The term 'Nessie' was created by a journalist in a newspaper article in 1933 after the first modern sighting of a monster in Loch Ness1 was reported. The oldest sighting on record dates back to 565 AD when St Columba was said to have seen a large monster in the river Ness which links the loch to the sea. Since the first newspaper report thousands of sightings have been reported on the loch and on land. Many report the long neck and head emerging from the loch, others see moving shapes and objects on the loch surface or a large beast crossing the road in front of them.
So What is it?
Over 50 images have been recorded but only six of these have stood the test of time, the others are either fakes or mis-identifications. The most famous of these images is the 'surgeon' photo taken by gynaecologist Kenneth Wilson in 1934.
His photo showed what looked like a large neck and head emerging from the loch although with nothing visible in the background a scale could never be established. It is now generally agreed that the surgeon photo was faked by using a plastic-wood model attached to a toy submarine.
In 1968 the first sonar investigation took place in an attempt to track large objects in the loch. This was unsuccessful. The second attempt in 1987, Operation Deepscan, employed 20 sonar boats and made three possible contacts between 77 and 178 metres. The latest scan was made in 1992 to build up a picture of the bottom of the loch, but no evidence of caves or anomalies were found. The pictures taken from the 1987 expedition may look impressive but questions have been raised about the high level of computer enhancement.
Many theories have been put forward to explain what is in the loch but it is a mystery to this day. The most popular of these was the plesiosaur theory. An extinct dinosaur that some believe has survived in the loch without detection for millions of years. It was only the 'surgeon' picture that held any real evidence for this theory which is now discounted by most serious researchers. The ancient plesiosaur is also an air breather and a surface dweller which makes it a very unlikely candidate. Although lots of sightings have been made of a creature resembling a plesiosaur (or at least at long neck and small head), some if not all of these have been influenced or shaped by the media.
Less Exciting Explanations
There are many less exciting explanations for the numerous sightings in the loch such as birds and deers. Otters are another candidate that could also relate to some land sightings. The loch has a wealth of other phenomena that could lend a hand in a logical explanation, such as gas bubbles arising from decomposing matter, or shifting rocks, logs and assorted debris around the water. The loch, which at its deepest measures 230 metres, can also give rise to thermoclines (cyclic temperature variation) which can also displace objects. The wakes of boats have been known to cross the loch for up to 20 minutes and have often been mistaken for Nessie. Hot summers can create a mirage effect across the loch that seems to magnify all objects2.
Other known creatures found populating the loch are eels which live on the bottom, but seem too thin to be misidentified as a monster, and seals which were videotaped in the loch in September 1998. The seals which travel from the sea via the River Ness have led others to speculate that the beast may be a whale travelling via the same route. Unfortunately the chances of a whale swimming up the river unnoticed are slim as they are air breathers and need to surface regularly.
An extinct long-necked ancestor of the whale, the zeuglodon, was also forwarded as a candidate in the midst of the dinosaur theories. Like its modern equivalent, however, this creature was also an air breather but over a 100 million years of evolution can do wonders for a species.
If there is a creature in the loch that's been popping up to keep the tourist trade alive then the best contender so far is the sturgeon. This mammoth fish which can grow up to 20ft (6m) and live for a hundred years3 would certainly account for the many 'upturned boat' sightings, but why have no carcasses been found?
The Mystery Remains
Many people doubt that there can be any unusual creature in the loch but it is worth noting that the existence of the mountain gorilla was only officially recognised in 1902. Before this time it was only known in reports as a hairy beast living in the jungle before science looked hard enough to find it. This, one of the most enduring of cryptozoology mysteries could be solved at anytime if the right photo is taken or the right evidence found, or it could remain forever a pilgrimage for Nessie hunters and the sales of many cuddly toys and postcards.