This, unfortunately, is quite common. Hamsters kill each other and can bite their offspring. This is not the only example where animals that are kept in the same cage show intolerance to their own kind. However, intolerance is it? Who kills, and who eats already quite decent grown-up hamster children? 1
The culprit is a male hamster
Sometimes the direct perpetrators of the death of the young are hamsters-males. If the owners do not guess right after the appearance of the offspring to evict the “daddy” into a separate cage, then there is the risk of losing the children.
The fact is that in the young the male sees competition. At the level of instinct, the hamster understands – while the female is feeding the young, it can not mate. And the female is quite aggressive towards him, while the period of pregnancy and lactation lasts. It is fair to add that the female is aggressive to any hamster, whether it’s another female or older children. For the sake of surviving offspring, and the world in a cage, only mother with cubs should remain in it.
By the way, if the male and female are always together, the female will bring offspring every two weeks, which will greatly weaken it. And yet, if both hamsters are of different sexes, but are relatives, then inbreeding dooms the brood to death. Kids get weak and parents do not leave them any chance of survival. Not the mother, so the father finishes them. Cruelly? Natural selection.