Rodent

Rodents are mammals of the order Rodentia, characterised by a single pair of continuously growing incisors in each of the upper and lower jaws which must be kept short by gnawing. Forty percent of mammal species are rodents, and they are found in vast numbers on all continents other than Antarctica. Common rodents include mice, rats, squirrels, porcupines, beavers, guinea pigs, and hamsters. Rodents use their sharp incisors to gnaw wood, break into food, and bite predators.

Even-toed ungulate

Chondrichthyes