The Acoustic Properties of Whale Song

i-d66e2e805f86d6328b490e2b7105b506-whale 1.bmp Perhaps you've heard about the wayward humpback whales, a mother and calf, who had become disoriented and began swimming inland towards Sacramento, California. They were traveling down the Sacramento River, causing a lot of grief to the Coast Guard and to marine biologists trying to think of a way to get the pair turned rightways.

Luckily, yesterday the two whales started swimming out to sea again after rescue crews lured them away by playing whale songs in the direction they wanted them to swim. This same ruse was successfully used in 1985 to divert another humpback who had swum around the area for almost a month before being lured back to sea.

An interesting story, and I thought would be a good opportunity to talk a bit about some of the cool properties of whale song.

Listen to a humpback whale song here and an Orca (toothed whale) song here.

Continued under the fold.....

Whale song is the colloquial term for the repetitive sounds that certain types of whales make to communicate with each other. This type of communication evolved due to the limited ability of other sensory abilities (sight, smell, etc)to perform as well in water as on land. On the other hand, sound, and particularly low-frequency sound, has the potential to travel miles in water while preserving the qualities of the information with high fidelity. The speed of sound in water is in fact four times what it in through air. The echos of this transmitted sound can also be utilized by some dolphins and whales to locate objects in space.

The type of sound and method of production of whale song varies between 'toothed' and 'baleen' whales. Toothed whales create high-frequency clicks and squeals (you've probably heard dolphins make these sounds) while baleen whales produce the low-frequency mournful-sounding rumblings. The toothed whales use clicks for echolocation and force air through "phonic lips," which are located in the whale eqivalent of the sinuses, and this sound is focused through a fluid-filled organ in the whales head called a 'melon' or out the blowhole. Why its called a melon, I'm not quite sure...unless it has to do with the shape of the organ which might be described as vaguely melon-shaped.

Baleen whales use a different mechanism to produce sound, and what that is we aren't exactly sure, although they do have a layrnx but no vocal chords. They produce mostly low-frequency sounds, below 5000 Hz (which is towards the lower end of human hearing range) and much of it in the 20-200 Hz range. Songs can last half-an hour or more, and are predominantly produced by males in breeding zones. Humpback whale song has a predictable structure: the base "notes" of the song are very low-frequency bursts of sound lasting several seconds which may be frequency or amplitude modulated.

A collection of four or six units is known as a sub-phrase, lasting perhaps ten seconds (see also phrase (music)). A collection of two sub-phrases is a phrase. A whale will typically repeat the same phrase over and over for two to four minutes. This is known as a theme. A collection of themes is known as a song. The whale will repeat the same song, which last up to 30 or so minutes, over and over again over the course of hours or even days. This "Russian doll" hierarchy of sounds has captured the imagination of scientists.

In addition to the "mating song" there's also a "feeding song"; this is the song that the whale rescue team used to lure the wayward calf and mom back to sea recently. This song is a 5-10 second sound of stable frequency, repeated. Likely this evolved due to the cooperative nature of Humpback whales' feeding patterns (some swim underneath schools of fish and lunge up).

I also wrote a post about the inner ear and cochlea of whales (its huge!), check that out here if you like.

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There sure is alotta hype and attention about these two particular whales, everyone wants to see them return to the sea where theyll be bombarded by low/midrange sonar at the rimpac games and hunted by japanese whaling ships. This Sow and her calf will be lucky to make it back to hawaii next winter. What Kinda damage is done to the inner ear and cochlea of whales from sonor, no one cares about regenerating ear hairs!!! Beter redefine your thesis if you really want to make an impact in the world.
Aloha Big hawaiian

By BigHawaiian (not verified) on 21 May 2007 #permalink

And don't forget the incident in 1984 when two humpback whales were set free from the San Francisco Marina, and were in danger of being attacked by poachers until the U.S.S. Enterprise transported them aboard and travelled far into the future, where whale-song was the only thing that would appease the mysterious deep-space probe that was wreaking havoc on Earth. :P

I didn't know that there were two different generation mechanisms, though I was aware of the melon reception difference. Two entirely different sound systems, curious.

Right now I'm wondering if the mystery of the beautiful baleen songs are something I want to know. Since sounds from herrings turned out to be produced by their gastrointestinal tract (farting; an IG Nobel prize research btw) ...

In addition to the "mating song" there's also a "feeding song"; this is the song that the whale rescue team used to lure the wayward calf and mom back to sea recently.

So it isn't only in males the cravings of the stomach can go before that of romance. :-)

By Torbjörn Larsson, OM (not verified) on 21 May 2007 #permalink

Truth be known, it isn't clear that the whale song coaxing has done much at all. For all we know the quality of the speakers make those fake calls sound absolutely ridiculous to the whales. They completely ignored the sounds for a while, and now for no obvious reason changed their minds and started to leave. For all we know whales sometimes come inland for a while just because they feel like it, always know where they are, and always leave when they need to after a while. The last one did the exact same thing. They probably tell their whale buddies about all these really annoying speakers the humans set up which make obnoxious noises which almost sound like other whales.

By Bram Cohen (not verified) on 21 May 2007 #permalink

Ha, yes probably we're giving the fake whale song a bit too much credit and the real whale brains not enough. The whole incident seemed to upset the people a lot more than the whales at least. :)

As to the generation of the baleen whale song, cetacean biologists think its likely produced in the (equivalent of) the throat/larynx and echoed around the whale's body as opposed to a melon organ. Just speculation though. Herrings communicate by *farts*? LOL!

