Hamsters are known to kill one another and eat the remains (often beginning with the stomach), so it’s a wonder they’re so highly recommended as children’s pets! Maybe parents wanted a short-lived animal to explain life and death and figured they’d just lump “murder” and “infanticide” in there while they were planning life lessons.
I kept my hamster cages stacked because I thought it would be comforting for the babies (that survived) to be near their mother when I moved them out from her cage. What actually happened was the mother broke free from her cage, broke into the juvenile cage, and killed and ate three of them (the screams woke me up and I stumbled in on the middle of it). Two survived by escaping into my apartment and living like house mice.
Out of the two that survived, one was the ultimate winner when it tracked down its surviving sibling and murdered it. I recovered that hamster by catching it eating the remains of its sibling.
Hamsters will go out of their way to kill and eat one another if they can escape from their cages or you try keeping multiple ones together. Do the smart thing and just buy rats. You’ll save yourself years of trauma and they act like small dogs.