Payne discovered that elephants use ultra-low frequencies to sing songs that are inaudible to the human ear. Female elephants sing low-frequency songs of up to 45 minutes while in heat, attracting males from surrounding regions. The trumpeting sounds that elephants make are quite separate from the more mysterious low-frequency vocalizations, which range from about 5 herz to just above 14 herz . Among the keenest musical communicators in the animal kingdom are dolphins. While much remains to be learned, a study done by the Dolphin Institute found that dolphins can recognize similar tones spanning more than two octaves.
Songbirds can recognize the same type of melodic sequence within the same octave.
Dolphins spontaneously recognize the same pitches across the octaves in the same way we can recognize a woman's voice vs. a man's voice. Pack says that dolphins use broadband clicks for echolocation. Dolphins will imitate the signature whistle of close companions. Mothers, when separated from young, may mimic their youngster's signature whistle to call them, and close companions mimic each other when they're separated. Frog filters At the other end of the size spectrum, sound frequency also appears to be a critical element in frog and even insect communication.