When I tried to tame one of these, there was a lot of saber tooths in the area, so as soon as I knocked it out, I was killed immediately, but for some reason, they left the anky alone. Sometime later, it said i have tamed an ankylosaurus, so I was poker face for 2 seconds while trying to remember,but not for long (3 ½ minutes[which is pretty long]) it came running at me with (of course) a pack of saber tooths behind it. It killed at least 3 before I died. Then the game crashed and I lost my anky.