Went duh. These are obviously the same beastmen as I am using in another story. Albeit on a different continent for differences in customs and laws. But wizards in this world blended humans with animals in an attempt to make creatures that they wanted. And all that magic floating about obviously made them very prone to be sorcerers.
I don't know if there's a shape-shifting bloodline, but I can roll my own. It is, after all, a homebrew world. (And I've already decided to roll my own for another sorcerer in this story.)
Are beastmen in general prone to be sorcerers, or is this a fluke of what the wizard did here? Hmm. I shall have to ponder that.