The Loch Ness Monster: From the Surgeon's Photograph to the DNA Survey

Loch Ness is a long, narrow, very deep freshwater lake in the Scottish Highlands, about 23 miles long and more than 700 feet deep at its deepest, its water stained dark by peat so that visibility below the surface is poor. It holds more water than any other lake in Britain. It lies in the Great Glen, a valley scoured by glaciers, and it took its present form after the last ice age, about 10,000 years ago.

The loch's most famous early monster story is a saint's tale. In the Life of St Columba, written around the end of the seventh century by Adomnán, an abbot of Iona, Columba meets local people burying a man who had been attacked by a water beast in the River Ness, sends a companion swimming across, and drives the beast back with the sign of the cross. Whether it is read as a monster report or as a miracle story in a long tradition of saints taming beasts, it is a long way from the modern legend, which began in the 1930s and grew with remarkable speed.

In April 1933 a couple driving along the north shore of the loch, on a road that had recently been upgraded and offered clear views of the water, reported seeing a huge animal disturbing the surface. The Inverness Courier published the account on May 2, 1933, written by its local correspondent Alex Campbell, a water bailiff on the loch. That summer another couple, the Spicers, said they had seen a large creature with a long neck cross the road in front of their car and vanish toward the water.

The story spread through the British press and then around the world. Reporters arrived from London, and by the end of the year the Daily Mail had hired a big-game hunter, Marmaduke Wetherell, to track the beast down. Wetherell soon found giant footprints on the shore, but scientists at the Natural History Museum concluded they had been made with a dried hippopotamus foot, probably one mounted as an umbrella stand. The episode embarrassed Wetherell, and it set the stage for the most famous Nessie photograph of all.

In April 1934 the Daily Mail published a photograph of a slender neck and small head rising from rippled water. It was credited to Robert Kenneth Wilson, a London gynecologist who did not want his name attached to it, so it became known as the surgeon's photograph. For sixty years it was the defining image of the monster, reproduced in countless books and taken by many as evidence of a surviving plesiosaur.

Doubts grew over the decades. A 1984 analysis of the uncropped original suggested the object was only a few feet long. Then, in 1994, the researchers David Martin and Alastair Boyd made public the account of Christian Spurling, Wetherell's stepson, who had told them before he died that he had made the monster himself: a toy submarine bought from Woolworths, fitted with a head and neck sculpted from wood putty. According to Spurling, Wetherell wanted revenge on the Daily Mail for the hippo-foot humiliation; the model was photographed on the loch, and Wilson, a respectable figure, was recruited to have the pictures developed and sell them as his own. A few writers still question parts of Spurling's story, but the photograph is now almost universally regarded as a hoax.

Few lakes have been searched so thoroughly. Volunteers of the Loch Ness Investigation Bureau kept watch from camera stations on the shore from 1962 to 1972. In the 1970s the American patent lawyer and inventor Robert Rines used underwater cameras and sonar and published photographs said to show a diamond-shaped flipper, though the best-known flipper picture had been computer-enhanced and, by later accounts, retouched. In 1987 Operation Deepscan sent a line of about two dozen boats across the loch, sweeping it with echo sounders; it logged a few sonar contacts that were never conclusively identified, and nothing that looked like a population of large animals.

In 2003 a survey for the BBC used 600 separate sonar beams and satellite navigation to sweep the whole loch, with enough resolution to pick out a small buoy, and found no animal of any great size. Skeptics also point to the biology. A population large enough to survive for generations would need many animals; the loch does not produce enough food to support many large predators; a plesiosaur, extinct for 66 million years and air-breathing, would have to surface often and would be seen constantly; and the loch itself was under ice until about 10,000 years ago.

In June 2018 a team led by Neil Gemmell, a geneticist at the University of Otago in New Zealand, collected about 250 water samples from sites around Loch Ness and at different depths. Every living thing sheds traces of DNA into its surroundings, in skin cells, scales, mucus and waste, and this environmental DNA, or eDNA, can be sequenced to build a list of what lives in a body of water without anyone having to see it.

When the team presented its results in September 2019, it reported no reptile DNA at all, so no sign of a plesiosaur, and no trace of sturgeon, giant catfish or Greenland sharks, all of which had been suggested as explanations. What it did find, at almost every sampling site, was a striking amount of eel DNA. Gemmell was careful about what that meant. DNA cannot show how big the eels are, and nothing in the data pointed to eels of monster size; a giant eel could not be completely ruled out, he said, but the survey offered no evidence that one exists. For the first time, a single study had sampled the biology of the whole loch at once, and what it described was the wildlife of an ordinary Highland lake.

Most people who report seeing the monster are sincere, and many are describing something real: boat wakes that persist long after the boat has passed and roll across a calm surface as a line of humps; standing waves and wind slicks; swimming deer or birds seen low against the water; floating logs and mats of vegetation; and large fish. Distances and sizes are very hard to judge on open water with no reference points, and the loch's dark, still surface is ideal for turning an ordinary disturbance into a shape.

Nessie has also become part of Scotland's identity and of the economy around the loch, with exhibitions, boat trips and a steady stream of visitors hoping for a glimpse. That has not stopped the searching; it has made the searching part of the attraction. The monster's history is a useful lesson in evidence. The most persuasive picture was a toy, the most thorough survey found eels, and the reports keep coming anyway, because a dark lake in the Highlands is exactly the kind of place where people expect to see something.