Hamsters are small, virtually tailless, velvet- furred rodents with enormous cheek pouches. They originated in the Middle East and southeastern Europe. The most common and popular, both as pets and laboratory animals, is the golden or Syrian hamster. Color and hair-type varieties of the golden hamster include cinnamon, cream, white, and “teddy bear” (the long-haired variety). Most of the hamsters sold as pets or used in research are the descendants of 3 littermates domesticated in 1930.

The cheek pouches are a relatively unique anatomic feature of hamsters. They are actually a cavernous outpouching of the oral (mouth) cavity on both sides, extending alongside the head and neck to the shoulders. These pouches are used to store food and allow the hamster to transport food from where it is gathered to the hamster’s den or nest. The food is then eaten later, at the hamster’s leisure. Hamster owners not familiar with these cheek pouches often panic when seeing them fully distended for the first time, thinking they represent tumors or abscesses.

Another relatively unique anatomic feature of hamsters is the paired glands in the skin over the flanks. These appear as dark spots within the haircoat and are much more obvious in males than females. These glands are used to mark a hamster’s territory and also have a role in sexual behavior.

Hamsters are very popular pets today because of their avail-ability, affordability, small size, cuddly appearance, often docile temperament and relatively clean habits. They are not very long- lived, which can be disconcerting to owners (especially children). Many parents, however, believe that having their children experience the relatively short period of companionship and subsequent death is a meaningful way to expose children to the “ups and downs” of life.

For many years hamsters have been used in biomedical research laboratories. Consequently, their medical problems have been traditionally approached on a group basis, rather than on an individual basis. As a result, very little practical information exists on the medical care of individual hamsters. Furthermore, even less information is available to pet owners on the responsible home care of hamsters and their potential medical problems.

FOOD AND WATER:

Good-quality food and fresh, clean water must be readily available at all times. The exact nutritional requirements of the hamster are not known. In the wild, they are omnivorous, feeding on plants, seeds, fruits and insects. Pet hamsters are best fed commercial rat or mouse diets containing at least 16% crude protein. These foods are usually available as dry blocks or pellets.

These commercial diets can be supplemented with small amounts of dry, sugar-free breakfast cereals, whole-wheat bread, uncooked pasta, cooked chicken, tuna fish, cheese, fresh fruits (apples) and vegetables. The last 2 items must be thoroughly washed to avoid exposing pet hamsters to pesticide residues and possible bacterial contamination.

Pet stores sell prepared hamster diets available in boxes or bags. These diets contain large quantities of seeds and items rich in oils. Consequently, if improperly stored, they become rancid and lose their nutritive value. Furthermore, these oil-rich items promote obesity. These types of foods can be offered as a supplement to the commercial rat or mouse diets mentioned above.

All food should be provided in heavy ceramic crocks that resist tipping. The sides of the crocks should be high enough to keep bedding and fecal material out of the food, or the crocks should be elevated slightly above the bedding.

Water is most easily made available and kept free from contamination by providing it in one or more water bottles equipped with “sipper” tubes. Make certain the end of the tubes are positioned low enough to allow all residents within the enclosure (especially juvenile hamsters over 1 week old) easy access to them.

Also make certain that very young hamsters are strong enough to obtain water from these sipper tubes.

HANDLING AND RESTRAINT:

Hamsters handled frequently from a very young age usually remain docile and rarely bite. Those with docile temperaments and a history of not biting can simply be picked up by using one or both hands, and then held in both hands or in one hand held against the body.

Many hamsters develop untrustworthy personalities and begin to bite because they have been handled roughly or suddenly disturbed or awakened. Hamsters whose personalities are not well known must always be approached cautiously. A glove or small towel can be used to pick up these hamster, or the animals can be encouraged to crawl into a small container, which is then removed from their enclosure.

Unknown hamsters and those known to bite can also be picked up and restrained by grasping a large amount of skin behind the head. As much skin as possible should be grasped between the thumb and index and middle fingers because their skin is so very loose. In fact, hamsters can literally turn nearly all the way around within their skins and bite a handler if this caution is not heeded!

