The term PET RODENT, OFTEN refers to two small rodents that are kept as pets, the GERBIL and the HAMSTER. The GERBIL is a small rodent of the subfamily Gerbillinae in the order Rodentia. It is usually 6-12 cm long and weighs between 30-45 grams. The HAMSTER is a small rodent belonging to the subfamily Cricetinae in the family Cricetidae. It is typically 7-13 cm long and weighs between 70-170 grams. Both animals are popular pets due to their small size, low maintenance, and friendly nature.