If your a dumbbell like me, this is what will happen. So you see a big blue egg next to a brontosaurus, and you realize your hungry, so u grab the egg and run back to your giga. You better be a fast runner, I figured that out the hard way.
Finally tamed, tried all different traps but main thing is to let the crab eat you if its health is too low and come back to pounce on him again. You wont lose too much torpor and he will get about 30% of its health
Ankylos are not useless even in the wild. If you're being chased by a carnivore, run to them. They are very strong depending on its level. And they usually spawn on groups, which means they can kill anything easily.
Don't even need a trap. Just make sure the area is safe then tranq it. These guys are slow, so just don't be so next to them and you'll be fine. After knocked out, you'd better want a strong dino to protect it, because Ankylos take long to tame without kibble. And that's it, you'll have one of the best farmers of the game, very easy tame