Finding Nemo is my favorite movie of all time and I vividly remember when it came out. I went to see it in the theater with my family and when the scene came when Dory can’t seem to remember P. Sherman 42 Wallaby Way Sydney, a child sitting behind me yelled at the screen in tears, “It’s okay Dory, I would forget too!”
Dory is quite the fish. Not only does she help Marlin find Nemo but she also speaks whale! And although I can’t name it as my favorite scene in the movie I do laugh every single time I watch the scene where Dory asks the whale for directions. She moves through a few different species, claims that one of her dialects sounds a little orca and also suggests that maybe she try speaking humpback. Dory proceeds to make what seemed to me at the time, ridiculous sounds.
I used to think the dolphins held the title for most ridiculous sounds. I’ve heard things that sound like almost any farm animal or instrument you can think of, cows, ducks, dogs, banjos, you name it. But in the last week the humpback whales have done their fair share of surprising me too. The thing that has surprised me most recently is the range of frequencies humpbacks use. Baleen whales, the Mysticetes, generally use low frequencies, bigger the body, the lower the frequency and the smaller animals, like the spinner dolphins, higher frequencies. If you think about the type of sound a humpback would make, think of all the whale songs you’ve heard, are they high in frequency like a bird singing or are they low in frequency? I would say low too. But check out the harmonics on this humpback!
Again this is a spectrogram. Along the left hand side of the picture (the y axis) is frequency in cycles per second. We sample at 80,000 cycles per second but we can only accurately represent up to half of that, 40,000 cycles per second due to something called the Nyquist Theorem. The brightest line in the picture is called the fundamental frequency it is where most of the energy of the signal lies. The rest of the lines are the harmonics and fall at multiples of the fundamental. When we listen to the sound of the humpback we hear one sound, each of the harmonics comes together with the fundamental frequency as one sound. But these harmonics go ABOVE 20 kHz! The spinner dolphin whistles I listen to are generally between 2 and 22 kHz! And the craziest thing is that I can’t hear at least the top three harmonics of this humpback sound. When my ear processes that sound I can’t make out the top three lines. I have lost some of my high frequency hearing, too many concerts… If you’re interested in finding out what harmonics you can’t hear try this hearing test. The best hearing human can hear from 20 Hz to 20 kHz. My hearing cuts out at around 15 kHz.
So sure the whales do use a lot of low frequency sound but that have quite an impressive ability to produce very high frequency harmonics, higher than I can hear! I guess I’m not quite as surprised as I used to be when I heard Dory speak whale. These whales do make some crazy sounds.
Take a listen to this file here!