The sperm whale (Physeter macrocephalus) is a marine mammal species, order Cetacea, a toothed whale (odontocete) having the largest brain of any animal..." rel="shadowbox;height=800;width=1000">Sperm Whale [2] (Physeter macrocephalus) buzz or creaks. Closely spaced Marine mammals, such as whales, dolphins, and porpoises, are much more dependent on sound for communication and sensation than are land mammals, because other senses are of limited effectiveness in water..." rel="shadowbox;height=800;width=1000">clicks [3] with the rate of clicking accelerating over the course of the creak, which is an indicator of a foraging phase of a dive. Recordings courtesy of Dr. Peter Tyack and Woods Hole Oceanographic Institution (WHOI [4]).
Links:
[1] http://csi.whoi.edu/audio/spermwhale-audio
[2] http://en.wikipedia.org/wiki/Sperm_whale
[3] http://en.wikipedia.org/wiki/Whale_sounds
[4] http://www.whoi.edu
[5] http://csi.whoi.edu/aquatic-mammals-audio