What's that scent wafting through the murky waters off the coast of Georgia? Well if you're a mud crab, you'll know that it's the smell of fear. But where does it come from? And how do we know? Join Guy Raz & Mindy Thomas for Who, What, When, Where, Why, How, and Wow in the World of secret signals of the animal world. (And stick around as they potty-train a Blue crab. Trust us on this one.) Originally Aired April 30th 2018.