This is a little expensive but, I tamed one in a box by tranqin it when it woke it was calm and I was able to follow it around the box and pet it. Hope this helps

Normally you can't tame the pack leader, so just get a pteranodon or argy, pick it up and drop it in a large area (like a separate section of your base). When you take it away from the rest of the pack, it removes its 'pack leader' title, allowing you to tame the highest level hyena of that pack.

Despite it's appearance, the real life hyaenodon was nowhere near related to actual hyenas, but it actually belongs to a group of prehistoric mammals, all extinct, that are believed to be most closely related to pangolins, which aren't related to anteaters or armadillos, for your information.

Build a 1x1 box with door frames and throw a hatch ceiling and 4 more regular walls up and throw it in, it's butt will hang down and you can crouch and pet it under it without spooking it. You CAN tame without alpha present but if it becomes spooked you have to leave your chunk and let it reset.

Basically follow them around and when there parents aren't looking pet them