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 ...

With documented swimming speeds of up to 46 miles per hour, mako sharks represent the world’s fastest elasmobranch species.

The dozen or so species that make up Grimpoteuthis are called Dumbo octopuses because of the two large fins—one on either side of the mantle—that protrude like ears. Add in the octopus’s ...