HOUSING:

Proper housing is a major factor in maintaining healthy hamsters. The psycho-social well-being of the pets must be a primary consideration. Hamsters can be housed within enclosures made of wire, stainless steel, durable plastic or glass. The last 3 materials are preferred because they resist corrosion. Wood and similar materials should not be used to construct enclosures because they are difficult to clean and cannot withstand the destructive gnawing of rodents.

Many pet stores sell durable colored plastic enclosures that include attached horizontal and vertical tubes through which the hamster can crawl for exercise. These are suitable enclosures for hamsters. The enclosure must be built so the hamsters cannot escape. This is an especially important consideration because hamsters are proficient “escape artists”. In fact, once free of their enclosure, they are very difficult to find and rarely return to it. A hamster free to roam the house is a real liability because it will chew and gnaw on electrical and telephone cords, and household furnishings.

Hamsters seem to do best when housed in enclosures with solid floors, relatively deep bedding, and abundant nesting material. The enclosure should be easy to clean, well lighted, and adequately ventilated (see Vital Statistics for preferred temperature and relative humidity ranges).

Bedding must be clean, nontoxic, absorbent, relatively dust-free and easy to replace. Shredded paper, wood shavings, and processed corn cob are preferred bedding materials. Cotton or shredded tissue paper (Kleenex) is suitable nesting material. We do not like cedar bedding for several reasons. It masks odors, giving a false sense of security that the cage is clean. As a result, the environment will become toxic and contaminated with bacteria.

Hamsters are primarily nocturnal (night-active) though they may exhibit relatively short periods of activity throughout the day. During their active period, hamsters eat and exercise. Hamsters seem to especially enjoy exercise wheels and other activities.

The plastic enclosures equipped with horizontal and vertical tubes/tunnels mentioned above are highly recommended for this reason. Hamsters seem to really enjoy running through them. They also enjoy tin cans opened at both ends and boxes with multiple openings through which they can crawl.

Pet hamsters are usually housed singly. Sexually mature females must not be housed together because of their inevitable aggressive- ness toward each other. Breeding females are larger than males and tend to be aggressive toward them. For this reason, males must be removed from the enclosure after breeding has been completed.

HYGIENE:

The frequency with which the enclosure is cleaned depends on its design, the materials out of which it is made, and the number of hamsters within it. As a general rule of thumb, the enclosure and all cage “furniture” should be cleaned and disinfected once weekly.

The food and water containers should be cleaned and disinfected once daily. More than one set of containers should be maintained, and the soiled set should be washed in a dishwasher, if possible.

Vigorous scrubbing of the enclosure and furniture with hot water and soap and a thorough rinse should be followed by use of a disinfectant (Roccal-D: Winthrop or a chlorhexaderm solution).

HUMAN ALLERGIES TO HAMSTER DANDER:

Certain people are allergic to the hair and/or dander of hamsters. People working with hamsters in laboratory situations are more likely to develop such allergies because of their continual association with them. Signs include itchy eyes, sneezing, runny nose, persistent cough, shortness of breath, wheezing, a skin rash, and anaphylactic shock (a true medical emergency).

Owners of pet hamsters may also be susceptible, and a medical doctor should be consulted about suspected allergy problems if a hamster is kept as a pet in the household. Hamster owners with such a suspected allergy may want to consult an allergist.

VITAL STATISTICS:

Scientific name: Mesocricetus auratus

Potential Life span: 2-3 years Adult body weight: 100-150 grams (Adult females are slightly larger than adult males)

Desirable environmental temperature: 65-70 F

Desirable relative humidity: 30-70%

Recommended age at first breeding: male: 10-14 weeks female: 6-10 weeks

Length of estrous (heat) cycle: 94 hours

Gestation (pregnancy):15-16 days

Average litter size :5-10 young

Age at weaning: 3 weeks