Hamsters are small rodents. They are popular small pets. For their exercise there are hamster wheel and hamster ball. 19 species classified in seven Genera. The best known species of hamsters are golden hamster and Syrian hamster. A mouse, plural mice, is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is also common house mouse. Mice are also popular as pets.