"Cattle of the sea." The fairy cattle or sea cattle of Scottish folklore. They are said to inhabit fresh and salt water on the west coast of Scotland. They are usually hummel (hornless) and of dun color, except those near the Isle of Skye who are red and speckled or black. If the bulls of the crodh mara mate with mortal cows it will improve the stock. See also gwartheg y llyn, cro sìth, tarbh uisge.
- MacKillop, James. (2004). Dictionary of Celtic Mythology. New York: Oxford University Press, Inc.