The water bull, also known as tarbh-uisge in Scottish Gaelic, is a mythological Scottish creature similar to the Manx tarroo ushtey and the Irish tarbh-uisce. Generally regarded as a nocturnal resident of moorland lochs, it is usually more amiable than its equine counterpart the water horse, but has similar amphibious and shapeshifting abilities.
The water bull is said to reproduce with standard cattle, the resulting progeny distinguishable by the small size of their ears. According to some myths, the calves of water bulls and ordinary cows ought to be killed at birth by any method other than drowning – they cannot be killed by drowning – to avoid bringing disaster to the herd. Conversely, in northern areas the calves are considered to be of superior quality.