You gotta be smart to survive in the wild, and decorator crabs know that so well. These decapods use materials from their environments to decorate themselves to either hide from or repel predators. Some of them look absolutely stunning while others look rather intimidating, especially to predators. We are going to see 8 of them below, let me know which one you think has the best decoration.
1Corallimorph Crab
Scientific Name: Cyclocoeloma Tuberculatum
A corallimorph crab’s carapace grows to about 5 centimeters, having 4 walking legs and a pair of clawed arms at the front. The back side of its carapace is round; however, the rostral area is a bit far ahead. It makes it look like a head with a lateral position of the eyes which is quite fascinating. Another thing is that we don’t know what the actual carapace looks like due to the anemones on top. The colorful beauty of this decorator crab species comes from the coverage of the heavy growth of marine organisms. It is for camouflage against predators during the day, and it gives them a very appealing look also. This crab lives over hard bottom intertidal zones in coral and rocky reefs and shallow lagoons where algae is abundant. And, of course, these nocturnal crabs feed on algae and zooplankton.
2Common Decorator Crab
Scientific Name: Schizophrys Aspera
Despite the decoration, we still can see the orange-red carapace of this common decorator crab. The decorative items that it usually has are the encrusting growths of ascidians, hydroids, and sponges. It also has a carapace size of 5 centimeters, and it has slender claws that are smooth towards the end. The distribution of this decorator crab is in the Indo-Pacific, eastwards all the way to Hawaii. And another useful information about them is that they are poisonous for human consumption.
3Golden Decorator Crab
Scientific Name: Naxia Aurita
A golden decorator crab has a pear-shaped body that is yellow-brown in color along with orange chelipeds with blue trim. It grows to a maximum size of around 7 centimeters, and it camouflages with bryozoans, seaweeds, or sponges. The carapace has small hooked hairs that allow it to attach bits of its decorative items for camouflage. During the camouflage, they remain still and they stay freezing when a potential predator approaches. Males have stronger claws than females, and these claws can inflict a good amount of pain when nipping. These crabs have a distribution across southern temperate oceans including southern Australia where they feed on invertebrates.
4Graceful Decorator Crab
Scientific Name: Oregonia Gracilis
The 5-centimeter carapace of this crab is heart-shaped, and it is brown, gray, or tan in color. It has 4 pairs of long thin walking legs along with a pair of pereiopods with pincers known as chelipeds. The crab uses these chelipeds for defense, feeding, and picking decorative items to decorate its body. Speaking of decorating, the common decorative items that they use are algae, bryozoans, hydroids, and sponges. As for their range, it spreads across the Bering Sea, Japan, and the North Pacific Coast. Their main food source is algae and drifting kelp but they are also scavengers that feed on small marine organisms.
5Moss Crab
Scientific Name: Loxorhynchus Crispatus
Moss crabs are large spider crabs that can grow from 8.8 up to 10 centimeters long. Not different from other decorative crabs out there, this one also has a pear-shaped carapace with short hairs. They use these short hairs to attach various materials for camouflage, and different materials give them different colors. Some moss crabs are brown, dark green, or gray-brown, while others are rather brighter in color. Their favorite decorative items are algae, bryozoans, and sponges, and younger moss crabs decorate more than the older ones. As slow movers, this decoration is very important to them as it protects them from predators out there such as fish and larger crab species.
The range of these decorator crabs is along the southwest coast of North America. They inhabit the middle and deeper reef regions of kelp forests as well as rocky areas or underwater structures. As for the food, they feed on a wide variety of invertebrates, both living and dead, including mollusks, worms, etc. Along with that, they also eat algae and giant kelp as well as small amounts of their decorations sometimes.
6Red Decorator Crab
Scientific Name: Leptopsia Setirostris
With a bright red exoskeleton, decoration is important to avoid being too visible. Their main decorative items are zoanthid polyps, the organisms that are close cousins to both sea anemones and corals. These organisms are flower animals that live socially in dense groupings of identical polyps. The unique thing about a red decorator crab is that it carefully nips individual zoanthid polyps from a larger colony and places them on its carapace. More than that, it also uses its small claws to pick at and remove pieces of detritus between the polyps. No doubt why the camouflage looks absolutely flawless with these decorative crabs.
7Sponge Decorator Crab
Scientific Name: Hyastenus Elatus
Taking camouflage to the next level, this decorator crab covers itself in aposematic sponges to keep predators away. This crab attaches anemones and sponges to the body and grows together with those decorative organisms. The camouflage is so good you cannot even tell the shape of the crab anymore. A sponge decorative crab has a pear-shaped carapace that grows to around 8 centimeters long. It has a distribution around tropical Australia all the way to the West Pacific in Indonesia and Papua New Guinea. These decorative crabs are fond of sponge gardens, especially in coastal bays and estuaries where they can hide.
8Velcro Crab
Scientific Name: Camposcia Retusa
The velcro crab aka spider decorator crab is one of the most beautiful decorator crabs to look at. Its tear-dropped-shaped carapace is around 3 centimeters while the legs can reach 10 centimeters long. The chelipeds of the crab are slender and smooth, making it easy for the decapod to snip and place decoration on its body. A velcro crab has actual living corals and sponges attaching to its carapace to camouflage which is quite fancy.
Their living decoration continues to grow, and there are cases of other animals living in the decoration as well. Spotting one of these can be very difficult because all you see is the algae, sponges, and other sessile organisms. This crab has a distribution throughout the tropical waters of the Indo-West Pacific area, including the Red Sea. They live in coral rubble, seagrass areas, and shallow waters where they feed on meaty food such as small marine organisms.
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