Representatives of the class of crustaceans inhabit reservoirs exclusively with clean and fresh water. That is why crayfish have become tacit "biological indicators": by their presence or absence in a particular body of water, one can determine the degree of environmental pollution.
Where do crayfish live?
Cancers are underwater inhabitants that need special living conditions. The fact is that they inhabit only fresh water bodies (salty sea water does not suit them). In addition, these creatures do not tolerate increased acidity and are painfully susceptible to environmental pollution.
Crayfish live mainly in reservoirs with a hard bottom. They will not inhabit reservoirs with a sandy or too muddy bottom. The most optimal habitat for most crayfish is a reservoir with a rocky bottom. In it, crayfish hide under driftwood, under stones, in coastal slopes and wash-outs. But these are all temporary shelters. Their permanent lair is burrows dug under water near the coast.
Where and how do crayfish winter?
Crayfish spend winters in places of their permanent registration, i.e. where they live. In late autumn, these underwater inhabitants try to descend as deep as possible, since at depth the water is warmer in winter than at the surface. Keeping warm in winter is one of the main tasks of all crustaceans. The fact is that crayfish, unlike amphibian frogs, do not fall into anabiosis (temporary numbness of the body), which allows amphibians to endure cold weather by slowing down all processes in the body.
Male crayfish spend the lion's share of the time (up to 20 hours a day) in their burrows half asleep. Their burrows are somewhat reminiscent of people's dwellings: the burrow has a corridor, the length of which can reach 3 meters, and several branches. One of these branches is a kind of "rest room" of crayfish. In the rest of the "rooms" they keep stocks of this or that food.
During the waking hours, crayfish come out of their burrows in search of food. They wander along the bottom and nibble algae or catch small animals. In general, crustaceans are omnivores. They can eat both plant and animal food: rotten meat, worms, beetles. These creatures can be safely called the orderlies of reservoirs, since they rid the environment of rot and decayed corpses of small animals by eating them.
Passive winter life is typical only for male crayfish. Their females, on the contrary, need to take care of their offspring during this period. The fact is that in October, after the characteristic autumn mating, up to 200 fertilized eggs are attached to the abdomen of the females. From this time on, female crayfish should pay close attention to these eggs: make sure that they are regularly washed with water, do not silt up and do not become polluted.
The eggs will be hatched by females for exactly 8 months. All this time, future offspring need responsible care and increased attention. That is why females are forced to regularly walk along the bottom in winter. Otherwise, future crustaceans will simply die. If the care for the offspring is done conscientiously, then in May scanty crustaceans are born.
