I would say to build a 9x9 stone platform with a one lvl of wall and place it near your base then go and find a high lvl rex with your rhynionatha since it can carry rexes then pick him and bring him to your base drop him In the platform you made he won't be able to do anything and you can easily knock it out ( if rex is hitting your rhynionatha midair try to fly diagonally this will prevent rex from hitting you)

If you’re like me and don’t have anky’s or dodek’s to grind for materials, just get your movement speed up to 145%. This allows you to outrun them easily. Also, I play on 0.5 difficulty, so the max level of creatures that spawn is 60. I also have taming rates doubled. Just run away from the rex and periodically turn around and shoot it. I like to do this on the east side of the island by the big mountain. That way the beach is fairly safe and there is lots of room for the rex to start torpor running. The water usually isn’t a big problem. I just tamed two rexes this way!

You shouldn't really need a trap or alot of tranq they are pretty hard to miss head shot or miss and if you have bumped your movement a little you can easily out run a wild rex get distance fire a few tranq run shoot etc... it's torpor is so slow even if you leave for a few minutes to make a new bow or narc. It shouldn't matter at all super easy and able to do on foot by the time you can make tranq arrows

relatively easy trap: 4 stone floors going in a box or square shape, then 2 stone doorframes high placed on top of the floors, leaving no spaces behind (16 doorframes), then two wooden ramps placed on any side of the doorframes. next, lead the Rex inside the trap and escape using the open doorframes. I recommend prime meat (will usually take narcotics, but I prefer biotoxin to keep them sleeping) or the kibble needed for the Rex.

please don’t challenge a giga with a Rex.

Step 1:raged all day look of one

Step 2:have a shot 100 tranquilizeing darts

Step 3:take the lives of land animals

Step 4: feed the Rex the Rew meat and if it going to wake up give it narcotics.

Step 5: have a good friend to make you a Rex satled.

And if you not find cry your self to sleep

I tamed one at lvl 45 and its really easy

Step 1:

Get biotoxin (preferably) or narcotics, maybe also narcoberries

Step 2: Get raw meat, prime meat, or mutton

Step 3: Get a bow, crossbow, or longneck.

Tranq arrows for bow and crossbow, tranq darts for longneck or other rifles

Step 4: Find rex

Step 5: Get on rock and bring and shoot (bring a fast or flying tame just in case, its optional)

Step 6: Once it’s knocked out, feed it the meat that I preferred

Step 7: Feed it, wait, and feed it toxins or narcotics when unconscious level is low

Step 8: Wait.

Step 9: Once you have tamed it, congrats! You have one of the most powerful non-boss creatures!

Extra: It’s saddle unlocks at lvl 74

If you ever find and want to fight a alpha rex here’s 3 steps that help a lot

1. Lead it to a large body of water (note check for jellyfish before doing this)

2. Spray it down with wyverns until it starts to get bloody (note watch you stamina and also make sure that you don’t get hit and lead it out of water)

3. Find a hill too with a flat rock and spray it down (note when they retreat let it because it might be glitched trying to eat and dead carcass)

Also note that blood wyverns are the best for killing these!