Syrian hamster babies (Mesocricetus auratus). Hamsters are rodents belonging to the subfamily Cricetinae. The subfamily contains about 18 species, classified in six or seven genera. Almost all hamsters sold in pet stores are Syrian. Hamsters come in lots of different colours and shapes. Because they are easy to breed in captivity, hamsters are often used as lab animals and kept as pets in more economically developed countries. Over recent years they have become a popular housepet.