Shark eggs are honestly fascinating things. We call them Mermaid’s or Devil’s Purses because the eggs are encased in a hard shell to protect them while the baby shark inside grows into its own mini-adult version.

I talk a bit about Mermaid’s Purses here in this ask, but I’ll talk more about them here. More under the cut :)

The eggs sometimes attach themselves to rocky outcrops, seaweed or wherever really so the egg doesn’t float away in the ocean current. The cases are made of collagen and feel a lot like leather. There’s sometimes fibrous material on the outside of the egg that likely helps them attach to stuff. There’s a variation in the style and appearance of the egg cases, for example they can be smooth and glossy or striated or bumpy.

Because sharks either carry their eggs inside and thus give birth to live pups, or lay them, oviparity in the sharks is a thing (retaining the eggs for longer until the pups are ‘hatched’ is viviparity btw). Anyway, the eggs are kept in the oviduct for a while before they’re dropped as unhatched eggs with oviparity.

Bullhead Sharks have very distinctive egg sharks like an auger (corkscrew, think corkscrew) which allows the egg to wedge in crevices on the seafloor to protect them from predators.

Crested Bullhead Shark egg

[image source: Wikipedia]

Bamboo Sharks and Zebra Sharks both lay their eggs on the bottom of the ocean with them being oval and covered in sticky fibres to stick better.

Brown-banded Bamboo Shark egg

[image source: Wikipedia]

Catsharks too lay eggs. The Catshark egg is purse-shaped with tendrils to help anchor them on the sea floor (honestly, these are some of the most Iconic Looking Mermaid Purses).

Catshark egg

[image source: Wikipedia]