The body is short, broad, and flattened.
Cuttlefish are carnivorous and excellent at capturing prey with their arms.
Although good swimmers, they are not as fast as the related squids , but like the squids cuttlefish have lateral fins used as stabilizers and for steering and propulsion. They swim by jet propulsion, forcibly expelling water through a siphon. Except for the squid genus Loligo, cuttlefish have the best cephalopod eyes, which are highly complex. When disturbed, cuttlefish eject a cloud of dark brown ink from an ink sac for protection. The ink gland and ink sac are specializations of the rectal gland.