Sexing hamsters can be difficult, especially if they are young or you don't necessarily have both male and female hamsters for comparison. The basic differences are similar for all species of hamsters—Syrian, dwarf, or Chinese. However, each species has different characteristics or features that can aid in sex identification.

Holding a Hamster to Determine Male or Female

Hold your hamster on its back to look at the belly area. You can cup your hand over your hamster and gently turn it over onto its back, or hold the hamster by the scruff of its neck. Holding the hamster in a slightly upright ("sitting up") position will help you determine if testicles are present.

Anogenital Distance

The surest way to tell whether a hamster is male or female is by looking at the anogenital distance. This is the distance between the genital openings (penile opening in male hamsters; vaginal and urinary openings in females) and the anus. This distance is much shorter in females than in males. The two openings can be difficult to distinguish in females, while the space in between is normally twice as long in males.

Other General Differences

A few additional differences apply to all hamsters, although these may be difficult to see, depending on the hamster's age and species.

• The back end of the male tends to be elongated and rounder in appearance in comparison to the female.
• Male hamsters often have a noticeable scrotum with testicles after about four weeks of age, although the testicles can be retracted.
• Only female hamsters have nipples.

Characteristics of Syrian Hamsters

Determining the sex of Syrian hamsters tends to be somewhat easier than sexing other species because the differences between the males and females are relatively obvious. Female Syrian hamsters have relatively visible nipples that appear in two rows running parallel to, and along the sides of, the belly. The nipples are most visible when the hamster's belly hair is short. Male Syrian hamsters have fairly obvious testicles that extend from their hind end. The testicles may be retracted (as with all male hamsters) or hidden by fur, but generally, they are discernible in most cases.

Characteristics of Dwarf Hamsters

Dwarf hamsters have some additional features to help you determine their sex. Male dwarf hamsters have a visible scent gland located near the middle of the belly. There may also be yellow or oily staining around the gland, resulting from the gland's secretions. Female dwarf hamsters have very small scent glands that are difficult to see. Male dwarf hamsters also may be identified by their testicles and the shape of the hind end tapering toward their tails. The testicles are most visible on mature hamsters. Finally, male dwarf hamsters are larger than females, although size is an unreliable measure because it varies by age and the individual animal.

Characteristics of Chinese Hamsters

The most noticeable characteristic of Chinese hamsters is the shape of their hind ends. Males have longer, rounder rear ends than females. However, if you don't have both sexes of hamsters for comparison, you'll have to rely on the anogenital distance for positive identification.