Troodon Tamara beware, I am currently encountering an issue where any rexs being used for taming troodons won't actually be unconscious. Tranqued rexs will still attack the troodon you are trying to tame!
At lvl 72 with flak armor on, a lvl 5 Troodon knocked me out with one attack at night. Last thing I saw was those glowing eyes before passing out. My Guess is that they attack vital organs. Luckily my Doedicarus was up for a game of baseball and launched that little devil out into the stands.
Went to go grab a drop during the night on my dragon. I was wearing full Master Craft Flak Gear and two bites from these little sneaky bitches and I passed out. Luckily my dragon was on nuetral. Unluckily that it's fire breath roasted me too. Lesson learned:
Burn everything on fire before you get off your mount...