Giant crabs come out under cover of darkness in Belize

Channel clinging crabs are enormous and beautiful creatures that emerge under cover of darkness to hunt in the night. They inhabit reefs throughout Florida and the Caribbean and they are the largest of the crab species in these parts of the ocean. Their shell, or carapace measures at least 15cm (6 inches) across and their legs reach another 60cm (2 feet).

Too large to hide in the usual crevices, they spend the day hiding under ledges and in small caves, relying on their camouflage to help disguise them as rocks and chunks or coral. They come out at night to feed on algae and decaying plants and animal matter. Janitors of the reef, they clean up organic material that would rot and cause bacterial growth. This keeps the water clean and also helps reduce the impact of rotting matter on the corals and sponges. They play a role in keeping algae growth in check as well, which benefits the reef. These crabs are an important food source for larger predators such as octopus and even some stingrays.

Scuba divers on this reef in Belize waited until nightfall to slip beneath the waves. They navigated by lights and explored what is a different world after the sun sets. These gigantic crabs are numerous as they comb the reef and sandbars in search of their food. They are fascinating to watch as they use their giant claws to pick up food and pass it into their mouths. Resembling mechanized robots, their movements are mesmerizing.

Not much is known about these crabs. Researchers know that they are omnivores and that they are nocturnal, but there is still a lot to be learned about how they breed, how long they live, and their whole role in the complex web of life that exists in our oceans.