Most shark eggs will look like a "mermaid's purse." The casings will have long tendrils in order to attach to seaweed or debris, according to the Shark Research Institute .

Most shark eggs will look like a "mermaid's purse." The casings will have long tendrils in order to attach to seaweed or debris, according to the Shark Research Institute .

The white belly of a great white shark serves a surprisingly useful purpose.