Recognizing cephalopod boreholes in shells and the northward spread of Octopus vulgaris Cuvier, 1797 (Cephalopoda, Octopodoidea)

Octopuses prey on molluscs by boring through their shell. Among the regular naticid borings, traces of cephalopod predation should be found soon on Dutch beaches. Bottom trawling has declined, and by the effects of global warming Octopus will find its way back to the North Sea where it lived before. I describe the distinguishing characters for Octopus bore holes, give an introduction into this type of behaviour, present a short history of Dutch octopuses and a prediction of their future.