Lyre Crab: Mortal Enemy of the Lobster

Those big ugly Lyre Crabs spell trouble for commercial lobster fishermen. The trouble is, crabs and lobsters are sort of like rival gangs. They tend to stick to their own. This turf war has been going on for thousands of years in the Pacific Ocean. This means that when one Lyre Crab decides to wander into a lobster trap, the passing by lobsters are detoured from entering. Eventually what you have is a trap full of worthless crabs (as far as a lobster fisherman is concerned).