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Tool use in octopuses discovered
by Jaspreet Virk - December 15, 2009 - comments
The octopus is seen arranging the shell in a manner that the concave surface is uppermost. It further extends its arms around the outside and uses them as rigid limbs. It carries the shell in a lumbering gait defined as ‘stilt walking'
New York, December 15 -- In an activity never associated with marine invertebrates, scientists from Australia have discovered octopuses carrying coconut shells for shelter, an evidence of tool use in an invertebrate.
In a study named “Defensive tool use in a coconut-carrying octopus”, published Monday in Current Biology, the scientists have reported an example of tool use in veined octopuses.
Cognitive ability of marine invertebrate revealed
Julian K. Finn and and Mark D. Norman from Museum Victoria, Melbourne have filmed a veined octopus.
The invertebrate animal is seen selecting coconut shell halves, emptying them out and carrying them under their body and later using them as shelter or a protective shield.
The octopus is seen arranging the shell in a manner that the concave surface is uppermost. It further extends its arms around the outside and uses them as rigid limbs. It carries the shell in a lumbering gait defined as ‘stilt walking’.
Over the years, some species of octopuses have been observed engaging in activities like prey manipulation, burying and den excavation, arm dexterity, den barricading with rocks/corals etc. But these activities have not been defined as genuine tool use because they are more instinctive than calculated.
“The fact that the shell is carried for future use rather than as part of a specific task differentiates this behaviour from other examples of object manipulation by octopuses, such as rocks being used to barricade lair entrances,” stated the biologists in their study.
The evidence of tool use is further strengthened by the fact that the octopus carried the shells and assembled the separate parts to create shelter.
About the study
Between 1999 and 2008, Finn and his colleagues undertook more than 500 dive hours off the coasts of Northern Sulawesi and Bali in Indonesia.
During this time frame, they studied the behavior of more than 20 veined octopuses. They emerged to be active on the sea floor, carrying empty coconut shell halves or other human refuse.
On four occasions, the octopuses were seen traveling a distance of about 20 m while carrying empty coconut shells beneath their body, arranging the shells, emerging from the cover of one or two shell halves etc.
The discovery of the octopus carrying coconut shells has indeed revealed that even marine invertebrates engage in activities that were only associated with humans.