Science on the SPOT: Sound Waves – Listening to Orcas
Topics: Biology, Environment, Video
Science Education Collections: HS Physics
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Orcas Educator Guide ( pdf ) A resource for using QUEST video and blogs in the classroom; created by PBS partner station KCTS 9
LIME KILN STATE PARK, SAN JUAN ISLAND – It is hard to describe what it’s like when you see a killer whale up close. “Awe” and “inspiring” are the two words that come to most people’s minds. If you ever want to have that awe-inspiring experience, then Lime Kiln State Park on San Juan Island, Washington is the place to go.
“This is the foremost whale watching park in the world,” says retired professor Val Veirs. “There’s no place else in the world you can go with a higher probability of seeing a whale.”
Veirs, who taught physics at Colorado College for more than 30 years, visited the San Juan Islands on vacation with his wife Leslie and never left. Unable to spend his retirement idly, Veirs turned his attention from particle waves to sound waves, and took up the hobby of recording underwater marine life. That’s when he heard his first killer whale.
“Somebody who was making recordings sent me a tape, it was back in the days of cassette tapes, and he played this tape and I said ‘Wow, that’s not what I’ve been hearing on my hydrophone, I’ve been hearing ferry boats and crabs, but I haven’t heard these marvelous sounds that these animals make.”
Now Veirs puts almost all of his efforts into tracking orcas. “Listening to the underwater sounds of the sea is an effort to try to understand the acoustic environment of the killer whales that very commonly visit this island,” he says.
Veirs recordings confirm what many scientists have theorized about orcas. Different groups of killer whales – known as pods – have different sounds. “There are about 85 animals in three pods, labeled J, K, and L,” says Veirs, “and each of those pods seems to have a signature or contact call. By listening to these a lot, you kind of develop a sense of the vocabulary.”
What that vocabulary is telling Veirs is that the Southern Resident Killer Whales of Puget Sound are in trouble – threatened by a lack of food, pollution, and underwater noise harassment. It is this third factor that interests Veirs, mostly because he hears it firsthand.
“If we were listening to the underwater sounds we might hear the waves lapping on the shore, but that would soon be interrupted by the high speed whine of a speed boat. And then echoing and rumbling we would hear a container ship coming in from Asia coming around the corner of Vancouver Island.”
Sound travels through the air at about 700 miles-per-hour. Underwater, it travels even faster – closer to 3,500 miles-per-hour. Veirs says, if you want to know what it’s like to be an orca, imagine living under the flight path of an airport and next to a train station at the same time. Veirs says his research shows that the whales are compensating for all that noise. “We’ve had three or four experiments which have documented the fact that the whales speak more loudly when the background noises are higher.”
Underwater noise isn’t just a nuisance for orcas. It’s critical for their survival, since killer whales rely on echolocation to find their food. Orcas emit a high-pitched click, which, like sonar, bounces off their prey and tells them exactly where a tasty salmon might be swimming nearby. “If it’s harder for them to hear their echoes then they won’t be able to detect,” say Veirs. “The fish that used to be 100 meters away now maybe it can only be 20 meters away.”
One thing that scientists would love to know is whether the orcas’ chirps and whistles are just general communication, or whether they are a more formal language. In other words, are the orcas actually speaking to each other? Val Veirs thinks he has the answer. In a recording made a few years ago, Veirs documented a mother orca “talking” to her calf, which was approaching Veirs’ research boat.
Analyzing the recording afterwards, Veirs was able to triangulate the calls and recreate the communication. “The reconstruction on the computer looks like, [the calf saying] ‘I’m going over there… I’m going over there.’ [Then the mother says] ‘Don’t go over there, don’t go over there,’ a little louder. And in that intense back and forth, the young whale turns away from the boat.”
Whether Veirs has documented the first evidence of an orca “conversation” or not, he is committed to continuing to study these iconic animals. “Our goals for this are multiple. One is kind of public education. Another is trying to move toward a deeper understanding of how the underwater noise may affect the behavior of the orcas.”
“Once we understand that, and we understand that those noises may make it harder for the whales to forage, to navigate, to communicate, then we have a chance to take some societal steps to give them a little better chance.”
Listen to various sounds the Orcas encounter around San Juan Island in this map below.
Produced by Kevin Bang, KCTS. View Listening to Orcas – KCTS 9 Quest in a larger map
Additional Linkshydrophones, killer whales, Lime Kiln State Park, noise pollution, orcas, pods, salmon, Val Veirs