Even played at 10 times its usual speed, the rumble of an angry bull elephant was difficult for students to hear. But they could feel it through the soles of their feet as it pulsed through Lyte Auditorium at Pennsylvania's Millersville University, where several hundred elementary, junior high and high school students gathered to listen.

It was a sound that no human ear had ever heard before Katy Payne, a renowned whale biologist, decided on a whim in 1984 to spend a few days with baby elephants at an Oregon zoo. "It wasn't a very intellectual decision," she recalled during an interview preceding her talk with students. "I just wanted to see them."

It wasn't what she saw, but what she felt, that changed the course of Payne's study. "I felt a throbbing in the air near the elephants," she said. "I remembered how the air used to throb ... when I sang in the choir, when I sat near the church organ."

She returned to the zoo with some colleagues and recording equipment to capture the sound. Although no one could hear it, the tapes -- played back at a high speed to raise the octave levels of sound -- revealed a new dimension of animal communication. "No one had ever listened to infrasound in land animals," she said. Whale song, which she had studied for years with her husband, Roger Payne, also use subsonic frequencies to communicate over vast distances -- sometimes "talking" to whales on the opposite side of the ocean basin.

Without the superconductive ocean water, elephant sounds travel less distance. Still, she said, this explains the pattern of movement and mating rituals for elephants over several miles. For instance, she said, female elephants are fertile for only two or three days every four years. During that brief span, the females produce a low sound, inaudible to humans, that draws the attention of every male elephant in the region. "They need to find the males fast," she explained. "It is really quite remarkable."

Payne has concluded seven African expeditions to study elephant communication prior to her visit to Millersville in 1997. Meteorologists have discovered a predictable temperature inversion which greatly expands the distance infrasound can travel, she said. Although the inversion is a global phenomenon, it is greatly enhanced on the African savanna. Sounds which previously covered approximately 30 square kilometers will travel closer to 300, she said. Studies indicate that elephants are attuned to this window of opportunity and have tailored their daily schedules to take advantage of it.

Payne studied music as an undergraduate at Cornell University. Today, she isn't sure if that interest led to her fascination with animal communication. "You never know which is the cart and which is the horse," she said. "But I love sound. I'm fascinated by human sound and animal sound."

Payne said she hoped to impart some sense of urgency about the elephants' fate to students. "They've got it made -- except when they're confronted by a predator who can mass-kill," she said. "It was only 10,000 years ago that we had elephants in this part of the world." Those that remain in Africa and Asia are "going fast," she added. "Pretty soon there won't be any elephants."