A cuttlefish swims in an aquarium at the Scientific Center of Kuwait in 2016. Cuttlefish showed impressive self-control in an adaptation of the classic “marshmallow test.”

A cuttlefish swims in an aquarium at the Scientific Center of Kuwait on March 20, 2016, in Kuwait City. / AFP / YASSER AL-ZAYYAT (Photo credit should read YASSER AL-ZAYYAT/AFP via Getty Images)