Although the recordings are still under analysis, they offer the most compelling evidence to date that the creature might actually be real. For ECHO, a Vermont aquarium and science center that opened its doors this spring on the Burlington waterfront, the timing was eerie: August is ''Champ'' month.
In addition to its ongoing ''Champ'' display, it has offered a feast of monster-related activities all month. Educator Jean Hunt has been giving a talk on cryptozoology, the science of hidden and mystery animals, each Thursday at 6 p.m. There are special children's activities and two 20-minute lectures daily, at 11:30 and again at 3, on the facts and fiction behind the phenomenon, with believers sitting on one side of the auditorium, skeptics on the other.
Vermont author Joseph Citro, who researched ''Champ'' sightings for his 2001 novel ''Lake Monsters,'' is among the growing contingent that suspects there might indeed be a lurking presence beneath the waves.
''The Indians knew it was there before [French explorer Samuel de] Champlain 'discovered' the lake, but they lived in harmony with it, even made offerings to it when they crossed the waters,'' he said.
''Probably the biggest 'Champ hunt' took place in the mid 1800s, when P.T. Barnum took an interest in the beast and put a $50,000 bounty on its head, dead or alive. Hunters came out in swarms, but luckily the money remains uncollected.''
Just to be safe, laws protecting the creature from harassment are on the books in Vermont and New Hampshire, and sightings continue.
Mike Shea, a former airline pilot who owns the excursion boat ''The Spirit of Ethan Allen,'' says he spotted Champ in 1984 with at least 80 passengers. He described a dark object about 25 feet long and three feet wide that paralleled the boat, its ''three or four humps'' causing a wake, until a speedboat headed straight for it.
''Then it turned 90 degrees to the left and dove, and the wake stopped,'' he said, ''and that's what convinced me I saw something. As an airline pilot, I'm trained to be observant, and I know what I saw.''
Von Muggenthaler, whose North Carolina-based institute, Fauna Communications Research, puts updates of its findings at www.animalvoice.com (click on ''Lake Champlain Research''), cautions that the results of the analysis may not solve the mystery.
''`What we can say is that there is a creature in the lake that produces bio-sonar,'' she said. ''We have no idea what it is.''
Diane E. Foulds is a freelance writer who lives in Burlington, Vt.
