Knock, knock

Natural History, Oct, 2002 by Priscilla Gadzinski

In Adam Summers's "Biomechanics" column about sperm whales ("Fat Heads Sink Ships," 9/02), he addresses the question of why a whale would seek out a collision with a ship. According to historians, whalers once called sperm whales "carpenter fish" because of the knocking noise they made. We now know the noise is used in echolocation.

Whales may have sensed the hammering of the ship's carpenter at his never-ending task of keeping the wooden vessel seaworthy. Perhaps the ship was somehow perceived as a competitor, and that's why the whales attacked not just once but kept at it.

Priscilla Gadzinski
White River Junction, Vermont