Life Story Of The Crayfish (1963)

crayfish are common animal in many countries of the world they live in or near fresh water you can find them in streams in swamps and lakes some crayfish live in water all of their lives others spend part or all of their lives in Burrows in the banks of streams and other moist places crayfish belong to a class of animals called Crustaceans crustaceans in turn are members of a still larger group of animals called arthropods all arthropods are jointed legged insects such as the Grasshopper And The Bee the millipedes centipedes and the rids such as The Spider and the king crab of the sea are all arthropods the crayfish looks like a small lobster and is about 6 in Long its color usually Blends in with its surroundings like other arthropods the crayfish has a hard outer covering or shell called the exoskeleton this is good protection against many enemies the shell is divided into sections or segments the segments can be seen clearly in the tail each segment of the body has a pair of jointed structures that perform a particular job such as seeing tearing or walking for example the eyes are one pair of structures the eyes are on stalks and can be moved in all directions the crayfish has two pairs of feelers or antenna these are sensory organs like the eyes on the underside of the head are six pairs of mouth Parts which tear the food break it up into tiny pieces for swallowing and put it into the mouth the crayfish has five pairs of legs the first pair are large claws they are used as weapons and for seizing prey the other four pairs are for walking the tail of the crayfish is really its abdomen attached to the underside of the tail are small structures called swimmer RS to which the female attaches her eggs at the end of the tail is the flipper that the crayfish uses for Rapid backward movement this crayfish has lost one claw in a fight with another crayfish crayfish have the power of regenerating lost Parts it will grow another Claw from this stump an aquarium is a good place to learn how crayfish live the aquarium should be arranged as much as possible like the creek where the crayfish lived another good way to observe crayfish is in a shallow tray containing moist sand crayfish can breathe out of water if their gills are kept moist this crayfish moves around cautiously at first as it becomes used to its new surroundings the four pairs of walking legs enable the crayfish to go backward forward and sideways the gills of the crayfish are located under these chest coverings water containing oxygen enters the Gill cavity here and leaves here the crayfish is legs are attached to the gills when the legs move the gills move and stir up the water in the respiratory cavity now let's watch this crayfish's reaction to a strange object the crayfish eyes the pencil approaching it it backs away this crayfish reacts to the pencil by using its claws to defend itself against it crayfish seldom kill other animals and only do so when there is no other food to eat this crayfish seems to be hungry its claws tear the food then its mouth Parts ch chew it up and stuff it in the crayfish is largely a scavenger that is it consumes dead and decaying plant and animal life it in turn is eaten by other animals bull frogs consume a large number of crayfish so do some of the larger animals such as this raccoon and birds such as this Heron it isn't easy to distinguish a male crayfish from a female mating usually takes place in the Autumn later when the warm days of spring appear the female lays her eggs and attaches them to the swimmer rettes on the underside of her tail with a gluey substance the eggs look like berries a female with eggs is said to be in Berry when first laid the eggs are dark as they begin to develop they become lighter in color here movement within the growing embryos can be detected in this closer view the pairs of tiny black spots are the developing eyes as after hatching the young crayfish will stay with the mother for about a month here is a young crayfish shortly it will shed its outer covering in a process called molting and become a little larger this is followed by several more moldings when full grown the crayfish will mol from two to four more times in its 2-year lifespan watch how it emerges from its Old Shell after each molting it will be a little larger than it was before the crayfish has many crustacean relatives one of these is the lobster which may reach a length of 24 in others such as fairy shrimps and cyclops are microscopic in size the colorful and edible rock crab the amusing and common fiddler crab and the hermit crab which takes the shell of another sea animal for its home are also close relatives of the crayfish the class has learned much about the crayfish by observing and recording their findings find out how much you have learned by answering these questions what are the functions of some of the parts of the crayfish how do the legs of the crayfish Aid in breathing how do Crayfish reproduce and develop why can't the crayfish grow without molting for