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Health Care for Hamsters
General Information
Hamsters are small, virtually tail-less,
velvet-furred rodents, possessing enormous cheek pouches.
They originated in the Middle East and Southeastern
Europe. The most common and popular, both as a pet and as
a laboratory animal, is the golden or Syrian hamster. A
number of color and hair-type varieties of the golden
hamster exist including cinnamon, cream, white and
"teddy bear" (the long-haired variety). An
interesting fact is that the majority of the hamsters
sold as pets or used in research are the descendents of
three litter mates that survived capture and
domestication in 1930. The cheek pouches are a relatively unique
anatomic feature of the hamster. They are actually a
cavernous out-pouching of the oral (mouth) cavity on both
sides, extending along side the head and neck to the
shoulders. The function of these pouches is for food
storage and to allow the hamster to transport food from
the point at which it is gathered to the hamster's den or
nest, into which the cheek pouches are emptied. The food
is then eaten at the hamster's leisure. Hamster owners
not familiar with these cheek pouches, and seeing them
fully distended for the first time often panic, thinking
they represent tumors or abscesses. Another relatively unique anatomic feature
of the hamster is the presence of paired glands within
the skin over the flanks. These appear as dark spots
within the hair coat and are much more obvious in males
than females. These glands are used by hamsters to mark
their territory and have a role in sexual behavior. Hamsters are extremely popular pets today
because of their availability and affordability, their
small size and cuddlesome appearance, their sometimes
docile temperaments, and because of their relatively
clean habits. They are not terribly long-lived which can
be disconcerting to owners (especially children). Many
parents feel that having their children experience the
relatively short period of companionship and subsequent
death is a favorable and meaningful way to expose
children to the "ups and downs" of life. Handling-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 with one held against the body. Many hamsters have pugnacious and
untrustworthy personalities, often resulting from a
history of rough handling or being suddenly disturbed or
awakened. Hamsters whose personalities are not fully know
must always be approached cautiously. A glove or small
towel can be used to pick up these hamsters or they can
be encouraged to crawl into a small container and be
removed from their enclosure in this fashion.
Untrustworthy hamsters and those known to bite can also
be picked up and restrained by grasping a large amount of
skin behind the head. It is imperative that as large an
amount of skin as possible 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, adequate housing is a major factor
in the maintenance of healthy hamster. Hamsters can be
housed within enclosures made of wire, stainless steel,
durable plastic or glass. The latter three materials are
preferred because they resist corrosion. Wood and similar
materials must not be included in the construction
of enclosures because they are difficult to clean and
these materials cannot withstand the destructive gnawing
of the occupant(s). Many pet stores sell durable colored
plastic enclosures which include attached horizontal and
vertical tubes through which the resident hamster can
crawl for exercise. These are very suitable enclosures
for hamsters. The construction and design of the
enclosure must ensure that the resident 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 with
"free-roam" of the house is a real liability
because it will chew and gnaw on electrical and telephone
cords and household furnishings. The enclosure must also
be free of sharp edges and other potential hazards. The enclosure must be roomy enough to
allow the resident(s) to pursue normal activities and
breeding activity, if the latter is desired. One
reference recommends at least 2- square inches of floor
area per hamster and a cage height of at least 6 inches. Hamsters are primarily nocturnal
(night-active) although they may exhibit relatively short
periods of activity throughout the day. During their
active period, hamsters will eat and exercise. Hamsters
seem to especially enjoy exercise wheels and other means
by which they can exert themselves. The plastic
enclosures equipped with horizontal and vertical
tubes/tunnels mentioned above are very popular and 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 aggressiveness towards each
other. Breeding females are larger than males and tend to
be aggressive towards them. For this reason, males must
be removed from the enclosure as soon as breeding has
been completed. Hygiene
The frequency with which the enclosure is
cleaned will depend on its design, the materials out of
which it is made, and the number of hamsters that reside
within it. As a general rule of thumb, the enclosure and
all cage "furniture" must be cleaned and
disinfected once weekly. The food and water containers
must receive cleaning and disinfection once daily. We
suggest that more than one set of containers be
maintained and the "used" set be washed in a
dishwasher, if possible. A vigorous scrubbing of the
enclosure and "furniture" with hot water and
soap and a thorough rinse must be followed by the use of
a disinfectant. 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,
fruit and insects. Pet hamsters are most nutritiously and
most conveniently fed commercial rat or mouse diets
containing at least 16 percent crude protein. These foods
are usually processed as dry blocks or pellets. These
commercial diets can be supplemented with small amounts
of dry, sugarless breakfast cereals, whole wheat bread,
uncooked pasta, cooked chicken, tuna fish, cheese, fresh
fruits and vegetables. The latter two items must be
thorough washed to avoid exposing pet hamsters to
pesticide residues and possible bacterial contamination. Pet stores sell prepared hamster diets
that either are made available to box or bag form. These
diets contain large quantities of seeds and items rich in
oils. Consequently, if improperly stored, these items
become easily rancid (the potency of may other nutrients
is often compromised as well). Furthermore, these
oil-rich items promote obesity among pet hamsters. These
types of foods can be offered as a supplement to the
commercial rat or mouse diets mentioned above. All foods must be provided in heavy
ceramic crocks that resist tipping over. The crocks must
possess high enough sides to keep bedding and fecal
material out of the food or the crocks must 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 that the ends of the tubes are
positioned low enough to allow all residents within the
enclosure (especially juvenile hamsters over one week
old) easy access to them. Furthermore, it is essential to
make certain that very young hamsters are strong enough
to obtain water from these sipper tubes. Breeding Considerations
The sex of adult hamsters is easy to
determine because males possess very large, prominent
testicles. In fact, owners unaccustomed to seeing them
are often astonished at and confused about these apparent
anatomic peculiarities. Male golden hamsters must be first bred
when they are between 10 and 14 weeks old. Females should
be first bred when they are six to 10 weeks old. As the
mature female approaches the time of copulation, one will
notice a think, stringy, cob-web like mucus coming from
her vulva. The female is then placed into the male's cage
about one hour before dark. The pair must then be
carefully observed for mating activity or fighting.
