What do wild crabs eat
What do crayfish look like?
Crabs are unmistakable: with their large claws, long antennae, many legs and shell, they look a bit like animals from prehistoric times. And that's not wrong either:
Their ancestors swam through seas, lakes and rivers nearly 600 million years ago.
The European crayfish belongs to the group of animals called the arthropods, grows up to 18 centimeters long and weighs up to 300 grams.
The females are slightly smaller than the males.
Its body is divided into the head, chest (front body) and abdomen and is covered by a thick armor. This shell is mostly brown in color, but also bluish in some animals.
Crayfish have five pairs of walking legs that sit on the front body.
The first pair of legs has been transformed into large claws with which the crab grabs its prey and drives other species out of its territory.
There are also gills that the crayfish use to breathe on the legs.
There are five other, smaller pairs of legs on the abdomen (only four in the female).
Another pair of legs and the tail together form the tail fan.
Where do crayfish live?
The crayfish is found all over Europe, except in Spain, Portugal, Ireland and northern England.
Crayfish live in clean flowing and standing water.
They especially like creeks, rivers and lakes with a varied subsoil, as they find good hiding places under stones or overhanging banks and tree roots.
What types of crayfish are there?
There are around 35,000 different types of cancer in the world. Close relatives in fresh water are the signal crab and the stone crab.
After the crayfish were almost wiped out by a serious disease - the cancer plague - between 1860 and 1880, the very similar American crayfish, which is immune to the cancer plague, was abandoned here.
Other relatives of the crayfish live in the sea, for example lobsters, lobsters, shrimps and hermit crabs.
How old do crayfish get?
Crayfish males can live to be over 20 years old.
How do crayfish live?
Crayfish are crepuscular and nocturnal. Most of the time they walk slowly over the bottom of the water on their pairs of legs.
In case of danger, they can swim backwards by turning their abdomen into the stomach at lightning speed.
The mating season for the crayfish is usually in October and November. The males behave like real bully: they grab the female with the scissors and throw her on her back.
Then they release the semen and form small packages with the first pair of legs of the abdomen, which they place near the genital opening of the female and on her tail fan.
There are always times in the life of the crayfish when they are particularly endangered: Since their solid shell cannot grow, they have to shed their skin regularly - eight times in the first year of life, five times in the second when they are three years old, and from then on fourth year of life only once a year.
The armor rips open between the chest and abdomen, the crab strips off the old shell and later eats it up.
However, it takes around eight days for the new skin to become firm and into a real shell.
In order not to be easy prey for enemies, the crayfish stay in their hiding place day and night and do not eat.
Crabs shortly after molting are also called "butter crabs" because they are very soft.
Friends and enemies of the crayfish
Eel and catfish in particular eat crayfish. The eels even chase them into their hiding places at night.
How do crayfish multiply?
A few days after mating in autumn, the females lay 50 to 400 eggs.
To do this, they turn on their backs, curve their abdomen forwards and thus form a cavity.
They stick the fertilized eggs to the limbs of the abdomen. They are carried around by the female for about half a year.
The crab larvae only hatch in May and June. Their front body is spherical, the abdomen thin and long, but they already look like small crabs.
They still remain under the protection of their mother: for ten days the crabs cling to their mother with their tiny scissors, only then do they let go and begin an independent life.
Many young crabs are eaten, only ten to twenty percent grow up.
How do crayfish hunt?
Crayfish grab prey with their large claws. With the smaller scissors of the second and third pair of legs, they are divided and brought to the mouth.
What do crayfish eat?
Crayfish eat almost everything that comes before them: aquatic insects, mussels, snails, worms, newts, frogs and fish.
Sometimes they also eat aquatic plants. Since they also eat sick fish and carrion, they are a kind of health police: they keep streams and rivers clean.
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