Naked mole rats are small, furless mammals. They live mainly in the regions of Ethiopia. They spend their entire lives in underground tunnels, which they dig themselves with their teeth and claws. They have adapted to life underground by being able to walk in either direction along a tunnel; they move just as quickly backwards as they do going forwards.
A naked mole rat is about 10-15cm long. Its claws are its main digging tools, covered in a velvet-like substance. It also uses its nose to move loose rubble out of the way. The rat's nose is like that of a cat and it can sense ground vibrations which is useful when digging a tunnel or searching for food. It also uses the hairs on its nose for finding its way around the numerous, labyrinthine tunnels. Eyesight is not an important naked mole rat attribute, because in a tunnel underground you are more likely to smell, hear or feel a predator before you ever see it, so a naked mole rat has evolved to make do with very little eyesight. This means that its eyes can easily be damaged by exposure to sunlight. A mole rat's teeth grow from above and outside of its lips, allowing it to use its teeth for tunnelling without getting its mouths full of soil. These teeth grow continuously, so a rat has to keep gnawing away to file them down. When naked mole rats are kept in captivity they are usually given a block of concrete to chew on.
Naked Mole Rat Society
The naked mole rat hierarchy is a very simple one. At the top there is a king and a queen, and the queen will spend her entire life breeding. All other rats are workers of some description.
The queen plays a very important role within the colony. Naked mole rats are the only known mammals that operate a hive system, in the way that insects do, with one queen who does all the breeding and lots of workers who have no children of their own. Scientists don't yet understand why they do this, as evolution favours the individual1 and workers should have more to gain from having children themselves.
The labourers build new tunnels and expand the society of the moles. Life for a worker mole is hard. They are often worked to death and get minimal food and water.
The third type of position in naked mole rat society is that of the warrior. This could be a sentry guard, who will alert the naked mole rats if a predator approaches, or it could be a slave driver who keeps the workers in check and who drags off any naked mole rats that die through exhaustion. Naked mole rats have many predators in the wild so warriors are very important. They also use teamwork to defeat enemies. A good example of this is when defending against a snake. The rats' defence against snakes involves a soldier attacking the snake while the workers kick dust into the tunnel behind it to protect the queen.
The king in a naked mole rat society can be easily overthrown; this is because the queen will want new genes into her family. Worker naked mole rats often make a run for it. They wait until it is night and run as fast as they can out of the tunnels. Once outside, the naked mole rat runs toward the nearest other naked mole rat society, one that is obviously not their own. They can run for up to ten miles in order to find a new home. The worker naked mole rat can normally fight its way through the sentry guards, and any other guards it may meet. However, if it is caught it will be killed.
The way a naked mole rat can tell the difference between a member of its own society and a member from another is because each society's underground toilet chambers are constructed in a way particular to that group, and each group carries the distinctive odour of its own latrine. This makes it easy for the intruder to distinguish friend from foe. Once past the guards, the naked mole rat heads straight towards the queen; the fact that the rat is a visitor from a different society gives him elevated sexual status, thus he will spend the rest of his short life breeding. Unfortunately, a female worker naked mole rat cannot do the same as the male and run off to a different home. This is because the king isn't as fickle as a queen, preferring instead to mate with only one other female for life.
Where To See Naked Mole Rats
Naked mole rats are not normally kept in captivity. They need to be kept in large numbers together. But if you do have the space then there's no reason why they can't exist quite happily outside of their natural environment. They are sometimes kept in zoos, for example Bristol Zoo, and there's also a settlement in the Pacific Science Center in Seattle. The best place to see them though is in the wild but this is a rare occurrence.