Baleen Whale respiratory anatomy allows for sound production
Guests on Wednesday’s Wake up with the Whales Cruise spent most of the trip with a lone (and possibly lonely) whale. This big Humpback was in a slow, surfacing and sounding pattern, and we got to see his very white flukes on a number of occasions. When we deployed our hydrophone, we only heard one Humpback voice too (though it wasn’t from the whale we were watching).
After we returned from this cruise we reboarded and headed out on our Snorkel Adventure Cruise. Towards the end of this trip, we encountered a Mom/Calf duo — our onboard naturalist Dave was pretty sure it was the same pair we spent time with on Monday. Anyway, baby was pretty squirmy — we got to see him do a couple of head lunges, and Mom surfaced right next to him during one of those little lunges.
Mahalo,
Claire
Ocean Sports Whale Fact of the Day: Over the past few months, we’ve mentioned frequently that we’ve gotten the opportunity to listen to Humpback voices but we haven’t touched at all on how Humpbacks produce those sounds. When you’re singing, the way you make sounds is by passing air over your vocal cords. If you could do that underwater, bubbles would float to the surface. When Humpbacks sing, there aren’t any bubbles coming up, so we know they’re doing something completely different.
Though Humpbacks don’t have actual vocal cords, they do have a u-shaped fold situated between their lungs and some inflatable organs that we call “laryngeal sacs” (see the graphic above). Though it’s basically impossible to observe the internal organs of a living singing whale, researchers are pretty sure that whales create sounds by contracting their throat and chest muscles, which forces air from their lungs across the u fold, which causes it to vibrate. The vibrations resonate in the laryngeal sacs, creating those beautiful, very loud and haunting sounds — after which the air passes back over the u folds (creating more vibrations) on the way back to the whales’ lungs. Since no air is actually exhaled, no bubbles float to the surface.