Some quests will require that you capture, instead of slay, a monster. Guess they're into live specimens! Capturing can be a bit more complicated, but as you get the hang of it, it will become a nice convenience to have.
Here's how you pull off a successful capture.
First, bring along a Shock Trap and/or a Pitfall Trap , along with Tranq Bombs or Tranq S ammo. When you engage the monster, fight like usual, but pay attention for signs of exhaustion. Once you see visible signs of a monster's exhaustion, such as limping , the monster is weak enough to be trapped. Follow the monster wherever it goes and lay down your trap. It takes a bit of time so make sure you have a big opening so you don't get hit and interrupted.
Note!: If you have the armor skill Capture Guru , then if you have marked the monster with a Paintball , the monster's icon will flash the moment the monster is capturable. A monster typically becomes capturable before it will begin to limp, so it can save you time. Also, if it is a smaller monster you are trying to capture, it can prevent you from going too far and slaying it instead.
Lure the monster into the trap by standing near it. When the monster is confined within the trap, toss your Tranq Bombs. If you are not moving, you will simply drop the Tranq Bomb in front of you. To throw the Tranq Bomb, move forward with the left c-stick while pressing Y . Two Tranq Bombs seals the deal, and it's a quest clear! You can't use Tranq Bombs on a monster not trapped, it won't work.
Capture is incredibly useful because it can be done in any slaying quest to clear the quest . If the quest requires that you slay a monster, but the hunt isn't going very well, you can capture the target monster to save a few minutes of pain, and the quest is still quest clear. Capturing will also net you more rewards, and sometimes has a higher chance of getting you the really rare stuff. If the quest requires that you capture, however, killing the monster is an automatic quest failure !