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...