First, get a bow or a crossbow, then make 11 stone/wood pillars.
Put ten pillars down to make a rectangle with no pillars inside.
Hit it, and it will run after you. Once it's following you, go in the "rectangle" and through the pillars. Once it is in there you want to make sure it doesn't come out. For that put the last pillar down to close up the trap and keep tranquilizing it with your bow/crossbow. This will put it to sleep nice and easy.
Eats Compy Kibble. Usually spawn near the bottom of mountains. When using kibble, no narcotics are required. A level 80 will eat about 21 compy kibble during x1.5 on offical servers. About 7 tranq darts were used to take down the level 80