Well look around for one and then you find one that you want go to your base and get bout 75 tranq arrows (depends on the level of the big boi)if it's a level 25 then you need 50 tranqs if it's 100+ you need about 150 tranqs just to be on the safe side do not take it to your base if it's aggro on you it is pretty easy to tame just aim the head and run away from it as you tranq it then eventually it'll be down wait for the food to go down and then put in kibble or berries (torpor I good doesn't go down fast ).
I recommend taming this as soon as you get the saddle! They’re a super easy tame, use a crossbow with about 25-80 depending on the level, hop on a pteranodon after shooting it once, land, hop off, shoot it more, rinse and repeat till KO. If you have boosted taming time, just use mejos and it’ll work fine. Up if this helped!
These are the easiest tame ever, just get far away, shoot it with a crossbow repeatedly, when it gets close run and shoot, then boom u knocked out a brontosaurus (I literally have 5 of them that’s how easy they are to tame) please