Females can be very aggressive to males in this situation
and can cause them great harm. The male must be removed
at once if fighting ensues. Because fighting is such a
likely outcome, aggressive males are most suitable for
hand-mating programs. They are better able to defend
themselves and "hold their ground." The male
must be removed after successful mating has taken place. Pregnancy is of very short duration: 15½
to 16 days. Before delivery, the female becomes restless
and will usually discharge a small amount of blood from
her vulva. Litters usually range from five to 10 pups.
The pups are born hairless and with both ears and eyes
closed. They do possess their very front teeth (the
incisors). Female hamsters with young must be
provided with abundant nesting and bedding materials and
plenty of accessible food and water, and must not be
disturbed in any way. The young should not be touched or
handled until they are at least 7 days old, the nest
should not be disturbed, and the cage should not be
cleaned during this period. Failure to heed this caution
(especially with females nursing their first litters)
most often results in cannibalism of the young. An interesting maternal rearing activity
may be noted by particularly observant hamster owners,
especially if the female with young is excited or
disturbed. She will stuff pups into her cheek pouches and
deposit them into the nest a short time later when she
believes the danger has passed. Occasionally, pups will
suffocate as a result of this activity, especially if the
disturbance for which they are being
"sheltered" is lengthy. Young hamsters usually begin eating solid
food at 7 to 10 days of age but are usually weaned at
about 3 weeks of age. It is most important that solid,
pelleted food be soaked and softened and be placed on or
near floor level of the enclosure for easy access by the
weanlings. As mentioned above, sipper tubes must be
positioned low enough that the smallest of the pups can
reach them. Some pups will not be strong enough to
extract water from sipper tubes, so owners must be
vigilant for this potential problem and provide an
alternative water source for them. Disease
Sick hamsters often become irritable and
frequently bite. They are usually reluctant to move about
and walk stiffly when forced to do so. Their eyes often
look dull and sunken and frequently exhibit a discharge.
Sick hamsters often stop eating or greatly reduce their
intake of food. Consequently, weight loss is a common
symptom (not necessarily an easy one to recognize) of
illness in hamsters. Marked weight loss also may result
from excessive fluid losses resulting from diarrhea.
Sudden onset of intestinal disease (with accompanying
diarrhea) is the most common illness of hamsters,
especially among those that are in the process of weaning
or those that have recently been weaned. The serious
dehydration that often results must be recognized
immediately and corrected with appropriate fluid therapy
at the direction of a veterinarian or death is probable. Wet Tail
The most serious intestinal disease of
hamsters is "wet tail". The bacterium suspected
of causing this disease is called Campylobacter sp. which
is also capable of causing equally serious intestinal
disease syndromes in swine, dogs, ferrets, primates, as
well as other animal species. This disease most often afflicts hamsters
of weaning age (3-6 weeks) but hamsters of all ages are
susceptible. Since weaning hamsters and those slightly
older are commonly sold in pet stores, wet tail is a
fairly common disease among recently acquired hamsters.
The long-haired "teddy bear" hamsters are
highly susceptible to wet tail. Symptoms include
lethargy, inappetence, unkempt hair coat, sunken, dull
eyes, increased irritability, hunched posture, very
fluidly diarrhea, and a wet soiled anal area and tail.
Blood from the rectum and a protrusion of the rectal
lining (prolapse) may be noted in particularly serious
cases. Hamsters suffering from wet tail must be
examined and evaluated by a veterinarian immediately.
