He's our honeymoon Hambil. So he's 18 months old + however old he was when we got him, so 18-20 months I guess.
Hamsters are of the subfamily Cricetinae within the superfamily Muroidea.
Gerbils are of the subfamily Muridae within the superfamily Muroidea.
Both are of the order Rodentia.
While Hamsters are more related to voles and lemmings, gerbils are closer to mice and rats. It is generally believed (but difficult to prove) that gerbils evolved from hamster-like animals sometime in the early Miocene period about 23 million years ago.
The groundhog on the other hand, while still of the order Rodentia, is from the family Sciuridae, along with squirrels and chipmunks. They are an older species that it is believed to have survived mostly unchanged since the late Eocene period, about 37 million years ago.
Hamsters live about 3 years, but can in some cases live as long as 7, though that is rare.
The main differences between hamsters and gerbils as far as pets go, is hamsters have no tail, are nocturnal, and prefer to be alone in a cage. Gerbils are social and need to have a friend in the cage, and have tails and are not nocturnal. Both species love to run on wheels and have very similar diets.