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Heterocephalus glaber Region: Arid regions of central and eastern Ethiopia, central Somalia, and Kenya |
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Cooperation is Key Rodentville Naked mole-rats are rodents that live under ground in the deserts of Africa. They are found in tight-knit colonies of 20 to 30 (and occasionally up to 100) members. A complex series of burrows and connecting tunnels protect these rodents from the harsh desert conditions above ground. It’s like an underground town, and they rarely leave it. They scurry through the tunnels, moving backward as fast as they move forward. Looks aren’t everything To us, naked mole-rats may not be the most attractive of creatures. They are about the size of a thumb, and have little to no hair, with wrinkly pink or yellowish skin. Their eyes are so tiny that they’re almost useless. Naked mole-rats have big, buck teeth (used for digging) that stick out beyond their mouth. It’s not too surprising that some people liken these strange creatures to sausages with legs! Although they may lack in the looks department, naked mole-rats definitely make up for it in other ways. A great social life Lots of mammals live in groups, but few have a social life like the naked mole-rats. Their social structure is more like that of insects---bees and ants, in particular---than like other group-living mammals. There are small, worker mole-rats that do the burrowing, gather food, and bring nesting material into the nest chamber. Larger soldier mole-rats defend the colony against their enemies, like snakes and mole rats from other colonies that are looking to take over. In everything they do, mole-rats cooperate with each other. It shows in their assembly line approach to digging tunnels. The worker at the head of the assembly line chisels away dirt and pushes the loose soil towards the rear with its hind feet, making a pile of soil. Then it scuttles backward through the tunnel, moving the pile of soil with its legs. At the entrance of the tunnel, it gives the pile to the last worker in line, who takes the dirt and deposits it outside. The "dragging" mole-rat then returns to the front of the line, climbing over the others and moving backwards and the whole process repeats. Tunneling is important because it’s how mole-rats get food. They chew into roots and tubers, eating as they go, but leaving enough so that the tubers grow back the following year. Queen of the desert The most important member of the colony is the breeding female, or queen. Much larger than the other mole rats, the queen is the only female who reproduces. She lives in the main chamber of the burrow system, and is tended to by the workers. The queen is definitely the boss. She sometimes leaves her chambers and checks on the workers. The queen rules by her behavior, and possibly through chemicals called pheromones that are released in her urine. When the queen dies, the colony is not stable until there’s a new queen. Several of the larger females may fight, sometimes to the death, to become queen. Royal duty Naked mole rats usually breed once a year in the wild. The queen mates with one to three different males. About 70 days later, a litter of three to 12 pups (and sometimes as many as 25) are born. The pups are born blind, and only weigh about 2 grams. For the first month the queen nurses the pups. Then the other members of the colony take over pup care, feeding them feces until the pups are old enough to eat solid food. Is there night and day underground? Well, sort of. It’s always dark in the mole-rats’ burrow, but they do have a daily pattern. They’re active in the early morning and late afternoon to avoid temperature extremes near the surface. In the desert, it’s very hot during midday and quite cold at night. Mole-rats do most of their digging after it rains, when the soil is softer. Just the facts: Body length: 3 to 3.5 inches Tail length: 1.1 to 1.7 inches Weight: 1.2 to 2.8 ounces Distribution: The arid regions of central and eastern Ethiopia, central Somalia, and Kenya. Naked mole-rats are highly successful in the wild, and are in no danger of extinction at this time. Habitat: Underground burrow systems in hard clay soil Wild diet: Roots and tubers Brookfield Zoo diet: Sweet potatoes, carrots, apples, leafy vegetables, grapes, bananas, mouse biscuits Naked mole-rats at Brookfield Zoo There’s a colony of naked mole-rats in The Fragile Desert, an exhibit about Africa’s deserts. You can watch the mole-rats in a see-through burrow system.  Links |