If you pick it up with an argy, hit it once or twice before dropping it. After it goes through it's heal animation, pick it up and hit it once more. Drop it, tranq it slowly so as to get more heals, and then once it is KOed, put whatever food you want to take with in it's inventory. I KOd one I hit a few times with my argy, and once I put iguanodon kibble in it's inventory it tamed in a matter of seconds, basically meaning one can starve tame daeodon without having to wait, force feed narcos, and then give it food. Happy taming!