There is some debate as to whether the Kelpie and the Each Uisge are in fact the same creature. Most sources class them as identical. However, the Kelpie, an aquatic species of shapeshifter native to Scotland, is generally thought to be somewhat less powerful than its cousin, the Each Uisge, although still quite dangerous in its own right.
The Kelpie prefers streams, rivers, and small, fast-moving tributaries, while the Each Uisge, or water horse, is native to the larger freshwater lochs of Scotland, and to the sea.
Often appearing as a lost pony, the Kelpie will entice children to pet or ride it. Once the victim is astride the false pony, however, it draws its unfortunate rider down to the river-bottom, in order to consume its prey in peace.
A Kelpie may be caught, if it can be bridled and harnessed. A captive Kelpie is extremely valuable, due to the fact that once harnessed, it will work tirelessly, tilling even the hardest ground. However, the farmer must be prepared for the grisliness of its care and keeping, because at the end of the day, even the domestic Kelpie must eat human flesh.
The Each Uisge typically appears in the form of a fine horse, or, if the creature has a desire to lure maidens, as a handsome young man. When in the presence of water, the skin of the Each Uisge becomes incredibly sticky, adhering to the body of its rider and making escape impossible. Although similar to the Kelpie in many ways, the Each Uisge is considerably more ravenous, consuming not only children, maidens and grown men, but also sheep and cattle.
In any form, both the Kelpie and the Each Uisge may be identified by their perpetually dripping hair. Thus, it may be considered prudent to avoid wet strangers, and to refrain from riding any mysterious unsupervised horse.