At birth, baby dwarf hamsters are about 1 inch long and weigh less than 3 g, with little size variation among species. Three species are found within the genus Phodopus: Campbell's dwarf hamster (P. campbelli), Roborovski's or desert dwarf hamster (P. roborovskii) and the winter white Russian or Djungarian dwarf hamster (P. sungorus). The genus Cricetulus, which is less common in the pet market, contains seven species, including the Chinese striped dwarf hamster (C. barabensis).
Baby dwarf hamsters are born fur-less, but develop a coat similar to adults within the first month. Baby dwarf hamsters can develop several coat colors, including agouti, or gray brown with white belly; argente or tan with white belly; opal -- bluish-grey with white belly; pure black or pure white. Some species can also show darker stripes and marking on their backs. Especially when living in the wild, the Djungarian dwarf hamster replaces its dark fur for a complete white coat when winter approaches. The species, native to the Russian steppes, has developed this winter camouflage to disguise itself in the snow, deceiving predators.
Dwarf hamsters are born blind, and develop poor eyesight which they keep throughout their adult lives. As adults, dwarf hamsters have red or black eyes. As baby dwarf hamsters are fur-less and have transparent skins, it is easy to identify the color of their eyes even during the first week when they keep their eyes closed. Only black eyes are clearly visible through the eyelids. The skin of newborns is so transparent that even the milk in their stomachs is visible after they fed. Despite relying solely on milk during their first two weeks, dwarf hamsters are born with teeth.
Dwarf hamsters from the genus Phodopus learn to be social and live in colonies from the very first stages of their lives. On the other hand, some youngsters from the genus Cricetulus can be more nervous, less sociable and quieter animals. In captivity, Phodopus baby dwarfs generally tolerate the company of individuals from other litters when introduced within the two first months of their lives.