In Scottish folklore, a Lavellan, làbh-allan, la-mhalan or la-bhallan is a creature from northern Scotland.
A lavellan’s appearance is unclear and unassuming; at the very least, it is believed to be small and furry. It was generally considered to be a kind of rodent, and the name "làbh-allan" is also used for a water shrew or water vole in Scottish Gaelic. It was however, reportedly larger than a rat, very noxious, and lived in deep pools in rivers. Sibbald believed it had the head and color of a marten, while other accounts describe it as resembling a shrew or a lizard. It has bright eyes and moves very quickly.
Its poisonous abilities were legendary, and they were said to be capable of harming cattle from forty yards away. Their very breath is noxious. They are also lethal to humans, as told in one satirical song: “Let him not go away from the houses, to moss or wood, lest the Lavellan come and smite him”.
Fleming, describing the Ermine, compared the prejudice against the animal to Sibbald's account of the country people's dislike of the Lavellan; Sibbald writing that the Lavellan was common in Caithness. Thomas Pennant made enquiries about the animal while in Ausdale in the county, and it is also mentioned in the work of Rob Donn, the Scottish Gaelic poet from Sutherland.
Pennant claims the locals preserved the skin, and, as a cure for their sick beasts, gave them the water in which it had been dipped.
It has generally been assumed that the lavellan is a demonization of the water shrew, also known locally as water mole or blind mouse. The shrew’s saliva is mildly toxic but nowhere near as virulent as the lavellan’s. Harvie-Brown and Buckley, on the other hand, propose that the common lizard – brownish in color, bright-eyed, swift, and unfamiliar – was the originator of the lavellan. It may well be a combination of both.