The Naked Mole-Rat

[trolls' bane]

Here's a report I wrote last year in 7th grade for science. I've been planning to put it on here for a while, so now I will.

The Naked Mole-Rat

The naked mole-rat is an interesting-looking animal, with even more interesting habits and behaviors. Naked mole-rats are mammals of the order Rodentia, and belong to the family Bathyergidae. Aside from their common name, they are known as Heterocephalus glaber.

The name, naked mole-rat, fits well with the organism because they seem to have no hair, although they have some stiff hair on their necks and between their toes. They have loose wrinkly skin (due to no subcutaneous fat layer), and have been described as cigar shaped. Together with their pinkish, wrinkly skin and their upper and lower incisors (which meet at their tips), they tend to have a walrus-like face. They are around 2 to 3 inches long, with a 1 inch tail included, and the queen is usually about 4; and they weigh between 1 to 3 ounces. They also have no external ears, and very tiny eyes. These small rodents, surprisingly, live much longer than other rodents of similar size, although no one is sure how long they actually live: certain individuals that have been in captivity for up to twenty years, and are still alive. They can move the same speed both backwards and forwards on all four feet and can even “somersault” in tunnels. They have hairs in their mouth thought to keep the mole-rats from swallowing dirt, which often gets in their mouths since they use their teeth as digging tools. The most interesting thing about naked mole-rats is, by far, the fact that they live in colonies, and their social system, which is called a eusocial system. The eusocial system works as follows: queen => fertile males => soldiers => workers. They are, in fact, the only known mammal that lives in colonies, or even has the hierarchy-like euscocial system

Naked mole-rats are fossorial, which means they spend most, if not all of their life underground. They live on the continent of Africa, where they dig large tunnels that can span up to five football fields in the hard clay soils in the hot and arid regions of Kenya, Ethiopia, and Somalia. Mole-rat tunnels can get very long, with branches going to toilet areas, food storage rooms, nest chambers, and other tunnels. In a single colony, there are usually around 75 or more naked mole-rats, but some colonies can reach up to 300 or more. Sometimes, snakes venture into the holes, but the soldiers and workers push dirt to clog up a tunnel to prevent it from entering. Foreign naked mole-rats are not welcome, and to get a recognizable smell, a mole-rat from the colony will roll around in one of the toilet chambers.
Mole-rats have several strange techniques for survival. Unlike most species, they can’t retain their bodies’ heat, so they huddle together to keep warm. They also need water and food, which they get from underground tubers and roots, which they nourish themselves on.

All naked mole-rat colonies include both males and females, but only the queen and 1 to 4 males can reproduce. They and the rest of the colony are protected by 2-4 soldiers. Mole-rats, like all mammals, reproduce sexually. The others are kept “un-fertile” due to them being constantly pushed, scratched, trampled and trodden on by the queen. If the queen happens to notice (or more likely, sense) that another female mole-rat has the potential to reproduce, she will then direct most of her brute force toward that individual mole-rat instead. Litters include anywhere from 1 to 27 or more pups, with about five litters a year. The pups formed as live birth, and are cared for by workers. At 1 to 2 months, the pups are weaned, and can start working with the other naked mole-rats.

These fascinating creatures are a scientific wonder. They are the only known mammalian species that lives in colonies and in a eusocial system. They are among only a few that get all the nutrition that they need from just roots and tubers. The reasons I chose the naked mole-rat is because they are uncommon, I was interested in their social system, and I like rodents (I have 12 rats).