Stingrays are oviparous, laying eggs inside a protective hard case that's commonly referred to as a "mermaid's purse". The embryos develop inside their cases for 3-5 months before hatching. They are cartilaginous fish, closely related to sharks and rays.

And now, here are some dancing baby skates to brighten your day. This video was shot at the Hatfield Marine Science Centre in Newport Oregon.