Billy Dunn and the Lake Mendota sea serpent

In 1883 William "Billy" Dunn made his living on Lake Mendota. A Madison-born professional fisherman known as "Pickerel Billy," he supplied fish to Mendota State Hospital and downtown hotels. According to the Wisconsin Historical Society, he had enlisted in the 21st Wisconsin regiment at age 12.

Friday, 22 June 1883. About 11 o'clock in the morning. Dunn and his wife were fishing some distance from shore at a spot now disputed. The 1883 report places it near "Livesey's bluff," possibly Fox Bluff on the north shore. Jay Rath, writing in Isthmus in 2013, put the couple "just off North Brearly," across the lake.

Then Dunn noticed "a black object that was moving threateningly toward him from the direction of the middle of the lake." As it neared the boat, the outlines of a large snake appeared. Its head was "reared in the air two feet or more above the surface of the water as it came darting onward toward the boat." The water was disturbed for some distance behind it. Driftless Times Media's summary of the article adds a black tongue and white spots about three-quarters of an inch long.

Dunn struck. "The oar was well aimed," the Wisconsin State Journal reported the next day. It fell across the reptile's neck and partially stunned it. Before Dunn could pull it back, the snake's coils closed around the oar.

The creature recovered, raised its head and "darted its fangs entirely through the oar." With its head held down, Dunn struck it several blows with the other oar, then took up a hatchet. The creature uncoiled. One blow severed its fangs. The body sank from sight.

The paper said the coils left marks "still visible in the hard wood." A "Chicago drummer," a travelling salesman, reportedly bought the oar for a museum. Yet on 24 July 1892 the Chicago Tribune ran the headline "Billy Dunn Still Keeps The Oar." No record shows that it exists today. Isthmus later told of an ax handle rather than a hatchet, and a serpent "with a body as large as a man's."

No scientific or government body ever examined the report. Dunn was mocked, but he "was never shy about recounting the adventure." In 1887 he guided President Grover Cleveland on a fishing trip at Maple Bluff, and Cleveland later appointed him a letter carrier. He died in 1925.

No specific explanation has been proposed for the Dunn encounter. One earlier witness hints at the debate. In an 1892 letter, W.J. Park described an 1860 sighting in which he took the creature for a log until it moved.

Dunn's serpent did not stay alone. In 1889 a sportsman off Picnic Point was nearly capsized. In 1892 Joseph W. Daubner watched a creature feeding at the mouth of the Mendota hospital sewer: "Judging from the motion of the water the body of this creature must be from fifteen to twenty feet in length." In 1899 Mrs. E. Grove, Mrs. J.J. Pecher and other women saw a serpent plunge "into the depths of the lake, making a great deal of foam."

In 1942 Charles E. Brown gathered such tales in Sea Serpents, a pamphlet for the Wisconsin Folklore Society. Brown popularised a name for the creature: Bozho, after Winnebozho, the Ojibwe trickster figure. Older still are Ho-Chunk traditions of water spirits said to keep a den near Governor's Island. Walker Jaroch of Driftless Times Media credits Dunn with "the true origins of the serpent, or at least its popularization."