First, you have the “egg-laying” sharks. These species, like the horn shark and the swell shark, lay perfecly protective egg cases—you know, those little “mermaid’s purses” you sometimes find washed up on the beach.
The embryo grows safely inside the case, feeding on a yolk sac, until it’s ready to hatch. It’s like a built-in nursery that floats away from mom, no further parenting required.
About 30% of sharks do this, so it’s not the most common strategy. But for the other 70%? Things get a whole lot more hands-on.
