For knocking out you will need at least 65 boulders. I do not know the exact amount so that amount is all guess. And second always aim at their back because hitting the limbs will do massive damage and will possibly kill it. After it is knocked out you should load it with narcotics and carbo kibble, spoiled meat, or raw types of meat. Good luck!
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. UP-VOTE SO EVERYONE KNOWS & TO GET DODODEX TO ADD THIS!!!