Rodents form the largest group of mammals. They are spread around the world and populate the most varied habitats.
Their most important characteristic is their dentition. It has enlarged incisors in the upper and lower jaws. The incisors are also called nail teeth. They are rootless and grow all their lives. So they are gnawed to gnaw. Only in this way can they wear their nails regularly.
Most rodents are nocturnal or dawn-active. However, many are also to be found during the day. They live individually or in groups.
The smell is predominant in many species. The sense of touch (body of the trachea on the head, burst and abdomen, as well as the anterior limbs) often replaces the sense of vision when to find their way.
They have an excellent learning ability (for example, rats).
Small rodents usually live less than 2 years.
Some rodents (example rats) transmit and spread diseases. They also interfere with human life as spoilers and destroyers of food.