Decorator Crab: The 'chameleon' species on the seabed

Decorator crab is the name for many crabs of different species, belonging to the superfamily Majoidea, which prefer to use materials from their surroundings to camouflage, or repel, predators.

From spider crabs, sea crabs, moss crabs, to toothed crabs and arrow crabs, there are over 700 different species of crabs in the superfamily Majoidea - ornamental crabs. These crabs often create a camouflage to cover their bodies with a variety of "ornaments" that sometimes go beyond our imagination.

Ornamental crabs are crabs of several different species, belonging to the superfamily Majoidea, that use materials from their environment to hide or repel predators. They decorate themselves by gluing mostly sedentary animals and plants to their bodies for camouflage, poisonous creatures to ward off predators.

According to Marine Madness, most of these crabs use other marine life as "building materials," which include corals, seaweeds, sponges, sea fans, anemones, seagrasses, sea urchins, and sea urchins. bryozoans & hydrozoans (locally specific organisms often confused with algae or corals) and even other small crustaceans.

In 1889, William Bateson observed in detail how these crabs fixed the material on their backs. He notes that if you deliberately remove their camouflage cover, immediately after being released, they will remake a camouflage cover identical to the previous one.

However, using other creatures as camouflage does not mean killing them. On the contrary, they are linked together in a symbiotic, mutually beneficial relationship.

In nature, animals are under pressure to change to blend in with their habitats or to hide their form; hunted animals thereby evading predators and predators can attack undetected.

The degree to which ornamental crabs are special to their ornaments was clearly demonstrated by research conducted in 1940 by British zoologist and camouflage expert, Hugh Bamford Cott, who studied the great spider crab (Hyas araneus) in the Atlantic Ocean.

Reviewing studies done by different authors, Hultgren and Stachowicz show that some species are very specialized in their selection of camouflage. For example, Pelia tumida is decorated only with sponges; Macropodia rostrata and Libinia dubia selected the toxic algae Dictyotahesiais in some places, while Inachus phalangium selected similar algae for the most exposed body parts; and Stenocionops furcata choose three colors Calliactis anemone for its shell.

Cott has moved some of these decorative crabs from their home off the coast of England to different locations, and has found that every time they are repositioned, they immediately begin decorating. rebuild its camouflage with local materials - in fact, each crab adapts its camouflage to its environment.

It is found throughout the world's oceans and seas. It can be seen at night because of the reflection of its eyes in the sea. The camouflage of this animal is so good that it is difficult to recognize them during the day.

In addition to camouflage to protect themselves, some crab species have gone even further with the use of ornaments - using them to strengthen their defenses in other ways. One example is the use of sea anemones, sea urchins and hydrozoans, all of which can cause a nasty sting to any potential predator if they get too close. On the other hand, applying poisonous seaweeds can leave an unpleasant (and potentially fatal) taste in the mouth for anyone who dares to risk attacking them.

In fact, the lifespan of these crabs has not been estimated so far.

Moreover, some species also know how to use their camouflage to attack. A good example is the boxer crab (Lybia tessellata), also known as the pom-pom crab, which attaches sea anemones and sea urchins to its claws and uses them as weapons.

There are about 700 species of ornamental crabs. Some species of crab include Acanthonyx dentatus, Macropodia rostrata, Oregonia gracilis, Libinia emarginata, Achaeus spinosus and Camposcia retusa.

If provoked or attacked by a predator, they intimidate the predator and try to stop it by waving sea anemones around, their tentacles fully equipped with cnidocytes (burning cells). .

The total population size of these crabs is unknown.

Other ornamental crabs even take advantage of the aquatic species Hydrichthella epigorgia, which, like corals, is made up of countless small polyps that work together as a collective organism. However, unlike most hydrozoan species, the polyps of this species do not have feeding tentacles, but instead are sticky polyps that capture microscopic food and slowly transfer them into the "mouth". Some particularly cunning species have taken advantage of this feature and attached them to their claws to create a sticky and effective pair of fishing rods.