Most of the sounds Sperm Whales produce are clicks, from less than 100 Hz to 30 kHz, the majority of energy of which is in the 2 to 4 kHz and 10 to 16 kHz ranges. The click repetition rate varies widely.
The illustration below is a sound spectrogram of a recording made by BRP scientist Kurt Fristrup in the Azores in August 1996. This expedition was designed to locate giant squid, Architeuthis, by tracking the sperm whales which prey on them.)
There are three sperm whales vocalizing in this 6-second recording: the 10 clicks of the louder whale are highlighted in pink. To hear the recording, click on the spectrogram.
Sperm whales also produce concentrated series of clicks, known as "codas"
The illustration below is a sound spectrogram of a 9.2-second recording made on the same day. Again, several whales are clicking steadily, while another is producing the bursts of faster clicks higlighted in the green regions of the spectrogram. To hear the recording, click on the spectrogram.