This article suggests that the rare motif on Breton menhirs often interpreted as an axe (of ‘Mané Rutual’ type) or an axe-plough, could be the representation of a whale, and that if so, this might be a mythic creature. The character of myth and narrative is considered. It is mooted that Late Mesolithic people or their immediate descendants could have been responsible for the erection of such menhirs. The juxtaposition of the suggested whale motif with versions of animals with curved horns on the broken menhir of La Table des Marchand and Gavrinis raises the possibility of alternative or competing myths and creation stories. Other representations of natural creatures in the Mesolithic and Neolithic in Europe are briefly noted, and the possible importance of myth in the Mesolithic–Neolithic transition of northwest Europe is discussed.