To tame a Rock Drake you have to steal an egg. Then place it in a very cold place(8 air conditioners should work) and, when it's born, give him Nameless Venom. This can be harvested form the Alpha Nameless(the red ones).
Obtaining this creature will require you to enter the tek trench where puprle liquid and the nests of these creatures lay past the bioluminescent chamber, there you must steal an egg and raise in a cold environment feeding it nameless venom you can get by killing nameless
They lose 1 point of food every 15 seconds, so to time how long until they start starving, multiply their current amount of food by 15 and then divide by 60 twice. This will give you the number of hours left untill the food stat reaches 0.
((15 x food)÷60)÷60