If you play on mobile and want to do the roll then go to settings left or right multi tap and chose alt attack 2 !!!
NOW FOR THE MAIN PART--- THESE THINGS CAN KILL GIGAS the normal roll does decent damage but if you roll and attack a dino while watching the dino through spyglass you can deal tons of damage (this works in mobile idk about other platforms) i killed tons of rexes,brontos,allos..etc. using this trick
How to do barrel roll on mobile: Go to settings and then go to controls then either go to left multi tap or right multi tap. Then select Reload/Alt attack2. When you are done, go and press on your screen twice on either left or ritght side. And you pteranodon can now do a barrel roll! Disclaimer:wastes stamina alot so be careful. Like so newbies see this!
Upgrade their stamina and weight a LOT. This flyer is worth it, upgrade his health and melee dmg enough and it can take out raptors on its own (my lvl24 pteranodon killed a lvl20 raptor and succeeded with half of his HP). These lovely birds are easily encumbered by the weight you're carrying so it's preferent if you use lighter armor and leave a few items in the storage so that it's not slow.