The researchers very interesting report is published in the December 14, 2009 issue of the journal Current Biology under the title “Defensive tool use in a coconut-carrying octopus.” [Current Biology, Volume 19, Issue 23, R1069-R1070, 15 December 2009, doi:10.1016/j.cub.2009.10.052]
The authors are Julian K. Finn (Museum Victoria, Melbourne, Australia), Tom Tregenza, (La Trobe University, Bundoora, Australia), and Mark D. Norman (University of Exeter, Penryn, United Kingdom).
According to the abstract of the group’s Current Biology article, “The use of tools has become a benchmark for cognitive sophistication. Originally regarded as a defining feature of our species [Homo sapiens], tool-use behaviours have subsequently been revealed in other primates an a growing spectrum of mammals and birds.”
The three researchers define a tool as "an object carried or maintained for future use.” According to that definition, the behavior of the veined octopus is the first documented case of tool use in invertebrates.
Thus, the group reports that these abilities have previously been seen only in vertebrates. However, now this discovery adds an invertebrate, the veined octopus, to the list of tool-use animals.
The veined octopus will intentionally carry one coconut shell half (or two halves) to a specific location where it will assemble the two into a protective shelter.
If they have only one half, the octopus will turn the coconut shell half over and hide underneath it. If they have two halves, then they will assemble the two halves into its original coconut form (as a ball-like structure) and hide inside it.
See the video of the octopus carrying the coconut shelf half in the YouTube video “Coconut-carrying octopus.”
Page two continues with additional information on this newly discovered abilities of the veined octopus.
The veined octopus (scientifically known as the species Amphioctopus marginatus) is also called the coconut octopus.
The researchers call the movement of the octopus while carrying a coconut half “stilt walking.”
The 12-15-2009 ScienceDaily.com article “Coconut-Carrying Octopus: Tool Use in an Invertebrate,” describes the stilt walking activity as “In it, the soft-bodied octopus spreads itself over stacked, upright coconut shell "bowls," makes its eight arms rigid, and raises the whole assembly to amble on eight "stilts" across the seafloor.”
Mark Norman, one of the authors of the study, stated, "There is a fundamental difference between picking up a nearby object and putting it over your head as protection versus collecting, arranging, transporting (awkwardly), and assembling portable armor as required." [ScienceDaily]
Julian Finn, another author of the study, adds, "While I have observed and videoed octopuses hiding in shells many times, I never expected to find an octopus that stacks multiple coconut shells and jogs across the seafloor carrying them.” [ScienceDaily]
Finn adds, "I could tell that the octopus, busy manipulating coconut shells, was up to something, but I never expected it would pick up the stacked shells and run away. It was an extremely comical sight -- I have never laughed so hard underwater."
Page three concludes.
During their researcher the scientists spent about 500 diving hours under the water. During this time they observed twenty veined octopuses.
On four separate occasions they observed octopuses traveling up to 20 meters (66 feet) while carrying coconut shell halves.
They concluded, "Ultimately, the collection and use of objects by animals is likely to form a continuum stretching from insects to primates, with the definition of tools providing a perpetual opportunity for debate."
"However, the discovery of this octopus tiptoeing across the sea floor with its prized coconut shells suggests that even marine invertebrates engage in behaviors that we once thought the preserve of humans." [ScienceDaily]
For additional information on this interesting study of octopus behavior, please read the Museum Victoria article “Tool use in Veined Octopus.”
The article also includes a video of the coconut-carrying octopus.