Cosmo
Hey, Dr. Universe.
Dr. Universe
Hey, Cosmo.
Cosmo
Why do sharks live in salt water?
Dr. Universe
I don't know. Why?
Cosmo
Because pepper water makes them sneeze!
Dr. Universe
Hey, friends, I'm Dr. Universe.
Cosmo
And I'm Cosmo.
Dr. Universe
And if you're anything like us, you've got lots of big questions about our world. Today's question comes from Prince in Georgia, who asks: What happens if you get eaten by a shark?
Cosmo
Yikes, that sounds scary. Have you ever been nervous about sharks, Dr. Universe?
Dr. Universe
Oh, definitely. When I was a kitten, I saw a movie about shark attacks, and it made me nervous to go into the water. But I talked with my friend, Dr. Nora Hickey, a fish veterinarian at Washington State University. And guess what she told me: sharks don't actually eat people or cats.
Cosmo
Wait, what? They don't?
Dr. Universe
Nope. Many sharks can't even bite. They have mouths designed to sift sand or slurp up plankton. And the sharks that can bite usually go for prey with a thick fat layer like seals and sea lions. Muscly animals like birds, cats, and people don't taste so good to sharks.
Cosmo
So, if one did bite me…
Dr. Universe
It'd probably be like, “No, thank you” and spit you right out.
Cosmo
Okay, so if humans are a bad snack, why do sharks sometimes attack them?
Dr. Universe
Most of the time it's a mistake. Or the shark is just defending itself. Sharks have incredible senses. They can smell tiny traces in the water from very far away. They can hear for miles. And they can even detect electricity in the water.
Cosmo
Detect electricity? How?
Dr. Universe
Have you ever seen a picture of a shark's snout? It has itty bitty holes all over it. Those are pores called ampullae of Lorenzini. They're filled with a snot-like jelly that helps sharks sense electrical signals from living things like mollusks hiding under the sand.
Cosmo
Whoa. So, if I'm splashing around, a shark might think I'm dinner?
Dr. Universe
Exactly. It might take a nibble to check.
Cosmo
Yikes.
Dr. Universe
The shark would probably chomp down and then shake its head from side to side. It does that to get a good bite because sharks can't chew up and down like we do.
Some sharks roll back their eyes when they bite or slide a protective membrane over them. That protects their eyes if the prey fights back.
And you can expect some of its teeth to pop out when it bites you. Shark lose teeth all the time. They have rows and rows of backup teeth ready to go. Dr. Hickey told me the ocean floor is covered in shark teeth.
Cosmo
That's cool. And also kind of gross.
Dr. Universe
Pretty much. But here's the thing: once the shark realizes you're a human or a cat, it'll usually swim away. Still, if you did get swallowed, you'd take a very weird ride.
Cosmo
Oh, boy.
Dr. Universe
Sharks and sturgeons have a spiral valve intestine. It's like a twisty water slide. All those twists and turns help them digest food without a super long gut.
Cosmo
So, I'd be sliding through a shark's intestines?
Dr. Universe
Yeah, you or some piece of you. But the truth is that humans are much more dangerous to sharks. People hunt them and accidentally catch them in nets. That's super bad because many sharks need to swim in order to breathe. If they get stuck, they can't move water over their gills.
Cosmo
Plus, humans drive loud boats through their homes. And sometimes try to touch sharks in the wild, which is a terrible idea—even if the shark seems gentle.
Dr. Universe
Exactly. Sharks are powerful and fascinating and a little misunderstood. That's all for this episode, friends.
Cosmo
Big thanks to Dr. Nora Hickey for helping us out today and to Prince for the fantastic question.
Dr. Universe
As always, if you've got a science question for me, you can submit it at askdruniverse.wsu.edu. That's A S K D R U N I V E R SE dot W S U dot E D U.
Who knows where your questions will take us next.
