So friend and I tamed one this morning. Mated my rexes got 4 eggs to about 8% from hatching.(boosted hatch rates). Took the eggs close to where the carchar was, hatched one egg. Killed the rex and my buddy carried it up til it looked at him dropped the body and ran a little bit. Carchar ate the corpse and was ready to be mounted. No cage needed just got to have some massive balls.