First record of tool use in an invertebrate – An Octopus – Video & images

15/12/2009 23:13:13 Tool use in an invertebrate: the coconut-carrying octopus
December 2009. Until now, tool use has been considered the preserve of the "higher" mammals and a few birds. However Museum Victoria scientist's Drs Julian Finn and Mark Norman have recorded the first case of tool use in an invertebrate animal. The researchers have discovered dramatic behaviour by a tropical octopus that selects, stacks, transports and assembles coconut shells as portable armour.

Fetch and carry
Many octopuses use available objects (such as shells, rocks or discarded cans) for shelter, but these behaviours are not considered as tool use. However the Veined Octopus, Amphioctopus marginatus, goes a step further and prepares, arranges and carries pairs of coconut shells up to 20 metres to reassemble as shelter when required. 

The researchers have discovered dramatic behaviour by a tropical octopus that selects, stacks, transports and assembles coconut shells as portable armour. Credit Roger Steene.

‘Stilt walking' octopuses
Julian and Mark spent more than 500 hours diving in remote Indonesian waters to observe and film these animals. They watched octopuses dig out coconut shells from the ocean floor; empty the shells of mud using jets of water, stack two empty shells hollow-side up, and carry the shells underneath their body in a unique lumbering gait they call ‘stilt-walking'. This series of actions are among the most complex ever recorded for octopuses.

Lightweight armour
The Veined Octopus probably evolved this behaviour using clam shells as shelter. However once humans began discarding large numbers of coconut shells, they inadvertently created a steady supply of lightweight octopus portable armour - the perfect tools to protect against fish attackers on the underwater mud flats they call home.

Julian and Mark's paper ‘Defensive tool use in a coconut-carrying octopus', co-authored by Tom Tregenza of University of Exeter, Cornwall, appears in the scientific journal Current Biology this week.