Sharks, Skates & Rays This group of animals (called elasmobranchs) may look similar to their fishy friends, however the significant difference between them is their skeleton is made out of cartilage rather than bone. Sharks, skates and rays lay tough eggs which attach to seaweed. They are often called a Mermaid’s Purse, and can often be found washed up on the beach. Small-spotted Catchshark egg washed up on the beach Sharks Skates & Rays