Mole rats: Safety in the burrows
Some sought safety in burrows, and in grassland which are free of roots of large trees, it is easy to construct extended tunnel systems without hindrance. One of the most specialized of burrowers is the naked mole-rat (Heterocephalus glaber; order Rodentia) of East Africa. It eats the roots of grasses together with bulbs and tubers. Mole rats live in families and excavate elaborate underground quarters with special dormitories, nurseries, larders and lavatories. Life spent entirely underground in the warm, dry earth of the African plains has changed them dramatically. They have lost use of their eyes and are now hairless. These naked sausage-shaped animals have huge incisor teeth that project clear of the head in a bony semicircle in front of the face. They are used for both feeding and as burrowing tools. Gnawing one's way through earth could clearly be a distasteful business, but the mole-rat avoids mouthfuls of soil by pressing back its lips behind the protruding teeth and the mouth is kept tightly shut while the teeth excavate through the soil.