Traditional descriptions of the Gaelic water-horse display intriguing similarities to the mysterious ‘Pictish Beast’ or ‘Swimming Elephant’, the most ubiquitous yet least recognisable creature of our symbol-stones, which is dateable to c. AD 700. This paper sets out a typology of water-horse stories and attempts to show that they can be dated to that period. It then considers whether the iconography of the Beast, the ‘head-lappet’ in particular, can be explained in terms of the ethnography of the water-horse, whose principal attribute is its cap or magic bridle. The Torrs Pony-Cap, Adomnán’s river-monster and the ‘kelpie’ of Lowland tradition are taken into account, and it is suggested in conclusion that the water-horse and kelpie are Gaelic and Anglo-Norman reflexes of a leading Pictish deity, the guardian of their otherworld.
