Me and my mate went to Dead Island and encountered one of these; It agroed on us and we shot it with traqs. On the last shot, right as it was about to kill us, it got knocked unconscious and we tamed a 137 Rex.
I once tamed a 131 rex, it came out as a 172. I had tamed it in the redwoods on ragnorock and was riding it back to base when I saw what I thought was a saber tooth in a tree. It pounced me off my rex and killed me. It was level 110. I then learned after loosing my rex (who was on passive) that thylacoleos are no joke.