For people withot quetzals to trap them in behemoth walls: If you know where it's hanging from a tree, it won't move from that tree until something comes close enough for it to pounce on. Get prepared with >2 bear traps where you want it to run into. Use only (cross)bow and arrows because torpor goes down fast and tranq darts reload too slowly. Make sure you had a bear trap set up behind it because it will run the other direction if you got the torpor high enough. If torpor isn't high enough it will chase you once the trap breaks. Have a trap set in front of you just in case. Guaranteed it'll have lost a lot of health once it's downed so try to build around it to keep it safe.
Easiest way to tame: make a dino pen, pick one up with an argy, put it in the dino pen then follow along with a basic taming process (knock it out, feed it). Make sure you have lots of narcotics on you!
Best thing about them: they can climb up really steep hills and they can potentially do lots of damage and can be fast.
Where to find: most commonly found on trees (they will be hanging upside down, high up on large trees) in the redwood forest areas (mainly on The Center) or I find lots of them in the Ragnorok desert.
The redwoods are now basically a no fly zone, I lost a quetz, and a pter to these bastards. They jump out of the tree, rip you off your mount, and then pin you and your mastercraft armor to the ground and murder you.