It has been debated whether the Winter White hamster was a sub-species of the Campbell's Dwarf Hamster (Phodopus campbelli) or not; however, recently it was decided that Winter Whites are of their own species, Phodopus sungorus.
The average lifespan of the Winter White Russian Dwarf Hamster is 1½ to 2 years, although they can live longer.
Feeding your Winter White properly is very important. They need to have constant access to a properly formulated hamster food. Most major brands provide all the nutrition a little hammy needs, and they should live a very long life on those alone. That said, you can of course supplement with small amounts of healthy treats such as carrots, broccoli, washed dandelion leaves, and most other vegetables that are not over-ripe (but very very small amounts of iceberg lettuce). Occasional ham and chicken (very small amounts) is appreciated as well. Avoid sticky foods, apart from a very small amount of cooled thick porridge (which they love, and is very good for them as an occasional treat) especially in their old age. Uneaten fresh food should be removed daily. Beware that some flowers found in domestic houses and gardens are poisonous to hamsters.
Water is the most important of all, as fresh water is needed regularly. You must make sure to change the water in the bottle at least once a week. If travelling with a hamster, remove the bottle so it doesn't drip, but add a piece of fruit or veg with a high water-content (such as cucumber) to their cage for the journey, and replace their bottle as soon as you arrive.
In general, dwarf hamsters typically have more of a family structure than the Syrian Hamster. However, this may be a result of a frequent confusion of the Winter Whites and the Campbell's hamsters. Current research suggests biparental care in Campbell's hamsters (Phodopus campbelli) but not in Winter Whites (Phodopus sungorus). Some report that same-sex pairs and larger groups do not always get along well and frequent fighting may occur and be a great distress for them, or even lead to death.
There are several phases (colorations) of Winter White hamsters: their normal (dark brownish-grey colouring) or sapphire (blue-grey colouring). A white pattern called pearl (white with coloured hairs) sometimes exists in either phase, producing the normal pearl or sapphire pearl forms. However, these colours may be difficult to find, and the range of colours is much narrower than in the case of the Campbell's.
Winter White hamsters, also called Siberian hamsters, come from the steppes of Siberia and Kazakhstan and possess an adaptation not seen in Campbells: they can moult into a white winter coat. This camouflages them against the snow and also gives them their name. This moulting is brought on by the amount of day light; if the hamster is kept in an environment with short duration of day light (< 13 hours of light/day) for more than 6 weeks, they will change into their winter coat (white guard hair with thick inner hair) with only a single black stripe going through the centre of the back. Such seasonal moulting is mediated through the nocturnal secretion of melatonin, the hormone secreted by the pineal gland. Short day lengths also triggers the regression of the gonads in both male and females, and thus Winter Whites become infertile. Because Winter White hamsters show such photoperiodic and seasonal changes in physiology and various behaviours, it is also used as a research model system for studying seasonality and photoperiodism.
Of the five species kept commonly as pets, only the Campbells and Winter Whites are able to interbreed and produce live offspring (hybrids). Hybrids are most often unknowingly produced through incorrect identification of the two similar species of hamsters, and unfortunately the number of hybrids is increasing particularly within pet shops in many countries today where they are often mislabeled as being one or other of the pure species.
Although hybrids make suitable pets, the breeding of hybrids should be avoided as it can cause health and birthing problems, and also the widespread breeding and distribution of hybrids could threaten the existence of both pure species in captivity. Therefore, if intending to breed Russian hamsters it is important to ensure that both hamsters being bred are a pure form of, and of the same, species to avoid producing hybrids.