Defensive tool use in a coconut-carrying octopus

Abstract

The use of tools has long been considered a hallmark of cognitive sophistication, observed in primates, mammals, and birds. However, among invertebrates, the acquisition and later deployment of items has not been reported until now. This study documents the repeated observation of veined octopuses carrying around coconut shell halves, assembling them as a shelter only when needed. These octopuses were observed traveling over considerable distances carrying stacked coconut shell halves, walking on their arms in a unique and previously undescribed “stilt-walking” gait. This gait is less efficient than normal locomotion and provides no immediate protection, suggesting that the octopuses carry the shells for future use as a shelter, rather than for a specific task. The collection and use of objects by animals likely forms a continuum, with the definition of tools constantly debated. This finding suggests that marine invertebrates engage in behaviors previously thought to be the exclusive domain of humans. – AI-generated abstract