Crabs

Crabs are crustaceans that can survive in both marine and terrestrial habitats. They are members of the suborder Brachyura. These creatures, which have a strong exoskeleton formed of mineralized chitin, are particularly skilled at surviving severe settings. They are very swift and agile, and because of their modified legs, they can walk sideways with ease. Crabs must continue to molt repeatedly after being juveniles in order to reach adulthood. They have a thick shell covering them since doing without would stop them from growing. Hormones work together to regulate the molt cycle. The old shell softens and partially erodes in preparation for molting, while the foundational layers of a new shell develop underneath.

But the crab's strong pair of pincers is what makes it unique as a predator of sea urchins. These crab legs, also known as chelas, are thought to have a specific purpose. These work well for both feeding and defense for them.

Fresh crabs are well-suited to overcome the sea urchin's defenses because of their hard shells and strong pincers. The crab's claws allow it to quickly crush the sea urchin's outer body after it has gained a grip.