Syrian or golden hamsters live on average about 2-3 years. Adults are about 6 inches in length. They are solitary animals that should be kept one to a cage. A basic minimum cage size is 12 x 18 inches (and 12 inches tall), but since hamsters are quite active, the bigger the better (and those cute modular plastic hamster cages are often too small for hamsters). Syrian hamsters that are handled from a young age usually have an agreeable temperament, but if not handled much they can be defensive and can deliver a painful bite (they are also nocturnal and can be difficult to wake or act grumpy if woken during the day). Overall hamsters are widely available and make good pets, with the advantage that they can be kept single. Also, several species of dwarf hamster are becoming more widely available. These are smaller than Syrian hamsters and are often more social, at least with others of their species. Some have a reputation as biters, although that depends a bit on the species and how much they are handled.
Care of Hamsters
Gerbils live an average of 2-3 years (although up to 5 years has been reported). They have a body length of about 4 inches, with a furry tail that is almost as long as the body (never pick a gerbil up by that tail, though!). Gerbils are very active and social so are happier as a pair or group (get all males or all females to prevent prolific breeding). Introducing adults is difficult, though, so it is best to acquire a pair (or more) that are littermates or quite young. A recommended minimum cage size for a pair or small group of gerbils is 12 by 24 inches, with a height of 12 inches, although more space would be better. With regular handling, gerbils can become quite tame, and are interesting to watch as they play and interact with their cage-mates.
Care of Gerbils
Fancy mice live 1-3 years on average, and are quite easy to keep. They are the smallest of this group with bodies that are only about 3 inches long, with a long hairless tail. They are also social and females do well in pairs or small groups (males tend to fight if kept with other males). They need a relatively small cage, minimum 12 by 18 inches (and 12 inches tall), although a larger cage is recommended if you have more than a pair. Mice can become quite tame if handled regularly but are small, fast and can be skittish so are not the best candidates for human interaction. However, they are low maintenance and quite active and playful, so they are entertaining to watch.
Care of Mice
Rats live an average of 2-4 years, and make nice pets. They are very social, and it is best to keep a same sex pair (male or female). Since they are larger, with a body length of about 8 inches (and a hairless tail about the same), they are easy to handle. With regular handling they become very tame and enjoy human companionship, and they rarely bite. They need time outside of the cage for social interaction and exercise, and can even be taught simple tricks (they have even been compared to dogs in their ability to bond and interact with people). They do need a large cage: a tall cage with at least 24 inches by 36 inches of floor space is recommended. Due to their social nature they need more time and attention than many of the other small rodents, but make rewarding pets.
Care of Rats
Guinea pigs are fairly long lived, with an average lifespan of 5-7 years (up to 10 reported). At an adult size of about 10 inches long and 2-3 pounds, they are also the largest of the commonly found pet rodents. Their size and gentle temperament have made guinea pigs popular pets, especially for families. They rarely bite, even when stressed. They are social so do best kept in pairs (same sex), and they need a larger cage than is typically found in the guinea pig section at the pet store. A suggested minimum is 4 square feet of floor space for a pair - and this is only if daily exercise outside of the cage is available. Larger cages can be easily created with household materials to create a wonderful habitat since guinea pigs are not escape artists like the other rodents mentioned here. They have slightly more demanding diets, needing a fresh supply of hay and veggies as well as adequate amounts of vitamin C. While they need more space and attention than some other rodent pets, they make rewarding pets and enjoy a longer expected life span.
Care of Guinea Pigs