Bird poop may be the key to stopping the next flu pandemic. Here’s why.

First come the horseshoe crabs. Hoisting their round, tank-like shells, they trundle out of the Delaware Bay under the first full moon in May to mate and lay their eggs.

​ First come the horseshoe crabs. Hoisting their round, tank-like shells, they trundle out of the Delaware Bay under the first full moon in May to mate and lay their eggs. Read More Breaking News, Latest News and Videos | CNN