CLASSIFICATION
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Order: Rodentia
Genus:Cricetulus |
The most common species of hamster are the Golden or Syrian hamster, Mesocricetus auratus, the Russian dwarf hamster, Phodopus campbelli and the Siberian hamster (P. sungorus), which is very similar to the previous species; in recent years there has also been a certain spread of P. roborovskii, the Roborovski hamster. The Chinese hamster, initially sold also in Italy but not at all suitable as a pet, has subsequently disappeared from the market.
Until recently it was thought that Russian and Siberian hamsters belonged to the same species, being two varieties or two subspecies. They are now considered two distinct species, although their typical coats make them very difficult to differentiate.
Hamsters are nocturnal animals and dig burrows in the ground. They are fairly easy to keep in captivity, but do require some care each day; they have a very short lifespan and are not, therefore, very suitable as pets for children. They are usually docile, but if necessary can inflict painful bites.
ANATOMICAL AND PHYSIOLOGICAL FEATURES
Hamsters have cheek pouches, which are real bags that they use to transport food (Fig. 1). Indeed the main activity of hamsters is to find food, and in nature they cover considerable distances to do so. The food is then carried into the burrow and stockpiled to make stores for the winter.
All hamsters, like other rodents, have two pairs of incisors that grow continuously throughout the animal’s whole life although they remain a constant length because of the constant attrition to which they are subjected. The internal teeth, unlike those of the guinea-pig and rabbit, have a fixed root and once they have emerged do not grow any longer. The dental formula is I 1/1, C 0/0, P 0/0, M 3/3 (Figs. 2 and 3).
The inguinal canal remains patent so the testicles can always be retracted into the abdomen. The male Golden hamster has very large testicles (the ratio of testicular mass to body weight of this animal is probably the highest of the whole animal kingdom), which must not be confused for tumours.
In nature, hamsters go into hibernation when the temperature drops below 8°C; if the temperature rises, they rapidly become active and it is, therefore, important that they always have some non-perishable food and fresh water available. Hibernating hamsters can mistakenly be thought to be comatose or dead, but this can be excluded by placing them in a warm environment in which they rapidly become active again.
Hamsters are omnivores and feed on a broad range of foodstuffs: seeds, vegetables, insects and any other edible products they find in their environment. Like rabbits, hamsters are coprophages (feeding in part on their faeces) and eat their own faeces directly from the anus; this enables the animal to recover many nutrients to integrate a diet that can, in nature, sometimes be very poor.
