On crystal isles,these are an easy find in the river that surrounds the biggest yellow crystal at the Eastern floating islands.

Easily at least 8 there at a time. Be sure to look at all the small lakes in the area you can find 2 in each of them at anytime.

Available at floating island caves in Crystal Isles. Uparrow so people know
They're very rare in there so be patient

Tranq Arrows/Darts DO NOT WORK!!! To knock this out you need to use a catapult and shoot in only on it's back. If you shoot it on it's legs it will kill it.
@Stormwebb19

Cannon balls discrease taming effeciency significantly! So for high tame level, always use boulders. Please let other people know! :)

Guide to using Stego(s) as Swords:
1. Put Stego(s) on aggressive.
2. Pick them up using the Crab
3. Walk near target.
4.Enjoy

If Mr. Krabs can pick up stegos, WHY CANT THEY PICK UP TRIKES!!?!??!?!?!?!?!?!?!?!?!?!?!? Pick things up with this, and tranq them with rifle, u can do it while mounted, or, thing u want to tame in one claw, snake in the other. Boo yah! U are welcome.

I understand that all the previous tips submitted were useful, but just in case it was not clear, hit the TOP OF THE CRAB, it will have a special animation if you hit it in the correct spot, and will take only a small amount of boulders to tame, even a high level. (Irrelevant with Cannons)

They spawn in Genesis in several caves in the Lunar biome

Up this if you think they should add the amount of boulders it takes to knock one down⚡️

Jumps super high and can launch stegos ... two at a time RIP turrets lol

If you're taming and its health is low, put a corpse beside it. That should do the trick to heal it

This tame is like the Rock elemental, but do not shoot it in the head. Shoot it right in the back of it's shell. Anywhere else will kill it fast.

Beaver in one claw
Doed in the other
Farm some stone structures

If you are missing with your catapult and it's dying, drag dino corpses to it and let the karkinos eat the corpses. It will heal him up a lot then try again with the same torpor you left off with.

If you're carrying a tamed Doedicurus in your claw the Doedic will automatically start harvesting any stones you hover him over. Just start pumping points into your Doedic's weight because it will stop at about half of its own carry weight. I've yet to discover another tame it will work with though...

Want an effective trap for the crab?
For about 300 stone and wood the youtuber Captain Fatdog will show you the cheapest and most effective trap

It's a Giant crab that can throw it's enemies far away

Be careful when carrying a Dino that has a tribe mate mounted on it. I was walking up a hill carrying my anky with a tribe mate on it and they went under the map and died. RIP ANKY AND SHINEHORN. Tribemate was eh anyway.

Will rip you off tame I repeat TAKE YOU PFF YOUR TAME AND KILL YOU EASY

Using a cannon will ko any level crab in one hit, but will SEVERELY drop taming effeciency. If you want one quick, use cannon. If you want a high level use a catapult (the inferior siege weapon).