Octopus and squid can hear.

The discovery resolves a century-long debate over whether cephalopods, the group of sea creatures that includes octopus, squid, cuttlefish and nautiluses, can hear sounds underwater.

Compared to fish, octopus and squid do not appear to hear particularly well.

But the fact they can hear raises the possibility that these intelligent animals may use sound to catch prey, communicate with one another or listen out for predators.

The question of whether cephalopods can perceive sound has been controversial since the early 20th Century. Some experiments suggested that blind octopus seemed able to locate the sounds produced by boats or by tapping on the outside of a tank.

But most cephalopods lack a gas-filled chamber, such as the swim bladders that fish can use to hear. That suggested they could not detect the pressure wave component of sound.

However, sensory physiologist Hong Young Yan of the Taiwan National Academy of Science in Taipei, Taiwan suspected that octopus and squid might use another organ called the statocyst to register sound.

http://news.bbc.co.uk/earth/hi/earth_news/newsid_8095000/8095977.stm