These animals grow to between 82 and 127 mm in body length (tail length 20–33 mm) and weigh 1.7 grams at birth, then as they get older can weigh 30–45 grams. They live two to three years on average. A Chinese hamster's body proportions, compared with those of other hamsters, appear "long and thin" and they have (for a hamster) a relatively long tail. Males have a relatively large scrotum, therefore females were generally kept as pets and males used solely for breeding and research purposes, until scientists started using other rodents, albino mice and rats. Chinese hamsters are not related to the social "dwarf" hamsters. The term "dwarf" is often used to refer solely to animals in the genus Phodopus, (the two types of Russian dwarf hamsters and Roborovski dwarf hamsters).
The wild colour is brown with a black stripe down the spine, black and grey ticks and a whitish belly. This coloration, combined with their lithe build and longer tail, makes them look "mousy" to some eyes and, in fact, they are members of the group calledratlike hamsters. Besides the wild colour, a well-known variation is the white-spotted Chinese hamster, which often is grayish white all over, with only a dark stripe on its back.
They can have quite vicious temperaments, but are easily handled; one of their endearing traits is that of clinging to a finger with all four paws, rather like a harvest mouse on a corn stalk. Chinese hamsters can be quite nervous as youngsters but, once they are tame, can display an endearing calmness and gentleness of character.
In the past, Chinese hamsters were commonly used laboratory animals, until they were replaced by the common mouse and rat, which are easier to keep and breed; however, quite a few biotech drugs are still being produced by putting the gene for the protein into Chinese hamster ovary cells, which then produce the protein.
Of note, some United States states such as California and New Jersey regard the Chinese hamster as a pest, and as a result require a special permit to own, breed or sell them. Some states, including New Jersey, call it an exotic animal, and require a similar permit in order to sell them.
Only three known colour mutations are found in Chinese hamsters, normal/wild type, dominant spot and black-eyed white. Normal and dominant spot are readily available in the pet trade throughout the United Kingdom (UK), whereas the black-eyed white is extremely rare; only a few are owned by hobbyist breeders in the UK.
Naming of the Chinese hamster and the closely related Chinese striped hamster are confusing. Some people consider the Chinese hamster (Cricetulus griseus) and the Chinese striped hamster (Cricetulus barabensis) different species, whereas others classify them as subspecies, in which case the Latin name of the Chinese hamster becomesCricetulus barabensis griseus.