Good call on the importance of whale song to the universe, Skrud. My favorite part of that movie was when Scotty was "inventing" transparent aluminum and kept saying "Hell--oooo computah....Computah.....Computah?!"

And as to what sonar does to whale ears, its doesn't do a thing to harm the hair cells. Very likely it might disorient them or facilitate crashing into boats or something, but the necessary decibel levels to cause hearing loss in whales underwater is very rarely present. I study mammalian hair cell regeneration, and as whales are mammals they would benefit from my thesis as much as people and guinea pigs. So, no, I don't think I'll reconsider.

This reminded me of a story I read last year, where a whale carcass was found in central Alaska, about 1000 river miles from the ocean.

From the Anchorage Daily News article:
The carcass of a young beluga whale was found Friday by canoeists on the Tanana River seven miles upstream of Nenana and about 40 miles southwest of Fairbanks.
That's nearly 1,000 river miles from the Bering Sea, the closest habitat for belugas.
What the 8-foot-long whale was doing that far inland on a freshwater river, part of a system that drains much of the vast interior of Alaska, remains a mystery. But Link Olson, curator of marine mammals at the museum, said he was confident the animal swam from the ocean. Perpetrating a hoax along a remote section of river with the body of a whale was highly unlikely, he said.
"If you were ever close to a dead marine mammal, even for a few hours, you would know why no one in their right mind would do that," Olson said.
It could have died in the river last fall and frozen. On the other hand, the whale could have entered the river this spring seeking fish heading for the ocean. After dying, it could have begun "cooking from inside out, with all that blubber layer."
A Nenana fisherman, Ed Lord, called Brunner on Thursday and said he spotted the carcass in early May, four days after ice left the river. He was motoring his riverboat upstream, heading to his family's cabin, when he saw birds feeding on something.
"I thought it was a moose," he said.
He speculates that the whale followed salmon upstream last fall, and when the river froze, could not surface for air and died. The carcass was near a section of the river that jammed with ice this spring.
The whale may have set a North American record for swimming inland farthest.

Original Article:

If you want to see where it was found on Google Earth, go to 64�40'2.27"N,

They produce mostly low-frequency sounds, below 5000 Hz (which is towards the lower end of human hearing range) and much of it in the 20-200 Hz range.

I had to read that twice because in music 5000 Hz would be considered a high frequency sound. 5000 Hz is higher than the highest piano key. 10000 Hz is only an octave higher than 5000 hz. 200 Hz would be in the middle frequency range (musically speaking). You're right of course, but it just seemed kind of odd seeing it put the way you put it. Just thought I would share that!

"below 5000 Hz (which is towards the lower end of human hearing range)"

I'm not so sure you're right there. Our hearing ranges from 20 Hz to 20,000 Hz. I wouldn't exactly put it at the lower end.

SB: Yes. What I meant to say was that the majority of the sounds produced are towards the lower end of human hearing (mostly 20-200 Hz) but that all the baleen whale noises are below 5000 Hz.

Note also that the purpose of whale song is unknown. Because it is only heard in the mating grounds, and is only sung by males, one theory is that it is related to mating or mate selection. However one intriguing recent theories relates the technical acoustic properties of the song, and relates it to its possible function as echolocation. Further mysterious is the length and complexity of song, and why all the whales in a region converge upon singing the exact same song.

News -- would you believe "Whale Idol"? Seriously, if the whale song is used to attract female whales, perhaps the most effective song eventually wins out and is picked up by everyone. I seem to remember something about whales from the Indian ocean making their way to the Pacific, and within a few years portions of the Indian whale songs were incorporated. The evolutionary advantage to seeking out some novelty along with the "group think" is an exercise for the reader.

Shelley, as a former paramedic, thanks for your research! Dumb question: why aren't parrot hair cells traumatized by their screams?

SB: Birds naturally regenerate their hair cells! (lucky!) :)

Herrings communicate by *farts*? LOL!

Yes, well, in reality it is funnier still.

The reason most Swedes knows this is because the research were supposedly initiated after the swedish "UFO" sightings and soundings of Russian submarines in the Baltic Sea after the one of them stranded near a Swedish marine base by mistake.

Turns out the listening posts were not conversant with the herrings. :-)

The 2004 Ig Nobel Prize Winners
Ben Wilson of the University of British Columbia, Lawrence Dill of Simon Fraser University [Canada], Robert Batty of the Scottish Association for Marine Science, Magnus Whalberg of the University of Aarhus [Denmark], and Hakan Westerberg of Sweden's National Board of Fisheries, for showing that herrings apparently communicate by farting.
REFERENCE: "Sounds Produced by Herring (Clupea harengus) Bubble Release," Magnus Wahlberg and H�kan Westerberg, Aquatic Living Resources, vol. 16, 2003, pp. 271-5.
REFERENCE: "Pacific and Atlantic Herring Produce Burst Pulse Sounds," Ben Wilson, Robert S. Batty and Lawrence M. Dill, Biology Letters, vol. 271, 2003, pp. S95-S97.
WHO ATTENDED THE IG NOBEL CEREMONY: Lawrence Dill, Robert Batty, Magnus Whalberg, Hakan Westerberg.

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By Torbj�rn Lar… (not verified) on 23 May 2007 #permalink