( Latin: Order Rodentia)
The rodents comprise about a third of all the living mammal species, and they include several of man’s most serious pests. Their most characteristic structural feature is the dentition. Rodents have two large curved incisors in the upper jaw and two in the lower jaw, and these are separated from the remaining teeth by a toothless gap. The actual gnawing is carried out primarily by the lower incisors, while the upper incisors serve to hold the head in position. The shape and size of the tooth marks provide a clue to the identity of the species which has been gnawing.