Why do rats go cannibilistic?

Answer 1

Mothers tend to kill deformed or wounded infants, which may allow her to allocate resources to the healthy pups who are more likely to survive. Mothers may also kill entire litters when they are stressed, perhaps because the mother perceives the environment as too hostile for pup survival, or she perceives herself as unable to rear the litter successfully, so she recuperates some her energetic investment by consuming the young. Malnourished mothers, and mothers who have an abnormal birth experience, may also become infanticidal. Read more: http://www.ratbehavior.org/infanticide.htm