I think they are broken rn. I was taming a 140 put 100 tranq arrows in it with a 218 damage crossbow. And it’s the second one in a row that did that to me. Like after they go into their shell and then come back out they don’t move. They are broken.
Build a 3x3 platform, then build a metal/stone hatchframes on top and put a ramp leading up to them. Build walls up top and lure Doe onto top level. Go below and shoot underside through hatchframes with tranq darts, done
Shoot for the head or tail with trans arrows and crossbow combo. When it rolls into a ball leave the area and keep an eye on them with a spy glass. Wait for it to start moving before approaching and shooting again. For high level ones, use a magnifying glass to check the torpor lvl while it's in ball form. Takes several rounds to get them knocked out. Don't waste your time trying to apply torpor while it's in a ball. Good luck.
I was flying my pteranodon, and i saw a lvl 27 rex pick on one of these lil cuties. He curled up into a ball, and took no damage, so combined with its mining capabilities, this lil guy is perfect for the mountains, as they have incredible defense, and mining capabilities.