Tales of the lake-dwelling creature can be traced to stories told by members of the Washoe and Paiute tribes in the mid-19th century, stating that the creature resides in an underwater tunnel beneath Cave Rock, and sightings have continued into modern day.
Sightings describe Tessie as being between 10 and 80 feet long, having a large, serpentine body "as wide across as a barrel," and coloration ranging from jet black to turquoise. Its skin is usually described as smooth, despite having reptilian features.
In the 1950s, two off-duty police officers out on the lake reported seeing a large, black hump rise from the water, and keep speed with the boat, going over 60 mph (97 km/h).
According to an anonymous witness on Weird California, "Myself, along with 3 others watched a large serpent-like creature feeding/hunting in a school of large trout. It was in the middle of winter of 1979 off the dock at Homewood. It was about as big around as a telephone pole and maybe 30'-60' in length from what we could see of it. It didn't swim like a snake (side to side). It was diving up and splashing down with its head/neck? into the school of fish, which were leaping out of the water ahead of it. We were speechless for several minutes afterwards." In the 1980s, two fishermen reported seeing a 15-foot-long (4.6 m) serpent pass underneath the surface of the water, near Cave Rock.
Several weeks after, two divers reported finding an underwater cave, and a creature shot out, leaving the silt stirred. Where the creature had been, there were two large fin-prints.
Sometime in the late 1990s, a kayaking instructor reported seeing a glance of what looked like a green two-person kayak flip over and immediately sink. When he approached the area in a speedboat, there were no traces of the kayak, and his students did not report flipping over at any time.
In 2004, an off-duty bartender on the Tahoe Queen took a picture of a black hump in the water, which he claims is the top of the creature's head. In 2006 a family vacationing near Tahoe sited a large, black, scale lacking creature appearing similar to a sturgeon with an upturned white nose near Lake Tahoe's dark shore. However the creature moved up-and-down like a Mammal instead of side-to-side like a reptile.
There has been rumored Tessie footage, which is reportedly being analyzed before being released to the public.
There have been many theories surrounding Tahoe Tessie, the most popular being that it is either a Plesiosaur, Icthyosaur or a Mosasaur, due to fossils of the creatures being found in the Surrounding Nevada Desert, and Sierra Nevada mountains. These theories are quickly dismissed by many Tessie experts, stating that the lake was formed in the last Ice Age, long after the creatures went extinct. Other theories say that it may be anything from a population of Sturgeon, to a new species of Freshwater eel.
In Popular Media
Tahoe Tessie is a popular logo for many Tahoe-based companies, with a cartoon version being in many children's picture books, and a popular character featured in local newspapers. There even used to be a local museum and hotline, but both recently closed.