The nose of the sperm whale, which is the largest nose on the planet, takes up about 33% of their body length.
This nose includes the spermaceti organ, an oil filled cask,
which is specialized as the world's largest sound producing mechanism.
Photo: Chris Johnson
March 15, 2001
The Acoustic Realm of the Sperm Whale - Part I
This is Genevieve Johnson speaking to you from Kimbe Bay in the Bismarck Sea, Papua New Guinea.
This is just a sample of the sounds we have been hearing everyday, since leaving Kavieng.
[ sound recording of a group of sperm whales recorded from the Odyssey ]
Over the last week and a half, the Odyssey crew has been in constant visual and acoustic contact with sperm whales. We have been surveying a relatively unknown area in terms of whale and dolphin species, and have been thrilled to encounter several groups of sperm whales. Some have been in tight clusters of eight to ten animals, others spread out in small groups of three and four, as well as several individuals in loose associations.
It has been particularly interesting to collect acoustic recordings, or vocalizations from these diverse groups, differing in compositions of abundance, sex and age.
Visiting scientist Benjamin Kahn explains the acoustic realm of the sperm whale:
Sperm whales are highly vocal. They emit loud, regular clicks almost continuously while underwater, which is close to forty- five or even fifty minutes out of the hour. To illustrate how important sound is, you just have to look at the sperm whale's anatomy. Their nose, which is the largest nose on the planet, takes up about 33% of their body length. This nose includes mostly the spermaceti organ, an oil filled cask, which is specialized as the world's largest sound producing mechanism.
A couple of sounds that the sperm whale produces can be categorized, for instance, the clicks are very common. Sperm whales have a high degree of acoustic specialization. You could say that sperm whales 'see' their ocean home through sound information. In the water, sound travels five times faster than in air, so it is quite an effective way to become more aware of your environment.
Their routine vocalizations are clicks. These are very monotonous, usually about two clicks per second and they are precisely spaced out, timed to perfection.
[ sound recording of a sperm whale click ]
We think the clicks have an ecolocative function. A large group of sperm whales, for instance when clicking together and out of sink usually, sound like a horse race; like an underwater derby.
[ sound recording of a large group of sperm whales ]
These clicks are a form of sonar, and assist the whales in finding, tracking and catching squid, or other preferred prey. Presumably the clicks also convey information on the relative position of each animal as the sperm whales forage in a cooperative manner. Sperm whales usually forage in line, sweeping the mid ocean water, along the same course, like a squadron of submarines. In addition, clicks could relay information on prey abundance.
Clicks will occasionally turn into a string of fast 'creaks', sounding very much like the creaking door of a haunted house. These sounds function most likely, as a short range, prey location devise, fine tuning for capture. While we are on watch in the evenings, this is one of our favorite sounds to listen to. It's quite spectacular.
[ sound recording of a sperm whale 'creak' ]
Visiting Scientist, Benjamin Kahn, joins the Odyssey during this current research leg in the Bismarck Sea.
Photo: Chris Johnson
Perhaps the easiest way for visual creatures like us to comprehend this odd world of bioacoustics, is to think of each click as an acoustic strobe. A regularly fired strobe allows you to assess your environment in evenly spaced bits of information. Rapid strobing increases the information and gives you a better resolution of your surroundings.
Another, perhaps more intriguing vocalization of sperm whales, are vocalizations that are labeled codas. Codas are defined as temporal codings of click patterns, a fancy description of something that is very akin to a Morse code. Codas are used for communication, for instance, they are most frequently heard when whales are at or near the surface and when whales meet. Whales may then react to each other acoustically, most often between animals in close range. Interestingly, codas often elicit silence from distant clicking sperm whales, perhaps indicating that they are paying attention.
[ sound recording of a sperm whale 'coda' ]
Codas are a unique form of communication. As far as we know, it is a type of Morse code as I mentioned, it's a 'yes', 'no' series. Not so far removed from a digital language, made up of ones and zeros, Some codas seem to be more popular in certain areas than others, so in a way you can use codas to examine regional connectivity and population structures on a large scale. For example in the Galapagos, a frequently heard coda, especially when initiating exchanges, the opening coda, is the 'give me five coda'. This is a five click series, often heard before other codas follow, these other codas could be an eight-click coda or a seven-click coda, and then the communication becomes quite complex.
In the waters of Papua New Guinea, we have also identified a favorite coda so far, and we've called it the 'shave and a haircut' coda. This is a really nice one that we have heard for several days now, whenever we hear it, it brings a smile to our face and usually a tap dance from someone in the wheelhouse. Sometimes the whales respond with the same coda, and this can go on for quite a long period of time. Sometimes they will respond with a different coda and then a different one yet again, and then you get a whole series of codas, which can be a very exciting exchange.
[ sound recording of a sperm whale exchange ]
Log by Benjamin Kahn & Chris Johnson
Gordon, J. 1991. Evaluation of a method for determining the length of sperm whales (Physeter catadon) from their vocalizations. J. Zool. 224: 301-314.
Gordon, J. 1998. Sperm whales. Voyager Press, USA. 72pp.
Kahn, B., H. Whitehead and M. Dillon. 1993. Indications of density-dependent effects from comparisons of sperm whale populations. Mar. Ecol. Prog. Ser. Vol. 93: 1-7.
Watkins, W. 1977. Acoustic behavior of sperm whales. Oceanus Vol 20 (2):50-58.