You can tame these guys. But you can't bring them back with you to The Island. And you need to cheat. This will not effect achievement or ascend process. To tame, bring up admin menu. (Look online if you don't know how.) the type, "forcetame" while looking at one. It will be tamed and rideable. Your not supposed to tame them though. So there might be bugs. Also. Don't tame the final boss. You will be unable to kill it and the fight will pretty much be worth nothing.
Hope this helped.
(P.S. if you're okay with breaking the game and not being able to end the fight. You can forcetame the boss. It is rideable and can attack. You can't bring it back to The Island.