To find their way around underground, the mole-rats use their developed sense of smell, which is the more “common” sense, and they also use the Earth’s magnetic field, which helps them figure out exactly which direction they are headed in. By the way, they can walk both forwards and backwards with the same skill. Since their burrows are narrow and there isn’t always room to move around, mole-rats can move backwards (in reverse) just as well as they move forwards.
Remember that they can’t see where they are going in any case, so it isn’t so important where their eyes are located. Another interesting fact is that the naked mole-rat does not feel any pain from external wounds (like burns, cuts, or abrasions). They never go above ground. Not if it’s up to them, in any case. The entire family lives in a closed system of burrows, which are composed of a number of chambers with different functions. There is a children’s chamber, a bathroom chamber, and food storage chambers, which are all connected by burrows. Mole-rats are completely adapted to underground life, so much so that if they stay above ground, so much so that if they were to spend too much time above ground, they simply wouldn’t survive. Since sunlight never reaches the burrows, their eyesight is poor, and their eyes are tiny.
Also, since sunlight never reaches the burrows, mole-rats don’t need to defend themselves from the dangerous effects of the sun’s rays, so they don’t have any pigments, and their skin is pinkish to transparent. Even if they had any kind of color, no one would be able to see it at night. The mole-rats have even lost their fur (hence the name “naked mole-rat”), because they live in a warm environment, and they almost have no need for insulation. In fact, the local climate and life in the subterranean burrows have made the naked mole-rat almost completely incapable of independently regulating its body temperature. This is another unusual trait for a mammal. When the mole-rat is eventually subjected to cooler temperatures, it regulates it body temperature through behavioral means – like caterpillars, for instance.
The mole rat is also unusual in how it communicates. Besides hearing noises and smelling, which are two more accepted methods of communication, the mole-rat communicates by tapping on the ground. To send messages throughout the burrow system, mole-rats use their heads to tap on the walls of the burrows, and other mole rats rest their heads (or, to be precise, their jaws) on the burrow walls, sense the movement caused by the tapping, and decipher the encoded message. Another problem that mole-rats need to face due to their underground lifestyle is the low concentration of oxygen and the high concentration of carbon dioxide. Since the burrow system is a closed system, it has very little ventilation, and fresh air only enters the burrows on rare occasions.
Mole-rats have also adapted to these conditions, and they can survive under rather extreme conditions of gas concentration. For example, humans can tolerate a decrease in the concentration of oxygen from the level of 21% (the regular concentration of oxygen in the atmosphere) to a minimum level of about 16%, and even then, these conditions aren’t too comfortable. In contrast, mole-rats can survive and even stay active at an oxygen concentration level of 8%.
But surviving underground isn’t enough. They need to move around, too. They’ve even developed special adaptations for this purpose as well. First of all, their incisors, which they use for burrowing and eating, are outside of their mouths! In fact, their lips close behind their incisors, so that when they burrow or gnaw on food underground, sand doesn’t enter their mouths.