Red Squirrel

A red squirrel.

Rodents form the largest extant order of mammals known, Rodentia, making up nearly half of the 4,000 species of the entire class. The largest extant species is the capybara, with adult males growing to be as large as adult sheep. A large number of rodents are harmful to people, particularly through carrying diseases, which once killed a quarter of Europe's human population.


Generally, rodents are quite small, with few exceeding 20cm long, which is smaller than many frogs (indeed, mice can fall prey to the larger species) and birds. They also have a generally good sense of smell. They can digest a very wide range of food items (and materials, too) and breed very quickly compared to other mammals. Males are generally larger than females.