Easyest way for me is to take a high lvl karkinos down into the nesting area. Yea it takes a little longer than using a glider and haz suit but if a rockdrake catches you then your haz suit will break pretty fast.
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
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