Crayfish are crustaceans that are also known as crawdads, crawfish, and freshwater lobsters; they are closely related to lobsters, crabs, and shrimp. There are about 150 crayfish species in North America, and over 540 species worldwide.
Crayfish live in streams, rivers, swamps, ponds, and other freshwater habitats. Most crayfish are strictly aquatic but some live in semi-aquatic environments. The semi-aquatic crayfish burrow into the soil to get to water (so that they can breathe). Some can also be put in private aquarium to be used as pets