Hamsters are rodents belonging to the subfamily Cricetinae. The subfamily contains about 25 species, classified in six or seven genera.
Hamsters are crepuscular animals which burrow underground in the daylight to avoid being caught by predators. Their diets include a variety of foods, including dried food, berries, nuts, fresh fruits and vegetables. In the wild, they feed primarily on seeds, fruits and greens, and will occasionally eat burrowing insects. They have an elongated pouch on each side of their heads that extends to their shoulders, which they stuff full of food to be stored, brought back to the colony or to be eaten later.
Hamster behavior varies depending on their environment, genetics, and interaction with people. Because they are easy to breed in captivity, hamsters are often used as laboratory animals. Hamsters have also become established as popular small house pets, and are sometimes accepted even in areas where other rodents are disliked, and their typically solitary nature can reduce the risk of excessive litters developing in households.