They spawn near the river of green obelisk

They are aggressive toward basically every other wild tame. They are very easily distracted. Be careful near them, they can turn and trap you under them so easily. This is also risky when taming.

They also have "hardened" and melee weapons are basically useless against them.

there is a bug with their spawning, so they instead spawn where sarcos do at 1/10 of the rate

They spawn everywhere that sarcos spawn, this includes some of the caves on the Island!