Sex was unusually exciting yesterday.

A group of at least six male students sang, shouted or disrobed yesterday afternoon in Moore Professor of Biological Anthropology Irven DeVore and Assistant Professor of Anthropology Marc D. Hauser's Science B-29: "Human Behavioral Biology."

"For the first seven or eight minutes, it was really a three-ring circus," said an irritated DeVore.

Before lecture started, one man walked the aisles, offering non-alcoholic beer like a stadium vendor. Later, three other students wearing water polo caps and bathrobes walked down one aisle, across the front of the hall and up the other aisle, all the while yelling, "Water polo!"

The worst was yet to come.

"One guy went down the aisles saying 'Joe, your mother's on the phone.... She found your G.I. Joe. Don't worry, he's still in mint condition, but you've got to call her ASAP,'" said Daniel L. Cohen '97, the video-tape operator for the class.

After DeVore started lecturing, a student in the front stood up to ask about the course's difficulty, waving a CUE Guide and challenging the course's 2.8 difficulty rating.

Another opened an umbrella in the second row and was asked by the professor to close it because it obstructed the vision of those behind him. The student refused to do so until DeVore turned the lights down at the student's request.

About halfway through the class, two students sitting in separate areas of the lecture hall took off their shirts at an apparently predetermined time.

DeVore, noting that last year's first lecture was disrupted by a "mentally disturbed street person who looked like an older student," said he had initially thought yesterday's incident was more of the same.

"[I've had] maybe one disruption in the past, but nothing like this three-ring circus," said DeVore.

Cohen, though, said he didn't mind.

"This is nothing," Cohen said. "Last year I was showing a film for one of the astronomy classes.... There were chickens clucking in the front row."

"I thought [today's disturbance] was kinda dumb, but the professor's comebacks were pretty funny," Cohen said.

DeVore said he thought he had been singled out.

"I was told my course was chosen because Marc Hauser and I are 'cool profs' with a big class," DeVore said. "So clearly what I have to do is become less cool and more punitive in the future."