Broad-toed crayfish (or crayfish) a species of decapod crustaceans from the infraorder Astacidea. Lives in fresh waters throughout Europe.
Description
Refers to arthropods, detachment decapods. Well known to a person not only in appearance, but also in taste. Lives exclusively in fresh water. Has wide massive claws. Depending on gender, they vary in color and size. Males are much larger than females, have large claws in size and strength. The female is distinguished by the presence of two pairs of ventral legs, which remain underdeveloped. Its abdomen is much wider than that of the male. The body of the cancer is large, covered with a shell. He has 10 legs. Considered the largest representative of freshwater arthropods. Females grow up to 10-12 cm, males from 14 to 17 cm. Sometimes you can meet a representative of the species with a length of 20 to 27 cm, weighing 100-200 g. As a rule, such cancer has lived a long life and is in old age.
Females have an additional pair of biramous legs that are designed to hold eggs.
Origin
Appeared more than 100 million. years ago, presumably during the Jurassic period. His moving eyes saw even the most ancient dinosaurs. The appearance of cancer hasn’t changed much since then.
How to distinguish broad-toed cancer from narrow-toed
You will never meet broad-toed crayfish in polluted rivers, ponds and other bodies of water they run away from there or die. This is the main difference from relatives. In many ways, the narrow-toed and broad-toed are similar, but outwardly they are distinguished by the width of the claws in the first case they are narrow, in the second they are wide.
Broad-toed crayfish is a delicacy, popular with gourmets, especially for its wide claws, which contain a lot of meat. They are clean by their presence or absence they judge the quality of the water in the reservoir.
What does it look like
It is dark olive, greenish-brown, brown. Crayfish are excellent masters of disguise, they have the ability to merge with the bottom and imitate its color. The body consists of the cephalothorax and abdomen.
The shell serves as protection for internal organs from damage. With the help of long whiskers-antennas, the olfactory and tactile function is manifested. At the base of the head is a protrusion called the rostrum. Black eyes resemble beads, they are located on both sides of the head. This position of the eyes gives him a wide view. The organs of vision of the animal are of the facet type, it consists of 2-3 thousand small eyes. The structure of the mouth includes:
- One pair of mandibles (upper jaws).
- Two pairs of Mastillas.
- Three pairs of maxillepeds (mandibles).
The tail of the crayfish is quite long and elastic, with its help the crayfish can swim, move backwards.
Where does it live
Distributed throughout Europe except Greece, Spain, Portugal, Italy. The broad-toed crayfish lives in the Baltic Sea, in the water bodies of Lithuania, Estonia and Latvia. in Eurasia, the largest number of crayfish of this species is found in the northwestern part.
Lives mostly in fresh waters. Can exist only in clear waters, in a flowing reservoir. As permanent housing choose a depth of 1 to 4 m.
What does it eat
It is omnivorous, consumes plant and animal food. Among plants, he prefers water buckwheat, water lily stalks, choral algae, which contain a lot of calcium. Worms, larvae, snails, water fleas, tadpoles, amphipods are a favorite delicacy of crustaceans.
The diet includes carrion, arthropods eat decaying animals and fish.
Lifestyle
During the day, the crayfish hides in its hole, at night it hunts. While in shelter, he grabs his victim with powerful ticks.
In his free time from hunting, the cancer is in its own hole, it closely monitors its safety. Burrows can be very long, up to 1 m in length.
reproduction
Sexual maturity in broad-toed crayfish occurs quite late in males by the 3rd year of life, in females by the 4th. The species has the following breeding features:
The life expectancy of broad-toed crustaceans is 10-12 years, but under very favorable conditions they live up to 25 years.
This type of crayfish is distinguished by the special behavior of males during the mating season. They are very cruel and aggressive, even towards their females, because of which the latter often die.
How Coition Happens:
Such actions are unpleasant and painful for the partner, therefore, during the spawning period, females often hide in shelters.
natural enemies
The most malicious enemy of the broad-toed crayfish is the eel, which can penetrate its hole. Burbot, pike, perch eat arthropods. Larvae feed on bream and roach.
population
There are a number of factors that contribute to the reduction of the number of individuals:
- The height of the epidemic of crayfish plague.
- Illegal fishing of arthropods.
- Violation of the ecological situation of water bodies.
Interesting Facts:
- prone to cannibalism. In conditions of lack of food, they can eat their own kind, weak and sick individuals.
- In Sweden, in ancient times, aristocrats ate crayfish meat and considered it a delicacy.
- Cancer is considered not a kosher animal, so the Jewish people do not use it for food.
- Often, males exhausted by mating games eat their partner, since during mating games they do not eat.
- One cancer eye contains approximately 300 micro-eyes, because the visual organs differ in the facet type.
