Ever Seen a Nkd Mole Rat?
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Not a mole, not a rat!
These odd little creatures with pink, wrinkly skin dig and live in underground burrows the way moles do. They have skinny, rat-like tails. Yet these mole-rats are more closely related to porcupines, chinchillas, and guinea pigs than they are to moles or rats and are the only species of mole-rat that has practically no hair.
These creatures live underground in the desert regions of East Africa, a pretty warm place during the day. If it does get cold at night, the little mammals just huddle together in a mole-rat pile and use each other's body heat to keep warm. And since they spend their lives underground, they don't need hair for sun protection.
Most mole-rat species live by themselves. But the nkd mole-rat and the Damaraland mole-rat Cryptomys damarensis are the only two mammal species that are eusocial (yew SO shul). This means they live in colonies that may have several generations living together and just a few individuals that produce all the offspring for the colony, much the way bees and ants live.
A colony may have from 20 to 300 individuals living in an underground area that can be as large as 6 football fields! The area is filled with a tunnel system that stays at a warm temperature of 86 degrees Fahrenheit (30 degrees Celsius), even though the outside temperature can get much colder or much warmer. To keep the colony healthy and safe, there are chambers, or rooms, at different points along the tunnel system. Each chamber has a purpose, just like the rooms in your home. There is the nesting chamber, or nursery, where the queen (dominant female) stays with the pups (babies), and feeding chambers, used for collecting and storing food—a mole-rat pantry! There is even a toilet chamber, where the members go to the bathroom (sorry, no shower).
Most people think they are blind. Their tiny eyes are not much use underground, but they can still see a little bit. However, mole-rats rely on their senses of hearing, smell, and touch more than their sight. Researchers have studied them in light and dark environments and find their behavior doesn't change.
The colony has a specific job for each member and is led by the queen. Only a small group of males is allowed to mate with the queen. The other members in the colony serve as soldiers or workers. If a snake or other predator comes into a tunnel, the mole-rats let out an alarm call to alert the soldiers. Like a little army unit, the soldiers run off to defend the colony with their large, sharp teeth. Several of the soldiers may pile on top of each other to block the way, and all the predator sees is many sets of gnashing teeth! The mole-rats assigned as workers scout for food, dig the tunnels, and care for the queen's pups.
The queen of the colony is larger and longer than all the other mole-rats. Her job is to breed and have pups and to keep her position as the dominant mole-rat in the colony. But the queen is not born into her position: she must earn it. Females will fight, even to the death, for the right to be queen. Once a queen is established, she will actually stretch the space between the vertebrae in her backbone to become longer and get ready to have pups. Her position as queen is never secure and she must continue to fight off other females if she wants to stay in charge. The queen often inspects the tunnels and chambers and tries to keep control of her colony by biting and pushing the other mole-rats to remind them she is the boss.
Eating tough roots and tubers requires some pretty strong and sharp teeth. Their front teeth also help them tunnel through dirt while looking for these food items. Like all rodents, these teeth continue to grow, but by gnawing on hard things, they keep their teeth from getting too long! At the San Diego Zoo they are fed yams, carrots, corn, broccoli, and fruit. Their favorite food item is a banana.
They eat what?
Yucky, but true: they eat their own poop. But there's very good reason for doing this. Roots and tubers are eaten, which are very hard to digest. Their intestines are full of microscopic organisms to help with digestion. But in order to absorb more of the nutrients from their food, they will eat the poop. It's like getting two meals for the price of one. And not only do they eat their feces, they also roll in it! Because they live in the dark, they have nearly lost the use of their eyes. In order to identify members of the colony versus an intruding colony, they all roll around in the toilet chamber. This way everyone smells the same!
(Literature credit: SD Zoo)