Ok so if you are on mobile, I figured out how to tame them with no violence. I put amarberries in my hotbar guessing that was like have them "out". Started following g this little guy around, and behold, his tame meter started rising!
Lystrosaurus:Easy Taming- Feed Mejoberries when ever it gets hungry.
-Speed:Pretty fast for its weight.
*Most Important for Beginners or others:If u tame a couple of these guys, U will have extra protection, they're big,strong, can keep up with u sometimes- they're very fast for their size and weight!*
1. Do not knock him out.
2. Feed him any berries, mejoberrys are more effective.
3. Don't let him get hungry for long time because the taming % will start dropping, so stay with him and wait until he get hungry again and feed him.