Listening to sperm whale sonar

Amazing.

A few years ago in the Gulf of California, we found ourselves surrounded by a pod of female sperm whales sleeping peacefully like massive logs in a calm sea. One, followed closely by a seemingly protective companion, had a baby so new that it still trailed an umbilical cord as it swam with tail flukes not fully unfurled. Naturalist Carlos Navarro slipped into the water with his camera. He recorded these sounds being produced by the sperm whale he was filming at close range.

Sperm whale. Photo: Carl Safina

Dolphins and toothed whales’ jaws, skulls, and brains are designed for the production and fine analysis of sound.

The clicks in this recording are different from the calls many dolphins and whales also make. The clicks are sonar; their returning echoes give the whale an aural “image” of objects in the water. Toothed members of the cetacean order, such as dolphins, porpoises, killer whales, and sperm whales, produce sound in their heads and project it outward through their foreheads, which are filled with special fat to create a sound lens.

Baby sperm whale. Photo: Carl Safina

I think of it as the audio version of wearing a headlamp; our own brain analyzes the returning light to give us a visual image. They do a similar thing, but they do it with sound that they produce, and the reflected thing their brain analyzes are echoes.

They can see, and we can hear, but we greatly emphasize the analysis of light and vision to orient and navigate and locate things; they emphasize sound.

Sperm whales. Photo: Carl Safina

Carlos says that from underwater the clicks sounded very intense; he could feel his body vibrating as the whale scanned him. Because Carlos is not a squid, he had nothing to fear.

My deep blue thanks go to Lindblad Expeditions for access to the sea of whales, and to Carlos Navarro for sharing his recording.