Sometimes, i'll use the playtesting hotkeys to punch up a bunch of animals encounters, then just sit back and watch the show. I call it "The Zoo".
Its quite interesting seeing dozens of different mega-fauna going at it in a giant free-for-all. Of course you have to be careful to not get too close to the action! <g>.
This actually a good way to test the AI, animations, combat system, physics engine, etc all at once.
Visible in this scene: antelope, imperial mammoth, cave lion, short faced bear, irish elk, and aiolornis.