Well I know it's not the triangle button as that killed my pet alpha wolf today. Why Assassinate & Interact are the same button I don't know. Also, Alpha SHARKS are a thing. No, we can't tame themstand right next to the animal and wait a couple of seconds. Then push the "Y" button on the Xbox controller. You pet your animal. I don't know what the action is for PS4 or PC.
If you don't have a tamed pet, you can stand somewhere for a couple of seconds and your eagle will perch on your arm. Then you can use the same command to feed him or pet him too.
I want to ask: those who killed Daphnae at the end of the Legendary Creature questpath, did all Daughters of Artemis become friendly? Do you actually become leader of the Daughters? I couldn't do it since she was one of the few NPCs you get to interact with for a long time. That and continual nookie