Sex and longevity

A Roborovski Dwarf Hamster

A female Teddy Bear Hamster with her two babies, who are less than one week old.
Syrian hamsters typically live no more than two to three years in captivity, less than that in the wild. Russian Hamsters (Campbell's and Winter White) live approximately 1.5 to 2 years in captivity, and Chinese Hamsters 2.5 to 3 years. The smaller Roborovski Hamster often lives to 3 to 3.5 years in captivity. Both Syrian and Russian hamsters mature quickly and can begin reproducing at a young age (4-5 weeks), whereas Chinese hamsters will usually begin reproducing at 2-3 months of age, and Roborovskis at 3-4 months of age.
Left to their own devices, hamsters will produce several litters a year with several babies in each litter. Male and female hamsters are therefore usually kept in separate enclosures to prevent the addition of unwanted offspring. When seen from above, a sexually mature female hamster has a trim tail line; a male's tail line bulges on both sides. Male hamsters typically have very large testes in relation to their body size. Before sexual maturity occurs at about 4-6 weeks, young hamsters are more difficult to sex. When examined, female hamsters have two holes close together, whereas males have anal and genital openings further apart than the female's. (The penis is usually withdrawn into the coat and thus appears as a hole or pink pimple.)