Do insects see the world in slow motion? (2)
Roslyn: Same color as my surroundings possibly.
Molly: Like a camouflage suit.
Roslyn: Yeah, like camouflage but not.
Molly: Whoa. Send us your super-suit ideas by heading to brainson.org/contact
Roslyn: We might use your answer in the show!
Molly: And while you're there, you can send us mystery sounds, drawings, ideas and questions.
Roslyn: Like this one:
Molly: Rebekah from Pocoima, California wrote to us asking: Why are we lighter in the pool? My little sister can carry me and I can carry her. Why is it so easy for us to do that?
Roslyn: Such a good question!
Molly: We're going to answer that question during our Moment of Um at the end of the show.
Roslyn: And if you stay tuned to the very end of the show you can hear a clip of Smash Boom Best.
Molly: Each episode pits two cool things against each other and our debaters use jokes, stories and facts to argue for their side -- in hopes of persuading our kid judges that they are truly the smash boom best.
Roslyn: At the end of this episode you'll hear a preview of -- ooh, this is a good one -- flying vs invisibility.
Molly: Stay tuned!
(music)
Roslyn: You're listening to Brains On from American Public Media. I'm Roslyn.
Molly: And I'm Molly. Okay, before we get back to eyes, we need to go back to our ears first. Let's hear the mystery sound one more time.
(plays sound)
Molly: Before you said a seal, maybe a seagull. Do you have any new guesses?
Roslyn: I think I'll stay where I was, I guess.
Molly: Some kind of animal.
Roslyn: Some kind of animal that's fairly obnoxious.
Molly: (laughs) Well, here is the answer.
Tiffany: So the sound you just heard is the call of a bald eagle. My name is Tiffany Ploehn and I'm the avian care manager of the National Eagle Center.
Molly: Did you know that? Have you heard an eagle before?
Roslyn: I have actually, at our cabin I hear them all the time.
Molly: It's hard when you hear these sounds out of context, you know. You could hear something super familiar to you and when you hear it out of context it's super hard. But that's really cool you get to hear bald eagles!
Roslyn: Yeah.
Molly: I've never heard a bald eagle before. That's not what I would imagine it sounds like.
Roslyn: They're loud.
Molly: Very loud. Are they obnoxious like you thought?
Roslyn: Sometimes. It's cool when you hear them though.
(eagle sound)
Molly: The National Eagle Center is in Wabasha, Minnesota, they educate people about these winged wonders. And if you are surprised that that was the sound of a bald eagle - you are not alone. Tiffany says most people think a bald eagle sounds like this:
(HAWK SCREECH)
Molly: But that's not a bald eagle.
Tiffany: When you see eagles in movies and commercials and you see them flying around, you always hear that really loud majestic caw sound, and that's actually a red tailed hawk sound and they dub over an eagle sound with it.
Molly: Cool trivia, right? But back to eagles -- they have some of the sharpest vision in animal-land. In part because their eyes are super special.
[MUSIC]
Tiffany: Eagle eyes are pretty unique in that they have actually two focal points in their eyes - or fovea. So they have kind of binocular vision like we do, so they can see straight forward. But then they have monocular vision, that goes off about 45 degrees in each eye.
Molly: So imagine being able to see very clearly what's ahead of you. But also, what's lurking at the side of your vision -- you can see that clearly too.
Tiffany: And by going back and forth between them they can get this really distinct 3D vision. And so that's how they have such fantastic depth perception.
(EAGLE CALL)
Molly: This helps them hunt tiny critters like rabbits and rats. Tiffany says eagles also have extremely large eyes compared to their head size and they can see ultraviolet light. Overall, their vision is 4 to 5 times better than ours.
Tiffany: For instance, we have some fun comparisons -- like, an eagle, if they were sitting on top of a ten story building, could look down and actually see a carpenter ant walking along the sidewalk. Or they can see a rabbit - if it was running, if it was about 24 inches long, they could see that rabbit running along a bluff about three miles away.
Molly: Not bad eagles. Not bad.
(music)
Molly: Now let's answer the question that inspired this whole episode.
Roslyn: Is it true that small bugs and insects see humans moving slower than they are? Or do we see ourselves moving faster than we think?
Molly: To find the answer, Roslyn and I visited a lab at the University of Minnesota.
Paloma: My name is Paloma Gonzalez Bellido. I am an assistant professor at the ecology, evolution and behavior department at the University of Minnesota and I study how insects see the world and how they catch their prey.
Roslyn: Paloma and her team invited us to their lab and answered many of our questions about how insects see the world.
Molly: Researchers Kate Feller and Sergio Rossoni started by showing us where they raise the insects they study.
(in the lab) Molly: Wow, it's warm in here…
Kate: Yeah! So this is the room where we rear all the insects. You'll notice it's pretty warm in here and it's very high humidity. And that's essentially to keep them happy because otherwise if it's too dry in the winter we really struggled with getting them to not dehydrate.
