Crayfish, like lobsters, belong to the crustacean family. They are generally ranked among the oldest living creatures and scientists have conjectured that they have been on the planet for over 200 million years. When living, crayfish have a light brown or dark-green colouring, but once cooked they become, like the lobster, bright red.
The head of a crayfish has a very large jaw and several antennae. The body has five pairs of legs, whereby the foremost two legs are formed into claws, which the crayfish uses to process its food and for its own defence. The chitinous armour that surrounds the body has a reddish to brownish or pale to dark green colouring. Crayfish have very good sensory organs. They have for instance a 360° field of vision and are able to feel even the smallest vibration. Under optimal conditions crayfish can live for up to 20 years. Since there are so many different kinds of crayfish there are no generally accepted statistics regarding size and weight. These range from specimens weighing several kilograms to members of the same family weighing in at only a few grams.
Crayfish typically inhabit clear, calcareous and if possible shallow waters. They feed on plants and smaller animals. A special characteristic of the crayfish is its ability to regenerate lost limbs. This is possible due to the numerous molts. With each molt the lost part grows larger and soon reaches normal size. The crayfish become sexually mature at age three to four years. Females may lay several hundred eggs which they carry around with them until the larvae are large enough to survive alone.