Hi, everybody!
I am a comparative anatomist.
A comparative anatomist is someone who studies the structure of the body
of lots of different animals.
And my favorite animals are whales.
I like to study whales because they're so interesting.
They've adapted to a unique environment of living in the water.
And what I'm going to tell you about is how whales make sounds
by basically farting with their face.
You know that they do this farting thing with their blowhole;
they blow out air like that,
but they also use air in lots of other ways.
They use it for sound production, which is what I'll focus on,
but I also study other things they do with air,
like keep it out of their bloodstream so they don't get bubbles,
which is what happens to human scuba divers
when they get decompression sickness.
But I'd like to start with the story
of how these animals make these farting noises,
and that story begins with understanding how hard it is to look at whales,
because they live underwater and they're really big,
so they're hard animals to study.
And in this picture -- you see that animal in the middle?
That's a baby whale and it's already the size of a bus!
When you look at whales, start with the top of their head
because their nose is on the top of their head,
kind of like a built-in snorkel.
They breathe through that because they're mammals
and mammals breathe air.
Their nose can be opened and closed,
as if you were to pinch it like this.
You can see it's open in the bottom frame, where the red arrows are.
But not all whales have two nostrils.
Whales include the groups of dolphins and porpoises,
and dolphins and porpoises, the small whales,
have only one nostril on the top of their head,
and they open and close that nostril
by taking what is essentially an upper lip, like this,
and turning it back over their nose, like this.
That's how they open and close their nose.
So when they make sounds,
what they're basically doing is a raspberry,
(Makes raspberry sound) which is kind of like a fart, right?
Or up in New York, we call it a Bronx cheer.
And the way they do that
is by taking that big, fatty structure of a big fat lip,
which, as you can see here in this picture,
which is a cut through the middle of a dolphin's head,
that big fat lip is that big yellow portion there,
and they roll it back and forth over the top of their nose
so that they vibrate it,
kind of like when you let the air out of a balloon
and it makes that weird vibration sound.
So this is what it sounds like when they make their noise:
(Vibration noise)
Hear it? He'll do it again when he faces the camera.
(Vibration noise)
Sounds like it's farting underwater.
What that dolphin is actually doing, though, is echolocation,
which is making these series of pulses,
and it uses it like a bat uses sonar.
Well, a bat uses radar, but when it's underwater it's sonar,
so this animal is using sonar to see its world in sound.
Trying to understand how this works, you have to look at it
as if you were looking at the amplifier speakers of a sound system.
The small-toothed whales are basically the "tweeters,"
and the sound is coming from that little nose
that's moving back and forth and coming out of their forehead.
But the big whales are kind of like the "woofers,"
the big speakers that you have in an amplifier system.
And what's happening is their sound is coming out of the throat.
So if you tried to make sound like a whale --
make a sound right now, and go, "ahhhhhh."
OK, now put your hand on your throat, on your Adam's apple.
You feel that vibration right there?
That is lost energy for you,
because that's not how you communicate to everybody.
You do it out of the mouth.
But if you open your mouth underwater, no one will hear you.
You have to be able to take this energy and amplify it through the water.
That's what whales do.
And when you hear their sound --
(Squeaking sound)
it's kind of like when you squeak the air out of a balloon.
So they get a lot of squeaky noises,
but they also have this sound:
(Vibrating sound)
It sounds like it's farting, doesn't it?
It's like it's got this giant whoopee cushion in its throat.
So, how do you know that's what a whale is doing?
Well, we study whales that come to us from strandings.
These are animals that die on the beach.
Small whales like dolphins and porpoises are easy;
we can take them to the lab.
But the big whales -- we've got to bring the lab to the whale.
And this is what that looks like.
I'm the one in the middle with the red hat.
I'm not a very tall person,
so you can see how big this whale was compared to me.
The whale is 65 feet long.
And my scalpel is this little tool on the side here.
It basically looks like a hockey stick with a blade on the end of it.
And doing a dissection of a whale is a very difficult process.
You literally have to get into your work.
It's kind of like a giant bloody construction zone.
You're wearing a hard hat,
you're working with heavy machinery.
In this case, by the way,
that's just the voice box of a blue whale.
Just the voice box.
I'm only five feet tall -- you can see it's like 12 feet long.
How do we know what's going on?
Well, we look at the voice box, or larynx,
and we see -- this is from a baby whale so it's much smaller.
You see this little u-shaped thing I've outlined in blue.
That's the part that's vibrating.
It's kind of like our vocal folds.
When I put my hand in there, where that blue sleeve is,
you can see there's a sack underneath it.
That's the whoopee cushion.
That's the air bubble or the balloon.
So what these animals are doing --
and you can see, there's this big black balloon in the throat,
where the digestive tract, which is in blue,
meets the breathing tract, which is in light blue,
and right in the middle is that black sack.
These animals are using that sack to make these sounds.
And so they vibrate that and send it out.
Small-toothed whales also have air sacks; they're all over their heads,
so it's like they're airheads.
They use this to capture as much air as they can
to take down with them when they're diving,
because when you dive, pressures increase,
and that decreases the volume of air you have available.
But more importantly,
having that sack allows them to recycle the air that they're using,
because air is a precious commodity.
You don't want to have to go back up to the surface to get more.
So when you make a sound underwater, if you're a whale --
let's hear you start making a sound, go "ahhhh."
But whales keep their mouths closed, so go "ahhhmm."
(Audience makes noise)
You're all humming, right?
But whales keep their nose closed and go, "mmmm."
(Makes noise)
What happened?
You can't make the sound anymore once you close your nose
because you've pressurized the system.
Whales, by having air sacks, keep themselves from pressurizing the system,
which means the air continues to flow,
and so if you had a bag on the end of your nose,
you'd be able to make air continue to flow.
So I hope you've enjoyed that.
That's what a comparative anatomist does for a living.
We study the structure of these animals.
We try to mimic it; we apply it back to the human situation,
maybe making new technologies for protective devices
or maybe even making new treatments for medicines
for people's diseases who mimic these weird environments.
So I hope you enjoyed that. Thank you.
(Applause)