Molly: They raise dragonflies and killer flies.
Kate: We're really interested in the fact that they hunt and kill stuff. And they do it while they're flying.
Molly: And so in studying the way these insect catch other insects to eat -- they need to study the way their brains work -- particularly the way they see.
Paloma: They definitely see much faster than we do. Basically they have photoreceptors that work really, really quickly. And photoreceptors are the cells in your eyes that transmit light into electrical energy. Those are the ones that make us see. And they have a very nice and tricky difference to the way that our eyes work and that's why they can see so fast.
Sergio: You might have seen films of giants that move really slowly compared to us. And that's because any animal that's bigger is gonna require a lot more muscle force, that's going to require a lot more time to be able to develop. So the smaller you are the faster you can move. So if you're going to see very slowly and move very fast, that's not going to be very efficient so vision is going to match up and try to be as fast as your movements are. We've got slow vision compared to most other animals because we don't require that fast vision because we can't move that fast anyway so that would be a waste of energy.
Kate: Yeah, your question actually sparked a very interesting philosophical debate. (laughter) It's a bit of a misrepresentation to say -- at least I think -- to say that insects have slow motion vision or that they see the world in slow motion because I can't ask them how they perceive time and space and we can never ask them because we can't talk to them directly. However, they do have high speed vision kind of like a high speed camera. So the slow motion camera on your phone is actually a higher speed camera than your regular camera. It's capturing frames at a faster rate that our visual system is able to.
Molly: How do you study their brains? Because you can't put electrodes on them -- or can you?
Kate: You can. You put little electrodes on them and you measure the electricity.
Sergio: Very patiently and with a microscope.
Kate: Very delicate and very patient.
Molly: How do you get them to stay still?
Kate: The cold actually is a very good anesthesia.
Roslyn: And how do these discoveries help modern day technology would you say?
Kate: I mean it's like a little flying high speed camera that's able to grab stuff out of the air. I can think of a lot of applications for that. We're the modern day explorers that figure out what's going on in the natural world and then people who do more applied work building stuff and inventing things can take the principles we've figured out and then implement them in their own designs.
[THEME music]
Roslyn: There's a whole range of light -- it's called the electromagnetic spectrum.
Molly: Humans can only see a portion of it. We call that part “visible light.”
Roslyn: But some animals can see more kinds of light that we can - like infrared light or ultraviolet.
Molly: Eagles have two focal points in their eyes which give them extra powerful depth of vision.
Roslyn: And insects do indeed see things differently than we do.
Hawkmoth: And HAWKMOTH can see better in the dark because HAWKMOTH can slow down HAWKOTH's brain. Yay HAWKMOTH!
Molly: That's it for this episode of Brains On.
Roslyn: Brains On is produced by Marc Sanchez, Sanden Totten and Molly Bloom.
Molly: Our fellow Menaka Wilhelm sees all. We had production help from Kristina Lopez and Jackie Kim. We had engineering help from Veronica Rodriguez. Special thanks to Becky Hartley, Helen Bond Plylar, The Dino Birds, Glen Jeffrey, Ricky Patel, Brenna Everson, Peter Ecklund, Misha Euceph, James Kim, and Arwen Nicks.
Roslyn: Brains On is a non profit public media podcast. Your support helps us keep making new episodes.
Molly: Head to brains on dot org slash donate to give and while you're there you can see our cool thank you gifts.
Roslyn: Now before we go it's time for our Moment of Um….
Chen: Hi, hello! My name is Xie Chen. I am an associate professor at Cal Tech here in the Physics Department. And I study theoretical physics.
Molly: Who better to answer Rebekah's question about why it's so much easier to pick people up when they're in a pool.
Chen: That's a great question! And the answer to that is well water is helping you. Water is doing the job of holding things up. So imagine you have a rubber duck in your hand and if you're standing on the ground, you let go of the rubber duck, the rubber duck will fall to the ground. Right? But if you're standing in the pool and you let go of the rubber duck, the rubber duck would float on the surface of the water. And even if you pull the rubber duck beneath the water surface it will pop up to the surface so that's because flotation. Because water is holding things up. Of course we are much heavier than the rubber duck so when we are in the water we do not automatically just float on the surface but water is still doing some of the work to hold us up. And actually if you go somewhere in the Medtierranean there is a place called the Dead Sea. And the Dead Sea it contains so much salt that it's doing a much better job at holding things up so when people swim in the Dead Sea they actually just float on the surface. There's no problem of sinking beneath the water.
Molly: Water may help keep us afloat, but these names are all I need to keep my spirits up! This is the newest group of listeners to join the Brains Honor Roll. These are the people who sent us Mystery Sounds, pictures, drawings and questions to help fuel the show.
HONOR ROLL
Roslyn: We'll be back soon with more answers to your questions.
Molly: Thanks for listening!
