What is the origin of the idiom "lock horns" and when to use it?

The idiom "lock horns" originated from the literal behavior of certain animals, such as deer or bulls, who engage in combat by clashing their horns together during a territorial dispute or a struggle for dominance. The phrase is now used to convey the idea of a direct and confrontational engagement where both parties are firmly asserting their positions and are unwilling to back down.