Did you know that certain species of ants keep slaves?
The Red Amazon ants have large piercing mandables designed for a life of fighting. They are useless for hunting, foraging, or raising their broods, so the only way they can survive is to raid a neighboring ant's nest and steal their larvae which get sprayed with a special pheremone that has a similar effect to the way humans brand other humans.
And then there's termites...
YouTube - Termites - Life's Ultimate Architects