Thanks Daffynition. This is yet another in a long line of implausible "explanations" which will, of course, be saddled on as the correct one by the skepticultists. Cryptobiology ping.
http://www.pbs.org/wgbh/nova/ancient/legend-loch-ness.html
When the Romans first came to northern Scotland in the first century A.D., they found the Highlands occupied by fierce, tattoo-covered tribes they called the Picts, or painted people. From the carved, standing stones still found in the region around Loch Ness, it is clear the Picts were fascinated by animals, and careful to render them with great fidelity. All the animals depicted on the Pictish stones are lifelike and easily recognizable — all but one. The exception is a strange beast with an elongated beak or muzzle, a head locket or spout, and flippers instead of feet. Described by some scholars as a swimming elephant, the Pictish beast is the earliest known evidence for an idea that has held sway in the Scottish Highlands for at least 1,500 years — that Loch Ness is home to a mysterious aquatic animal.
