Tools aren't just for vertebrates anymore. The veined octopus has been spotted lugging around coconut shells to serve as mobile shelters, the first time scientists have observed tool use in an invertebrate species.
Humans living on the Indonesian coast frequently discard halved coconut shells in the ocean, and it turns out that their eight-legged neighbors have been making use of them. Researchers have filmed veined octopi, Amphioctopus marginatus, moving the shell halves by placing their bodies inside the hollowed-out portion, draping their legs over the edges, and bringing the shells along for the ride. When the coconut-carrying octopus feels threatened, it will pull the half shell over its body (or sometimes pulls two halves of a whole coconut over itself), and wait inside their armored home until the threat passes.
Veined octopi have been seen hiding out inside coconut shells before, but researchers hadn't realized that the creatures were deliberately carting the shells around for this purpose. Marine biologist Julian Finn of Melbourne's Museum Victoria caught a lucky glimpse of a veined octopus carrying and using the shells, and has since filmed four octopi doing the same thing.
Finn and other researchers argue that this is the first reported use of tools by an invertebrate species, as this is a sophisticated, costly behavior in which an animal manipulates an object for future plans. While others argue that it does not fit the standard definition of tool use, since the octopus isn't using the object to act on another object, it may still require a sophisticated level of cognition, and we should investigate what makes such foresight possible.
Octopuses use coconut shells as portable shelters [New Scientist]