Nearly all deep-sea divers can recall a time when they experienced temporary insanity among the sea anemones. Some have tried to chat with fish; others had to be dragged to the surface by companions whom they mistook for kidnapers. During a videotaped expedition, one man floated down to the seabed to sit next to a flower. He tore off the petals, chorusing, "She loves me, she loves me not." When he later watched the tape, he was bewildered to see himself pulling the legs off a crab.
A condition called nitrogen narcosis is the likely culprit behind such underwater weirdness. It often begins as a fuzzy-headed feeling. "You know when you've had a couple of drinks, and you realize if you have any more you'll be gone?" asks Sam Harding, a researcher at the Diving Diseases Research Center. "It's like that."
Scientists can't pinpoint a specific depth where the onset of nitrogen narcosis occurs. Harding describes its chemical causes as "wonderfully elusive," which only adds to the ailment's appealing mystery. But they do know that it involves the dissolution of nitrogen into cell membranes, which they suspect stops or slows nerve cell communications.