The last sighting of the glass octopus was in 2021, and scientists still don't know much about this highly elusive species.

Unlike the octopus's arms, which that animal often uses to move and carry objects, the cuttlefish's eight arms are specialized for grasping prey after the cuttlefish captures it with its two ...

A circulatory system that beats gravity. Spots that dissipate heat. This giant is purpose-built for its size and surroundings. This story appears in the October 2019 issue of National Geographic ...