Signs of aggression

Hello,

I enjoy learning about animal behavior.



Each animal has their own unique way of communicating with one another, I was just wondering if someone could provide a list of signs of aggression as I plan to place two chins together I would like to make sure I don't look over any possible signs of aggression.



For example, you can tell if a horse is angry if they pin their ears back. Dogs if their fur is raised or teeth bared or certain stances, certain ways they hold their tail, etc.



I already know some like biting or aggressive. Also, they will both be males so any male specific aggression signs?



Thanks!