Because crayfish and lobsters live their lives moving backward, they have an unusual internal plumbing system. The kidney is located in front of the mouth, so the gill circulation can carry the wastes away from the body. If the kidney outlet was near the back end as in most creatures, the wastes would be carried to the gills. This perfect design enables crayfish and lobsters to live efficiently, whether very slowly crawling forward or rapidly swimming backward.
Crayfish are freshwater crustaceans resembling small lobsters (to which they are related). They are also known as crawfish, crawdads, freshwater lobsters, mountain lobsters, mudbugs, or yabbies. … Crayfish feed on animals and plants, either living or decomposing, and detritus.