Have coconut, will travel
The video clip is engrossing and entertaining – even for people who do not find octopuses attractive. In one shot, a small veined octopus sits in half a coconut shell, pulls another half over the top, and peers out like a child playing peekaboo.
Further sequences show the ungainly movement as octopuses hitch up coconut shell halves underneath them, drape their arms over the sides, and take off walking along the sea floor.
The behaviour of these photogenic animals is significant. It's the first known example of tool use in invertebrates, animals without backbones – and it has disrupted the life of La Trobe PhD graduate Julian Finn who works at Museum Victoria.
When a release on the coconut-carrying octopuses was mounted on the web last December by the Museum, the traffic to view the video pushed the website to its limit. And Dr Finn spent nearly two days non-stop on the phone answering media inquiries from across the globe – Canada, France, the US, Japan, and Finland among others. Articles appeared almost everywhere, including the Himalayan Times, the Hawaii Star Bulletin and the Seychelles Weekly.
The BBC website featuring the story and video received more than 1.3 million hits. YouTube posted more than 1 million. But it all started by chance. Dr Finn stumbled on the coconut-carrying individuals while tracking a completely different octopus.
While his La Trobe doctoral thesis is on paper nautilus and he is now studying octopus behaviour in Port Phillip Bay, Dr Finn has financed much of his research by acting as a scientific consultant to film and video crews working on wildlife documentaries.
'I was assisting with a BBC documentary looking for mimic octopus in the shallow, silty environments of northern Sulawesi, when I came across a half coconut shell on the sea bottom. It moved, and underneath was a little veined octopus peeking out. Then the octopus stuck out an arm, climbed out from under the shell, flipped it over, and ran away.'
For the next ten years, Dr Finn and Museum colleague Dr Mark Norman accompanied other crews to Sulawesi and to Bali, spending more than 500 hours underwater and studying the coconut-carrying behaviour of more than twenty individuals of the veined octopus, Amphioctopus marginatus. But it was only when they talked to Dr Tom Tregenza of the University of Exeter that they became aware of the significance of what they had seen.
The ability to use tools has long been regarded as mark of intelligence. It was originally held that only humans used tools, but then it became apparent that other primates did so, as well as an expanding array of mammals and birds.
A genuine tool
Recently, for instance, there has been a lot of work by groups at the universities of Auckland and Oxford on how the New Caledonian crow fashions and employs tools in the pursuit of food. But no-one had reported tool use in invertebrates until Dr Finn, Norman and Tregenza published their recent paper on the activities of the veined octopus in the journal, Current Biology.
The point is that, unlike hermit crabs which live in borrowed shells permanently, the veined octopus carries a coconut shell with it – at considerable cost in terms of energy and restricted movement – so that it can occasionally deploy it for defence against potential predators. The shell provides no benefit until it is used. It is a true tool.
The behaviour may have started, Dr Finn thinks, with octopuses crawling into large clam shells to avoid being eaten. But when humans began discarding light, durable, half-coconut shells into the water, the octopuses appropriated them, he says. And now they've provided the web with a memorable video clip.
See the video of the octopus on the BBC website.