So, how do decorator crabs achieve this remarkable feat? Most decorator crabs employ various marine organisms as their “building material.” For every decorator crab species, there are almost as many other species that serve as decorations. These can include corals, seaweeds, sponges, sea fans, anemones, seagrasses, sea urchins, bryozoans, hydras, and even other small crustaceans.
The secret to their attachment lies in specialized hooked bristles called “setae” that are scattered across their bodies. These setae function similarly to Velcro, allowing decorator crabs to select and attach their chosen adornments securely. While the process may sound straightforward, these crabs can be incredibly selective about their attire, making the task more complex than it seems.
Decorator crabs are known to choose their decorations carefully, as demonstrated by a study conducted in 1940 by British zoologist and camouflage expert Hugh Bamford Cott. He relocated decorator crabs to various locations and observed that each crab immediately began redecorating itself using local materials upon arrival. This adaptability showcases the incredible versatility of decorator crabs in incorporating different elements into their disguises.
Interestingly, decorator crabs don’t use their elaborate disguises to showcase or attract mates but primarily for concealment and protection from predators. Their preferred decorations include seaweeds, colonies of bryozoans, and hydras, among others. As long as they stay close to their mimicked environment, the local camouflage is highly effective.
Some decorator crabs go beyond camouflage and use their decorations as a means of defense. An example is the boxer crab (Lybia tessellata), also known as the pom-pom crab, which attaches anemones and urchins to its claws, using them as weapons when provoked. The crab threatens potential predators by waving its anemones, whose tentacles are equipped with stinging cells. This mutually beneficial relationship between the crab and the sea anemone involves a level of cooperation that benefits both species.
Decorator crabs also occasionally employ toxic decorations, deterring predators with a bad taste or a painful sting. While these crabs may not look formidable at first glance, their creative use of decorations makes them a unique and fascinating part of the marine ecosystem.
In conclusion, decorator crabs are true masters of disguise in the ocean, using an array of materials to blend into their surroundings and evade predators. Their ability to attach various elements to their bodies showcases their adaptability and resourcefulness in the face of danger. While their disguises may not be for show, they certainly add a touch of intrigue to the captivating world of marine life.
