Among seafood, crabs are of particular value: their production exceeds 20% of the total turnover of seafood. However, few people know about the diversity of species, their prey and features. How many types of red crabs are there, and how do they differ from each other?
General characteristics
Crabs, or short-tailed crayfish, are representatives of the type of arthropods, the class of crustaceans and the order of decapods.
One of the five pairs of limbs - the front - has been transformed into powerful claws. During fights with their enemies, crabs can lose one of them, but quickly regenerate it. In view of this, it is extremely difficult to find live crabs with a clear asymmetry of the limbs.
The shell, or hard cover, is formed by several layers. The inner ones are made of chitin - organic matter, and the outer ones contain lime. It is these layers that contain pigments that give animals a certain shade - for example, red. Crabs of this color are the most interesting outwardly representatives of arthropods. This can be seen even in the photo.
How are crabs different from crayfish?
Both speciesarthropods are similar to each other and belong to the same class of crustaceans. However, the presence of frightening claws, four pairs of walking legs and a chitinous cover does not make them the same. If you look closely even at the photos of red crabs and crayfish, you can understand how different they are.
Crayfish have a long and oblong body, covered with plates and ending in a tail. Crabs do not have a tail, and the size and shape of their body may vary.
The way of movement also differs: crayfish mostly move backwards. They can also walk forward, but very slowly, as massive claws make it difficult to move.
But crabs run sideways. And very quickly.
Types of red crabs
There are almost 6,780 species in the world, each of which differs in size, shell shape, habitat and coloration. Everyone is attractive and curious in their own way.
Mangrove crabs
Exotic inhabitants are the dream of every aquarist. The red mangrove crab is one of those unusual pets that thrives in an artificial pond. The largest population in nature lives in southeast Asia. The crab owes its name to its habitat - mangroves. It is often found on beaches where it goes in search of food.
Description
Mangrove red crab is small in size: the diameter of its carcass does not exceed 5 centimeters. Depending on genetic predisposition, habitat and living conditionsthe color of the carapace can vary, however, blue-red specimens are most common. The legs of the crab are the same red, but with a dark purple tint. The claws are also red, however, animals with greenish, bright yellow or orange paws can be found.
Males and females differ from each other in the abdomen: in males, the abdomen is pressed against the back, in women, the distance from the back to the abdomen is greater, and the base of the latter is wider. However, climbing to mangrove pets without preparation is undesirable: despite their small size, they can seriously injure their hands with their claws. The maximum lifespan of a red crab of this breed is four years. And that's quite a lot.
King crab. Curious specimen
King red crab is one of the largest crustaceans. Outwardly, it resembles an ordinary one, however, in fact, it is similar to hermit crabs. The body is subdivided into the cephalothorax, covered with a single shell, and the abdomen - the belly. The abdomen is outwardly similar to the tail, which is not found in king crabs, and is bent under the cephalothorax. The shell performs protective and supporting functions. There is no internal skeleton, the muscles are attached to the shell. The eyes of a crab are protected by a beak located at the front edge of the shell.
Unlike males, females have a more developed abdomen. Males have a triangular abdomen. The water-washed gills are closed by the lateral edges of the shell. At the head of the body is the stomach, the heart is at the back. The red crab moves with all eight legs, including a pairwith claws. The reduced fifth pair hides under the shell and is used by the creature to clear the gills.
The body of the king crab is dark red, with a slight purple tint. The lower part of the limbs is yellowish-white.
King crab is a valuable commercial product
King crabs live for more than 20 years, but few of them live to a natural death. Constant human hunting is to blame for everything: king crabs are a valuable commercial seafood that is in great demand all over the world. When catching animals, males are robbed, the length of the shell of which exceeds 13 centimeters. Females try not to catch. Crab claws are considered a special delicacy.
The right claw is the most valuable and has an exquisite taste, since it is in it that the nutritious and tender meat is located. It contains a large amount of amino acids, vitamins and minerals that are beneficial to the human body. The entrails and chitin shells are processed into fertilizer. Marine animals from Kamchatka have established themselves as delicacies, considered the main species in the Russian market.
Rainbow crabs
Red freshwater is one of the most popular types of pets for keeping in aquariums. However, preference for such animals is given mainly by foreign lovers of marine life. It is quite difficult to meet such a crab in Russia. An exotic crab can brighten up any living space and bring rainbow colors.
Appearance
Rainbow red crab by structuremost of all resembles an ordinary representative of the order of decapod crustaceans. It stands out primarily for its color: bright, attractive and unusual. The crab shell is dark blue, legs are orange or red, large claws are gray or bluish. The abdomen, unlike the back, is pale white with bluish-blue streaks. The diameter of the red crab shell is usually up to 20 centimeters.
The rainbow species got many names precisely because of its color. According to the scientific classification, in Latin it is called Cardisoma armatum, English speakers call it patriot, indigo, tricolor. Due to its terrestrial lifestyle, this rainbow red crab is often referred to as a terrestrial crab.
