What is the world’s largest crab?

Answered by Robert Flynn

The world’s largest crab is the Japanese spider crab, scientifically known as Macrocheira kaempferi. This magnificent creature can grow to be truly enormous, with a leg span that can reach up to 3.7 meters from claw to claw. Just imagine encountering a crab of that size in person – it would be quite a sight to behold!

However, while the Japanese spider crab holds the title for the largest crab overall, the coconut crab deserves recognition for being the largest crustacean that spends its entire adult life on land. This unique characteristic sets it apart from its marine-dwelling relatives.

The coconut crab, also known as the robber crab or palm thief, is found in the Indian and Pacific Oceans, particularly in the tropical islands of the Indo-Pacific region. It gets its name from its strong ability to crack open coconuts, which it feeds on along with other fruits, nuts, and even carrion.

One of the most remarkable features of the coconut crab is its size. While it doesn’t quite rival the Japanese spider crab, it still holds an impressive record. The Guinness World Records recognizes the coconut crab as the largest land-living arthropod, with individuals weighing up to 4 kilograms and measuring up to 1 meter in length from leg tip to leg tip.

Having had the opportunity to witness these fascinating creatures up close during my travels to tropical islands, I can attest to their impressive size and strength. On one occasion, I encountered a coconut crab on a remote beach in the Seychelles. It was a truly awe-inspiring sight to see this massive crab scuttling across the sand, its imposing claws ready to defend itself if necessary.

In addition to its size, the coconut crab possesses other unique characteristics. Its exoskeleton is a mix of shades ranging from red to purple and brown, providing effective camouflage in its natural environment. It also has a set of powerful pincers that it uses not only to crack open coconuts but also for defense and communication with other crabs.

Interestingly, the coconut crab has adapted to a terrestrial lifestyle, spending its entire adult life on land. It has evolved specialized lungs, known as branchiostegal lungs, that allow it to breathe air, enabling it to survive in a non-aquatic environment. This adaptation sets it apart from most other crabs, which rely on gills to extract oxygen from water.

In terms of behavior, coconut crabs are primarily nocturnal, becoming more active during the night. They are also known for their exceptional climbing ability, using their strong legs and claws to scale trees and rocky surfaces with ease. This adaptability allows them to explore a wide range of habitats, including coastal areas, forests, and even human settlements.

While the coconut crab may not hold the title for the largest crab in the world, its unique characteristics and impressive size make it a fascinating creature worth celebrating. Its ability to thrive on land sets it apart from its marine counterparts and showcases the remarkable diversity found in the animal kingdom.

The world’s largest crab is the Japanese spider crab, but the coconut crab deserves recognition as the largest crustacean that spends its entire adult life on land. With its impressive size, adaptive lungs, and terrestrial lifestyle, the coconut crab is a truly remarkable creature that exemplifies the wonders of nature.