Mythical creature – The Water horse.

The term "water horse" was originally a name given to the kelpie, a creature similar to the hippocamp, which has the head, neck and mane of a normal horse, front legs like a horse, webbed feet, and a long, two-lobed, whale-like tail. The term has also been used as a nickname for lake monsters, particularly Ogopogo and Nessie. The name "kelpie" has often been a nickname for many other Scottish lake monsters, such as each uisge and Morag of Loch Morar and Lizzie of Loch Lochy. Other names for these sea monsters include "seahorse" (not referring to the seahorse fish) and "hippocampus" (which is the genus name for seahorses).

Whilst most Scottish/Celtic folklore places the water horse in a loch (particularly a loch that is famous for a lake monster, such as Loch Ness, Loch Morar or Loch Lomond), some Breton and Cornish tales of water horses place them in the ocean, making them sea monsters.

Most Highland loch have some kind of water-horse tradition, although a study of 19th-century literature of the time showed that only about sixty lochs and lochans merited a mention out of the thousands of bodies of water in Scotland. The water horse that was reputed to inhabit Loch Ness gained the most mentions in Highland literature.

The Breton King Gradlon's magical "horse of the sea" Morvarc'h (whose name literally means "sea horse" in Breton) was said to have the ability to gallop upon the waves of the sea, in a similar fashion to the water horses of Cornish legend.