Cannibalism is not a pleasant thing to think about, but it sometimes occurs in some small mammals. It is usually associated with new mothers and stressful situations.

Of all the small mammals, the hamster is given the distinction of being the creature most likely to cannibalize her young. Adult hamsters will even attempt to cannibalize each other, under certain circumstances.

Why Cannibalism Occurs

Cannibalism can occur in nature for a variety of reasons. In most small mammals (gerbils, hamsters, rats, mice, rabbits and guinea pigs) cannibalism is most likely to occur when food and water are scarce, and the drive for self-preservation kicks in. After delivering her new litter, the mom may realize that resources are scarce and cannibalize the litter to reduce the number of mouths to feed and water.

Cannibalism may also be used to reduce the size of a litter in very big litters or if it appears that the young are sick or deformed. Cannibalism may help the female return to estrus (heat) in order to become pregnant again and, hopefully, deliver a healthier litter. Other common causes of cannibalism include:

Environmental noise

Housing too many adults together - overcrowding

Handling of the young by a human (if less than 10 days old)

Disturbing a new mother

Leaving the father in the cage after delivery for more than one week after birth

Inadequate nesting material

Lack of privacy

Inappropriate litter size – too many babies or not enough (occurs in rats)

Wire floor caging (primarily in hamsters)

Prevention

Once cannibalism begins, it is difficult to stop the mother from killing and consuming her entire litter. The best thing to do is to make sure she has a stress-free and private environment to deliver and care for your young. Make sure to remove the male from the environment at the time of birth or immediately after. For some species, the male can be removed once the female is pregnant. Other suggestions include:

Do not move the female to a new cage.

Provide a nest box and hiding places.

Make sure there is plenty of food and water available.

Do not handle the mother or babies for at least the first 10 days after delivery. Two weeks is even better.

Do not clean the cage for at least the first week after birth.

Avoid cedar shaving or sawdust bedding.

Make sure that any wire flooring is covered.

Remove dead or deformed babies immediately.

For hamsters, it may help to offer the new mom wheat germ, apples or a meat product.