In the animal world, if you take rats, who are hardwired to play at a certain period of their juvenile years and you suppress play, they squeak, they wrestle, they pin each other, that's part of their play.
En el mundo animal, si se toman las ratas que tienen programado jugar en un determinado período de su juventud y se reprime el juego - chillar, luchar, sujetarse, que es parte de su juego.