Yeah these ones are good for protection and carrying load... So want to tame it, I'll tell you so :

First u need tanq arrows or darts atleast carry 30,prime meat (raw) or meat(raw) to feed it and a long neck rifle to shoot.

Second shoot darts or tranq arrows to rex u want to tame and shoot until it falls down unconscious.

Third feed it raw prime meat, it will give 15%taming at once or raw meat which gives approximately 5%of taming

Fourth wait for taming and now u got a rex. 🙌

^ for this tip if u find it useful and also one ^ = one like to my rex which I named as rexy.