TAHOE CITY - A scientific expert on Lake Tahoe said the lake's version of the Loch Ness Monster - Tahoe Tessie - is most likely a mirage caused by temperature changes in the water.
Dr. Charles Goldman, a limnologist and the foremost expert on Lake Tahoe, discussed a recent trip to Loch Ness and possible explanations for such sightings.
Goldman said, as with Loch Ness, most sea monster sightings tend to be in deep, cold lakes which produce mirages brought on by temperature changes.
"That is why people see things that really don't exist," he said.
The difficulty with verifying the existence of lake monsters, said Goldman, "is that you can prove something is there, but you can't prove something is not there." Thus far, the search for a lake creature has yet to produce any concrete evidence, he said
In August, Goldman was invited to study Loch Ness by Professor Robert Rains, head of the Applied Science Institute at the Massachusetts Institute of Technology. Rains, a firm believer in the Loch Ness monster, used sonar in the 1970s to take strobed photos of "Nessie."
These photographs determined the creature was 20 to 30 feet long and had humps. While other photos of Nessie, such as a famous one showing a long-necked creature rising out of the water, have been determined to be hoaxes, Goldman said Rains' photos are more difficult to discount. One is of a flipper "that looks terribly authentic," according to Goldman, and another shows a 20-foot-long body and head.
Twenty years ago, Goldman held a conference at the University of Nevada, Reno, on "Unidentified Swimming Objects." A number of scientists testified they had seen Tahoe Tessie. All sightings have one thing in common, said Goldman - no one ever sees the head or tail, only dark objects in the water.
Based on this, Goldman decided to conduct a number of experiments. He created a photo of Tessie by capturing the splash from rocks thrown in the water. Another photo shows what looks like a series of humps in the lake, but which are only waves.
"You have a flat lake with no boats visible, but boats did pass hours before, and the waves come back and amplify," explained Goldman.
However, Goldman also gave another possible explanation for Tessie spottings. While the 11,000-year-old lake is too young to have a prehistoric creature swimming in its waters, it could be the home of a very large sturgeon.
Sturgeon have been known to reach 1,500 pounds and live for up to 100 years. They could have been introduced with fish stockings over the years, said Goldman. With more than 5,600 prey fish in Tahoe, a massive sturgeon would have plenty of food.
