Hamsters were kind of grump little souls, when I was just a boy; but it looks like that’s been largely bred out of them and now they’re much friendlier.
So here are kittens trying to make friends with hamsters: nobody taught them they were supposed to eat them. And no one taught the hamsters to be afraid of kittens.
My cats never showed much interest in my mice, beyond a casual sniff or two. It was the baby fence lizards that they wanted to wolf down. But they couldn’t get the lid off the tank.