Tip: if you feel like rex in dangerous area or scary to fight huge area full with dinosaur, i recommand kill it, and take A green thing in his invteroy in any obisk red or green beacuse it both great spot to spawn it, Also make hanger in it, so you could sleep him by using tranq, once you make Nice size hanger on it, reaviel him and sleep him,

Note: You need amber depend on how much Level dino..

Game verison i did it: Ark Mobile

Hopeful It did help