This will likely need some polishing, but it's something I've been rolling around for a while now. With all of the exotic beasts (mephos, camarie, jhore, windwalkers, earthshapers, even the lesser varieties that can only be used as 'pets'), it only makes sense that there is a relevant skill for training them. Just because you own one, doesn't mean that you know how to tame it, care for it, etc. So, here we go:
Novice: You've seen an exotic beast before and know they exist. Maybe read a little bit about them.
Apprentice: You are familiar enough with exoitc beasts to begin understanding the basic temperament, behavior, and reactions. You can effectively start training them slowly at this point.
Journeyman: This isn't your first rodeo. You have successfully trained at least one exotic beast. Whether for yourself or for someone else. These creatures understand that you are not a threat to them, and will respond to you more than someone with no experience.
Expert: You can work with a variety of creatures. Your experience has given enough knowledge and empathy to be recognized as a paragon in your field.
Master: You are the king of beasts. They will recognize this, and will respond to you. Though this does not interfere with the bonds between Mephos and companion, but you are able give customized training to nearly any creature that's intelligent enough to understand.
Like I said, this might need some polishing, just throwing the idea out there. Also, this could pertain to one exotic beast in particular. I.E. ...Exotic Beast Training - Jhore. Then you can take it for Camarie. Or Mephos, etc. Or it could pertain to all of them in general.
Fire away with feedback.