You can find them on the terrain types listed for their kind (seems to be working correctly now, so they spawn on their listed terrains). They have a random chance to spawn on any empty terrain square on any planet as soon as you enter the square, so you have to hunt in the open, not on terrain squares with cities built on them. Helps to hunt in a ship with high sensors, or carry macrobinoculars with you so you can unboard and look around. If you see nothing on the square, go to another (or just leave the square and return, but having two adjacent empty squares to move between helps).Edited By: Syn on Year 13 Day 339 15:04
You cannot capture a creature, only kill them, but there is a small (very small) chance for the creature to drop a Mysterious Egg when you kill it, which you can hatch into that type of creature using the incubator found in any ranch, wildlife preserve, or zoo.
Bring a weapon, armor, medical supplies, and macrobinoculars, ideally (although all but the weapon are optional, they just make life easier). You can also bring NPCs or droids along with you to hunt, for more damage output. You may want a high dexterity skill and high weapon skill for better damage output and hit chance, high dodge to avoid getting hit, high strength for more HP, high perception to improve your personal sensor range, and high med skill if you wish to improve the healing done by your medical supplies.
You can hunt creatures that have no creature weapons (see creature rules) and you will take no damage as they will not hit you. Or if you have enough different types of weapons, you can simply find a weapon that will allow you to hit them outside of their weapon range, so you avoid taking damage.
Creatures do move around the squares a bit, so be prepared to chase them down if you don't kill them quickly enough. Their movement seems fairly random. Sometimes they won't move for days, and sometimes they just never seem to stop moving.
If you leave the square, all creatures/NPC bandits will despawn, and new stuff may spawn when you return to it. Good thing to keep in mind if you're about to go somewhere else but have some creatures at low health sitting around; finish them off first.
I guess that about covers it?