Single Kitten Syndrome
Adopting a kitten? Go for two!
If you've ever raised a litter of kittens or adopted a pair of them, you know how much they play together. Some of this play is painful, as confirmed by the yowling and complaining that occurs. The kittens bite and scratch each other, sometimes quite hard. All the while they are learning from one another that this behavior is not the best way to make friends! If they're lucky enough to have a mom cat around and she hears the ruckus, she will often give a warning "that's enough of that" to the kittens and they settle down.