Why they're awesome: The largest animal on Earth is thought to be the blue whale, but these strange sea creatures can grow even longer — reaching up to 150 feet (46 meters) in length. There are ...

Anyone unfamiliar with the biology of the venomous Portuguese man-of-war would likely mistake it for a jellyfish. Not only is it not a jellyfish, it's not even an "it," but a "they." The ...

Blanket octopus pairs are some of the undersea world’s oddest couples. What’s so startling is the size difference: Males are about the size of a walnut—less than an inch long—but some ...