The Spider Decorator Crab, also known as the Velcro Crab or Harlequin Crab, is a unique type of marine crustacea that belongs to the Inachidae family.
Spider Decorator Crab is famous for its special habit. It attaches living sponges and corals to itself. This behavior helps the crab to camouflage, or hide, from its enemies.
Where Can We Find the Spider Decorator Crab?
Spider Decorator Crabs live in the tropical waters of the Indo-West Pacific area. This includes the Red Sea.
In these places, you could find a Spider Decorator Crab hiding under a moving piece of seaweed or sponge. This crab is often decorated with colorful or dull objects, so it can be hard to spot!
What Does the Spider Decorator Crab Look Like?
Looking at a Spider Decorator Crab, you might only see its eyes and pincers. That’s because it’s usually covered in decorations!
But if you could see underneath all that, you’d find a pretty small crab.
Spider Decorator Crab has a body that’s only about 3 cm wide. It has long eyestalks that can’t be pulled back into its body.
It also has a pair of pincer-like claws, and eight other legs that are longer than the claws.
Why Is It Called the Velcro Crab?
The body of the Spider Decorator Crab is covered in fine, stiff hair that are hooked at the ends.
These hair look and act just like the rough side of a piece of Velcro. They help the decorations stick tightly to the crab’s body. This is probably why people started calling it the Velcro crab.
Why Does the Spider Decorator Crab Decorate Itself?
The Spider Decorator Crab is part of a group of crabs known as decorator crabs. These crabs have a built-in habit of decorating themselves.
Spider Decorator Crabs use all kinds of materials, like pieces of shells or even living organisms like corals and sponges. The decorations help it hide from its enemies.
The decorations also protect the Spider Decorator Crabs from harm if they taste bad or hurt the enemy.
How Does the Spider Decorator Crab Decorate Itself?
At first, people thought Spider Decorator Crabs used a kind of glue to stick decorations to their bodies. But studies found that the materials actually stick to the hooked hair on the crabs’ bodies.
The Spider Decorator Crabs use their claws to pick up pieces of decorating material. They cut or tear the materials into the right size and shape.
Then they use their mouthparts to soften the edges of the material. After that, they rub the material against their bodies to make it stick to the hair.
What Challenges Does the Spider Decorator Crab Face?
Decorating can be hard work for a Spider Decorator Crab. It takes energy to find and attach the decorations.
The crab also has to use more energy to carry the extra weight of the decorations. This might be why bigger Spider Decorator Crabs don’t decorate themselves as much as smaller ones.
Smaller Spider Decorator Crabs need camouflage to help them stay safe from enemies.
Where Does the Spider Decorator Crab Live?
The Spider Decorator Crab lives in the Indo-west Pacific region. It lives in places like East Africa, the Philippines, and the French Polynesian islands.
In Singapore, you can find Spider Decorator Crabs on offshore islands and coastal areas.
This crab likes to live on rocky shores, coral reefs, and seagrass beds. It can also live in deeper waters of up to 200 m.
What Does the Spider Decorator Crab Eat?
The Spider Decorator Crab is a scavenger. This means it eats dead organisms and decaying matter.
How Does the Spider Decorator Crab Reproduce?
There isn’t a lot of research done on how Spider Decorator Crabs reproduce. But studies of other crabs in the same family suggest that male crabs have to first court, or attract female crabs.
After mating, the female crab carries the eggs in her abdomen until they hatch into free-swimming young crabs called zoea.
What Threats Does the Spider Decorator Crab Face?
The Spider Decorator Crab doesn’t have an official conservation status. This means we don’t know for sure how many of them are left in the wild.
But in Singapore, the Spider Decorator Crab is listed as ‘Vulnerable’. This means there might be only 250 to 1000 mature Spider Decorator Crabs left in Singapore.
The main threats to the Spider Decorator Crab are the aquarium trade and habitat loss. So, it’s important to protect the crab’s habitats and not to buy crabs that are caught in the wild.
Spider Decorator Crab Characteristics
| Reef Safe? | With caution |
| Care Level: | Somewhat Easy |
Scientific Classification
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Family: | Inachidae |
| Genus: | Camposcia |
| Scientific Name: | Camposcia retusa |
| Also Known As: | Spider Decorator Crab, Velcro Crab, Harlequin Crab |
| Conservation Status: | Unknown |