Thursday, March 15, 2007
(Photo: Blue Whale.
The language of animals mystifies us. There could be as many as 100 million species in the world. And we don’t know what most of them are saying to each other. But researchers at the Scripps Institution of Oceanography at UCSD have insight into one species. They’re studying the sounds of the largest creature in the animal kingdom. KPBS Radio’s Andrew Phelps has the story.
Not just the largest creature on Earth – but the largest creature ever to have lived on Earth. Larger than the dinosaurs. This is the blue whale.
Dr. Erin Oleson is a Scripps researcher who wants to understand what these sounds mean. She went around the world with waterproof microphones and stuck them on to whales with suction cups. Then she gathered a year of recordings.
Oleson: Going into the study, we knew that the blue whales made two types of sounds. One of those being a song, which is this long, continuous sequence of sounds.
This is a local whale you're hearing – right off the coast of Southern California.
Oleson: So it turns out the song is produced only by males. What this means is we can use this call type to monitor perhaps reproductive activity or at least animals that are motivated and thinking about reproduction.
And as for the second sound…
Oleson: Kind of like individual chirps that you'd hear from a bird, or something. It turns out these sounds come from both males and females. And it also turns out that they're making these sounds when they take short breaks from feeding.
The sound recorders also capture movement. So Oleson can “see” if the whale is diving for food. That’s how she associates behaviors with the sounds. If a popular boating area ends up being a mating area, there might be a way to have the boats moved elsewhere. Blue whales are endangered. There are just 10,000 left in the world.
One of Oleson’s colleagues took her study a step further, by comparing the sounds of different whales. It turns out there are dialects of whale language. The whales have accents.
To help explain, here’s my friend Monica.
Medina : I’m Monica Medina.
People can figure out where Monica is from within moments of meeting her.
Medina : They’ll say to me, they know. “Are you from New York?” And I just kind of laugh. Because I’m shocked that after all these years, they can still hear it.
We humans can hear an accent and identify where in the world it comes from. Now, scientists can do the same thing with blue whales. Researchers identified nine distinct song types. Dr. Oleson says that means nine geographically distinct populations.
Oleson: It's kind of like, you know, the population of the U.S. and then over here is Thailand. You know, they're the same species, and they could interbreed if they came into contact with each other. But they're more or less, kind of, isolated to themselves. And this song probably helps tell them who they are.
This whale is from Sri Lanka.
This one’s from West Australia.
There is plenty of room for further study. For example, Oleson noticed the whales make certain sounds only at night. She wonders if this is some way whales mark time, just like we do.
The research appears in the January issue of the Marine Ecology Progress Series.
For KPBS, I’m Andrew Phelps.