If you try to register it at a stable, they tell you they can't because they're scared it'll eat other horses lol
You can only mount him to stab him, if you look at the UI soothe isn't an option. And as a side note, there are several things you can't ride sadly. Like those bull things.I noticed yesterday while fighting properly and for the first time a Lynel, and saw that when you stun him, you can mount him.
However, I'm not sure if I can actually tame him or not since I don't have enough stamina.
Can anyone confirm if you can tame one? Or is the mount option there just to attack him?