"The wolf howl is a long, low, mournful sound. It is continous - from about half a second to 11 seconds in lenght. It consists of a fundamental frequency, between 150 and 780 cycles per second, and contains up to 12 harmonically related overtones. The pitch remains constant or varies smoothly, and may change direction as many as four or five times. Total intensity does not vary greatly throughout. Yet there is much variation in the howling of different wolves"
in - "The language and music of the wolves" - 1971 USA American Museum Of Natural History
