These two adolescent bull Rhinos had been friends up until today. But now, they decided it was time to decide who would be the alpha male. The zookeeper wasn't yet aware of the change. The rhinos were really going at it, chasing each other around at surprisingly fast speeds, and battling it out for dominance.
If you look at the larger image, you can see all the wounds and blood on their faces from the battle. I have never seen so much action at the zoo before.
I guess they forgot to tell them that this is just a zoo...
(Whoever said that zoo animals are not wild?!)