Nature
Hamsters are small rodent species, that have gained popularity as house pets (1, 2). Several different types of hamster species are found, with the popular ones being Mesocricetus auratus (Golden/Syrian hamster), and the two varieties of Phodopus species i.e. Phodopus sungorus (Djungarian Siberian dwarf hamster), and Phodopus roborovskii (Roborovski hamster) (1, 3). Cricetus cricetus (European/common hamster) is another variety of hamster species, however, it is less known as a house pet (2).
Hamsters are typically characterized as species with huge internal cheek pouches, dense bodies, short tails and legs. The color of a hamster’s hair coat varies from white to grey, cream, albino, piebald and cinnamon. Further, males possess distinct flank glands and huge testicles, protruding at the back, on either side of the tail and weigh less than females (4, 5).
Regarding characteristic features of individual hamster species, the adult Golden/Syrian variety measures about 14 to 19 cm in length and around 110 to 140 g in weight (5). It is reddish-gold in color along the dorsum, whereas greyish-white underside (4). It possesses sharp-pointed, dark-colored ears with tiny, bright eyes (5). The Djungarian hamsters include Siberian (Phodopus sungorus) and Russian (Phodopus campbelli) dwarf hamsters, that measure about 50-100 mm in length, with tail measuring about 10 mm and body weight around 18-25 g. The body fur is grey colored with dark stripes running dorsally alongside the whole body, while the underside is white in color (5).
Habitat
Hamsters are found in different habitats in the wild. The Golden hamsters are often seen in dry and temperate regions. In native surroundings, they prefer deep burrows that have cooler conditions and greater humidity compared to the desert environments (5). Siberian hamsters live in extremely dry and continental conditions with sharp differences in temperature, ranging between -45oC (winter) and 30oC (summer). Due to varied temperature variations, these hamsters hibernate during winters to save energy (6).
Although hamsters are considered as rodent species, they are still kept as pets in enclosed spaces and are generally not regarded as pests (7). Besides, hamsters can also adapt well to other environmental conditions, like housing, agricultural farming, and laboratory settings (8).
Taxonomy
Hamsters, similar to rats and mouse are rodent species that belong to the order Rodentia and suborder Myomorpha. More than 24 varieties of hamsters are found across the globe, with the Golden species, followed by the European one being most widely used for laboratory testing (4).
| Taxonomic tree of Hamster (9) |
|---|
| Domain |
Eukaryota |
| Kingdom |
Metazoa |
| Phylum |
Chordata |
| Subphylum |
Vertebrata |
| Class |
Mammalia |
| Family |
Cricetidae |
| Genus |
Cricetus, Mesocricetus, Phodopus |
| Species |
C. cricetus, M. auratus, P. sungorus / campbelli and roborovskii |
| Taxonomic tree of Hamster (9) |
|---|
Tissue
Allergens in the animals are generally produced by the secretory glands and are then distributed into the body fluids (such as saliva, urine, sweat, milk, and blood) and skin of these animals (10). Continuous shedding of the allergenic protein molecules occurs through secretion, urine, and skin peeling. Further, allergens may also be present in the environment or may get accumulated on the laboratory instruments and materials, which in turn could lead to the development of allergies (11).
In the case of rodents, such as hamsters, mice, gerbils, and rats, the primary source of exposure to allergens is through urine, which is followed by epithelium, saliva, fur, dander, and hair (2, 10, 12, 13). The major allergen of the Siberian hamster (Phos d 1) has been derived from the epithelium, fur, salivary glands, and urine (2, 14), whereas in case of the Golden/Syrian hamster (Mes a 1), it is reported to be present in the submaxillary glands of the male (3).
