Intriguing and incredibly unique, Octopuses are cephalopods with three hearts that pump blue blood throughout their eight tentacles. These intelligent sea creatures have multiple brains. Nine, to be ...

An octopus swims at the Ocearium in Le Croisic, western France, on December 6, 2016. (Photo by LOIC VENANCE / AFP) (Photo credit should read LOIC VENANCE/AFP/Getty Images) Octopuses have three hearts.