Crayfish are invertebrates. That means they don't have bones, but they do have an exoskeleton to protect their inner body parts. The crayfish have jointed legs to walk and pick up food. Crayfish have antennae to use senses like feeling, tasting, and smelling. They have a bumpy, not smooth outer layer. Some crayfish are as small as a thumbtack, while others can be as long as cats.
Crayfish are born as eggs, which hold on to their mother's bristles. When the young are born most of them do not survive, however the ones that do survive usually don't live a long life. The eggs are called instars. To tell if a crayfish is a male or a female look at their bristles. If they have a tiny black dot by their bristles than they are a female. If they don't, they are a male.
Crayfish like to stay under rocks or logs. Crayfish are most active at night. Adult crayfish (one year old) are more active at night than young crayfish. Sometimes young crayfish are active during the day. Crayfish movement is usually a slow walk but if scared they move quickly by flipping their tail to swim backward and escape danger. Crayfish predators in the wild include alligators, burbots, chicken turtle and painted turtle, desman, and grackle.
Invertebrates- 1: lacking a spinal column; also of or relating to invertebrate animals 2: lacking in strength or vitality; weak.
Exoskeleton- 1: an internal support covering an animal 2: bony or horny parts of a vertebrate produced from epidermal tissues
Jointed Legs- the point of contact between elements of an animal skeleton with the parts that surround and support it
Antennae- a pair of slender moveable segmented sensory organs the head of insects, myriapod, and crustaceans
Bristles- a short, stiff coarse hair or filament
Instars- a stage in life of an arthropod ( as an insect) between two successive molts
Burbot- a Holarctic freshwater fish of the cod family having barbels on the nose and chin
Desman- a type of otter
Grackle- 1: any of a genus of large American blackbirds having iridescent black plumage 2: any of various asian starlings