Any collision with a tree creates a noise which can be heard by all crabs within a crab's hearing radius. On hearing a tree collision a crab will turn in the direction of the tree. Crab avoids collision going off in a reflective direction. Crab avoids collision going off in a reflective direction. Crab avoids collision going off in a reflective direction.
Crabs are afraid of wolves.
When a crab comes within 20 meters of a wolf it turns and moves away. The above work is covered by the GNU Free Documentation License and GNU Public License unless explicitly stated otherwise by the author.