Easy to tame all you gotta do is place loads of standing torches around the nest kill their parents or lead them away then wait for them to hatch and bang me and my friend got twin 150s when he placed torches and I killed all the Rex that came near
These guys are op I mean I just killed 10 carnos with a trike if your trike is higher or equal in level to a carno or therizino it can easily fight them because of it's knock back attack just pump health, meele damage and stamina. They are great for collecting thatch and berries.
I dare you to raise one!! They are savage if you got two high lvl parents (about lvl 140ish) and you get imprinting on it. The thing will become an adult with about 230% melee and basically one chomp any bronto!!! But on the down side you loose your job and your girlfriend
Another way to do the math for food stat loss when raising rockdrakes. They lose 1food per 15 seconds. you lose 4 food every minute. (My advice go up to 5 if your paranoid like me and get Arked. 60mins x 4food = 240, (240 is the total food stat loss per hour.)
Now take your total food stat and ÷ by 240, and you will have a correct time as well.