Ceratopsian Sparring
The ability to approach another ceratopsian and press an interact key, inviting the other player to spar. If they accept, an animation plays, and your dinosaurs lock heads. A button clicking mini game appears, and the first person to push the bar fully to their side wins. (Perhaps giving the winner a “dominant” buff)
This would mostly be a pastime, but on realism servers could be used to dispute territories or food sources.