Among seafood, crabs are of particular value: their harvest exceeds 20% of the total turnover of seafood. However, few people know about the diversity of species, their prey and features. How many species of red crabs exist, 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 - is transformed into powerful claws. During battles with their enemies, crabs can lose one of them, but they quickly regenerate it. In view of this, it is extremely difficult to find living crabs with obvious asymmetry of the limbs.
The carapace, or hard cover, is formed by several layers. The internal ones are made up of chitin - organic matter, and the external ones contain lime. It is in these layers that pigments are contained that give animals a certain shade - for example, red. Crabs of this color are the most interesting representatives of arthropods. This can be seen even in the photo.
How are crabs different from crayfish?
Both types of arthropods 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 carefully look even at the photos of red crabs and crayfish, you can understand how much they differ.
Crayfish have a long and oblong trunk, covered with plates and ending in a tail. Crabs do not have a tail, and the size and shape of their bodies may vary.
The way of movement varies: crayfish mainly move backwards. They can walk forward, but extremely slowly, because massive claws make it difficult to move.
But the crabs run sideways. And very fast.
Types of Red Crabs
In the world there are almost 6, 780 species, each of which differs in size, shell shape, habitat and color. Each in its own way is attractive and curious.
Mangrove Crabs
Exotic inhabitants are the dream of every aquarist. Red mangrove crab is one of such unusual pets that feels great in an artificial reservoir. The largest population in nature lives in southeast Asia. The crab owes its name to its habitat - mangroves. Often he is found on the beaches, where he gets out in search of food.
Description
Mangrove red crab is small in size: the diameter of its carcass does not exceed 5 centimeters. Depending on the genetic predisposition, habitat and living conditions, the color of the carapace may vary, however, individuals of blue-red color are most often found. The legs of the crab are the same red color, but with a dark purple tint. The claws are also red, but you can find animals with greenish, bright yellow or orange paws.
Males and females differ in abdomen: in males, the abdomen is pressed against the back, in females, the distance from the back to the abdomen is greater, and the base of the latter is wider. However, getting into mangrove pets without preparation is undesirable: despite their small size, they can seriously damage their hands with their claws. The maximum life span of a red crab of this breed is four years. And that is pretty much.
Kamchatka crab. Curious instance
Kamchatka red crab is one of the largest crustaceans. Outwardly, it resembles the usual, however, in fact, it is similar to hermit crabs. The body is divided into the cephalothorax, covered with a single shell, and the abdomen - the belly. Abdomain looks similar to a tail that Kamchatka crabs do not have and is bent under the cephalothorax. The carapace performs protective and support functions. There is no internal skeleton, the muscles are attached to the shell. The eyes of the crab are protected by a beak located on the front edge of the carapace.
Unlike males, females have a more developed abdomen. Males have a triangular abdomen. Gills washed by water are closed by the lateral edges of the carapace. There is a stomach in the head of the body, and a heart in the back. The red crab moves with all eight legs, including pairs with claws. The reduced fifth pair hides under the carapace and is used by the creature to clean the gills.
The body of the Kamchatka crab is dark red with a slight purple tint. The lower part of the limbs is a yellowish white hue.
Kamchatka crab - a valuable commercial product
Kamchatka crabs live more than 20 years, but few of them survive to natural death. The constant hunt of man is to blame for everything: king crabs are a valuable commercial seafood, which is in great demand all over the world. When catching animals, males are robbed, the carapace 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, because it is in it that contains nutritious and tender meat. It contains a large number of amino acids, vitamins and minerals that are beneficial to the human body. The insides and chitin shells are processed into fertilizers. Sea animals from Kamchatka have established themselves as delicacies that are considered the main species on the Russian market.
Rainbow crabs
Freshwater red is one of the most popular types of pets for keeping in aquariums. However, preference is given to such animals mainly by foreign lovers of marine life. It is quite difficult to meet such a crab in Russia. Exotic crab can decorate any living corner and bring rainbow colors.
