Mermaid's Purse

Most sharks and skates lay strangely shaped eggs sometimes called a ‘mermaid’s purse.’ These consist of an egg case in a thin capsule made of collagen. They often are square or rectangular with stringy or pointy corner horns, but can come in a variety of odd shapes. A few sharks, such as the Port Jackson shark, have helical egg cases which are secured into the sand like drill bits. Shark eggs can wash up on the beach and are often hand-sized, although the largest recorded was over 2m long. Female sharks lay fertilized eggs onto the sea floor where they stay until they hatch, not needing any more attention from their mother. Some shark eggs contain several baby sharks which cannibalize each other before hatching to ensure that only the strongest baby survives.