Fluid replacement, oral anti-diarrheal medication and
antibiotics will be administered to the patient.
Supportive care must include keeping the patient warm,
clean, comfortable and well nourished. Treatment is often
unrewarding and death often ensures as soon as 48 hours
after the onset of initial symptoms. This disease is not
known to be transmissible to man. Salmonella
Several species of the bacterium,
Salmonella, are capable of causing serious intestinal
disease (salmonellosis) in hamsters under certain
circumstances. The reason why this problem is discussed
in this handout is that salmonellosis is transmissible to
and equally serious in man. The bacterium is usually acquired by the
ingestion of food contaminated with feces containing the
organism. Pet hamsters established in homes would most
likely become infected via this route. It is because of
this fact that fresh fruits and vegetables must be
thoroughly washed before they are offered to hamsters.
Newly purchased pet hamsters may harbor this salmonella
organism, having acquired it from the colony into which
they were born. Salmonellosis in hamsters may manifest
itself as a sudden onset illness with death usually
resulting or as a more long-standing disease resulting in
general debility and weight loss. Diagnosis of salmonellosis requires a
veterinarian to conduct a stool culture. Antibiotic
treatment of the disease may or may not be recommended by
the veterinarian depending upon the public health
implications. Euthanasia (putting the patient to sleep)
would be recommended in the event that treatment is not
undertaken. Rabies
Rabies will be discussed only briefly
because the subject of possible transmission of the
rabies virus to humans inevitable comes up whenever an
individual is bitten by a hamster and because hamster
bites are so common. Hamsters are not natural hosts of
this virus. Therefore, the only way that a hamster could,
itself, become infected with the rabies virus is to
become exposed to infected saliva from a natural host of
the virus (skunk, fox, bat). This is highly unlikely and
improbable for hamsters since they are almost exclusively
indoor pets.
Lymphocytic Chorlomeningitis (LCM)
This viral disease must be discussed
briefly because it can be transmitted from hamsters to
humans. In fact, a large number of such cases were
reported in 1974 and 1975, all of which were traced to a
common infected colony. Symptoms of this disease in
humans include persistent, intermittent fever, headache,
fatigue, muscle aches and pains, sore throat, rash and
arthritis. The natural host in the wild for the LCM
virus is the rodent population and hamsters would most
likely acquire their infection from this source. Because
hamsters are almost exclusively indoor pets, the
likelihood of them becoming infected with LCM virus is
very small. Hamster owners must restrict contact between
their pets and wild rodents that may have been orphaned
in the wild and subsequently adopted. Demodectic Mange (Demodecosis)
Demodectic mange is a common external
parasite problem of hamsters caused by mites which reside
within the hair follicles and certain glands of the skin.
Their presence in this location causes dry, scaly skin
and significant hair loss, especially over the back. This disease is rarely a problem by
itself. In fact, demodectic mange of hamsters if
frequently associated with long-standing, debilitating
diseases (especially those involving the kidney[s]) of
other causes. Hamsters exhibiting hair loss must be
examined and evaluated by a veterinarian as soon as
possible. The doctor will need to do a skin scraping and
examine it under the microscope. The presence of mites in
the scraping confirms the diagnosis. Treatment for this
disease is possible but hamster owners must be aware that
the patient could very well possess an underlying disease
problem for which there is no practical treatment or
cure. Intestinal Parasites
Hamsters frequently harbor tapeworms
within their small intestines. Heavy infections may cause
weight loss. Lighter infections usually go undetected
unless pieces of the worm pass out of the hamster's
rectum or appear in the feces. This parasitism is important to discuss
because people can become infected with the same
organism. Transmission of tapeworms to uninfected
hamsters (or humans) occurs when feces harboring tapeworm
eggs are inadvertently ingested. This underscores the
importance of restricting access to hamsters and their
enclosures by very young children. All encounters between
them must be carefully monitored. Hamster owners suspicious of this parasite
problem must submit a fecal sample to a veterinarian for
analysis. Presence of tapeworm eggs in the sample (noted
microscopically) confirms the diagnosis. Treatment is
possible and will be instituted at the direction of the
veterinarian. Pinworms cause a less frequently diagnosed
intestinal parasitism of hamsters. These extremely tiny
worms reside within the large intestines and usually
cause no symptoms at all. Diagnosis will be made by a veterinarian
after microscopic examination of the feces from a hamster
suspected of harboring these parasites. Sometimes pinworm
eggs pass from the rectum of the hamster causing intense
itching in this area. A veterinarian may be able to
detect the presence of pinworm eggs by pressing
cellophane tape to this area and examining it under the
microscope. Pinworms of hamsters do not case disease in
humans.
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