One of the best and most efficient ways to tame one is use a large wood signpost or a metal signpost literally one of the best traps I've used get it to by a decent tame that has good health and try to place a bunch of these in front and around it to trap it and back away and it will just sit there and bam rex tamed

If you have enough metal;

Craft 4 metal billboards and one big bear trap.

Place down 3 of the billboards like this I_I and place the trap in the middle. Lure the rex into it, very easy and best to do on feet and then if he gets trapped, place the last billboard to close the cage.

Now you can take your time, knock it out or let it stay in there.

If the rex, somehow, gets nearly dead, I believe you can try to give it some corpses to eat and its HP will go up. :)

- ByNT

Who else thinks the rex should be bigger. Like in real life the giga was only 3 feet taller or so bigger than the rex but in ark it twice it’s size!! Also in real life the rex could easily kill a giga , much unlike ark. In other words the giga should be the short one and the rex should take its rightful place as king of the ark! Also the giga should be around the same size of the rex and the spino and a tamed rex should be able to kill a wild giga

Easy:

make sure you have a getaway, a couple stacks of meat, and a ton of tranq arrows(or darts)

stand on a real tall rock

shoot it to make it come to you (with rifle or crossbow)

once it’s stuck at the bottom of cliff (or rock) shoot it with TRANQ ARROWS(or darts)

repeat until it goes unconscious

get off and place your meat in inv

wait half an hour and you got the most popular apex predator in the dino kingdom

To tame a Rex build a stone trap by placing foundations in a square or rectangle at least 8 by 8 then making 4 walls out of stone door frames 4 high (or you can use standard Dino gate frames for 3 walls, then put the door frames for the 4th wall). Then make a wooden ramp down one side of the trap (the ramp will attach to the top of the door frames). Once you have your little trap with a ramp get the Rex to chase you. Run up the ramp and make sure it’s right behind you, then jump into the trap and run out one of the door frames. The Rex will fall in and not be able to leave. Tranq it out through the open stone door frames or Dino gates from a safe distance away. Catch any level Dino with this trap. Bigger Dino’s need bigger traps.