out that the animals are not coldblooded, as some state, although they have "lost their ability to regulate body temperature." To keep warm and ensure the survival of the colony, the animals sleep close together in their burrows. At the zoo, the burrows are kept between 80 to 90 degrees F. at all times.

Mole rats never leave their underground system of burrows. They eat roots, stems, and tubers that they find under the soil. Schwenk says their major enemies are snakes. Snakes locate burrows by looking for the piles of dirt the rats create aboveground while excavating below. But attacking a burrow isn't easy. Soldier rats keep snakes out by banding together and pushing their heads (and fierce teeth) against a burrow opening.

Living in dark underground tunnels, the rats have developed a keen sense of smell. They use it to identify colony members, and will attack anything with an unfamiliar scent.

Beautifully adapted to life under the desert, the mole rat is truly one of nature's strangest mammals.

(c) Copyright 2000. The Christian Science Publishing Society