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3. Rough Box Crab (Calappa gallus)


The Rough Box Crab (Calappa gallus) is a fascinating species of crab that can be found in the shallow waters of the Indo-Pacific region. With its distinctive box-like appearance, its unusual red coloured carapace and unique behaviour, this crab has become a popular subject for underwater videography, offering a glimpse into its world beneath the waves.

One of the most striking features of the Rough Box Crab is its claws. These claws are large and powerful, and are used by the crab for a variety of purposes, from catching prey to defending itself against predators. However, what makes these claws truly remarkable is the way that they fold perfectly under the crab's carapace, creating a small box-like structure that provides protection and security for the crab.

When threatened, the Rough Box Crab will retreat into its little box, pulling its claws in tight against its body and bury itself completely under the substrate thus sealing itself off from the outside world. This folding ability has earned it the nickname "box crab," and has made it a popular subject for underwater videography. By capturing footage of the Rough Box Crab in its natural habitat, videographers have been able to shed light on this unique adaptation and the way that it helps the crab to survive in a challenging and often hostile environment.

The process by which the Rough Box Crab folds its claws under its carapace is a complex and intricate one. The crab has a specialised joint in its claws that allows it to bend and fold them in a very specific way. When the crab is not using its claws, it will tuck them under its body, where they are held in place by a series of ligaments and muscles.

Underwater videography has allowed researchers and marine biologists to capture this process in detail, providing valuable insights into the anatomy and behaviour of this fascinating species. By studying footage of Rough Box Crabs in their natural habitat, scientists have been able to learn more about the way that these crabs use their claws to catch prey and defend themselves, as well as the way that they fold their claws under their carapace to create their little box.

Despite their small size, Rough Box Crabs are powerful predators of molluscs. Their large, powerful claws are their primary weapons, and they use them to grab and crush their prey.

However, Rough Box Crabs are also preyed upon by a variety of larger animals, including octopuses and some species of fish. When threatened, the crab will retreat into its little box, using its claws and body to seal itself off from the outside world. This behaviour is a crucial adaptation that helps the crab to avoid predation and survive in its challenging environment.

Underwater videography has played a crucial role in our understanding of the Rough Box Crab and its behaviour. By capturing footage of these crabs in their natural habitat, we have been able to gain new insights into the way that they live and interact with their environment. Whether you are a scientist, a videographer, or simply a curious observing scuba diver, the Rough Box Crab is a species that is sure to capture your imagination and spark your interest in the wonders of the underwater world.


To accentuate the red carapace of the crab we added a subtle vignette effect rather than boosting or saturating its colour. Vignette works well when the subject is centred and its surroundings are of no significant story-telling importance.

Filming location:

This short underwater videoclip has been filmed in Bali, Indonesia 🇮🇩

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