Crayfish and lobsters live in different environments: Crayfish are small and live in fresh water ponds and streams. Lobsters are larger and live in salt water. However, they have a similar appearance. Both are edible and quite tasty.
We photographed this critter on September 2000 in the parking lot of Herrick Woods, located in Wheaton, Illinois. It was not pleased by our attention and waved its claws at us in a threatening manner.
This is a lobster that was caught on our "lobster cruise" in New Brunswick, September 2006.