A Marine Ecologist On Swimming With Sharks And What 'Jaws' Got Wrong Neil Hammerschlag has looked inside the mouth of a wild tiger shark and lived to tell the tale. He says that sharks pose only a very small risk to people: "Humans are not on the shark's menu."
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A Marine Ecologist On Swimming With Sharks And What 'Jaws' Got Wrong

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A Marine Ecologist On Swimming With Sharks And What 'Jaws' Got Wrong

A Marine Ecologist On Swimming With Sharks And What 'Jaws' Got Wrong

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TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. It's summertime, when a lot of us head to the beach and try not to think about the man-eating sharks we've seen in movies like "Jaws." Remember Hooper, the shark expert played by a young Richard Dreyfuss?

(SOUNDBITE OF FILM, "JAWS")

RICHARD DREYFUSS: (As Matt Hooper) What we are dealing with here is a perfect engine, an eating machine. It's really a miracle of evolution. All this machine does is swim and eat and make little sharks. And that's all.

GROSS: Our guest today is a real-life Hooper of sorts. Dr. Neil Hammerschlag is a marine ecologist at the University of Miami, where he directs its Shark Research and Conservation Program. He spends a lot of time on and in the water. He's caught and tagged more than a thousand sharks for research and has studied and filmed some of the largest of the shark species, the great white and tiger sharks. The tags he implants in sharks transmit information about the health and behavior of these predatory animals.

Hammerschlag has some tips on how to stay safe around them, and he'll explain how we're much more of a threat to sharks than they are to us. His work is featured in two of the episodes of The Discovery Channel's recent Shark Week. He spoke with FRESH AIR contributor Dave Davies.

DAVE DAVIES, BYLINE: Well, Dr. Neil Hammerschlag, welcome to FRESH AIR. I'd like to start with an experience - and this is something that you mentioned in a TED talk - of an encounter with a shark about 10 years ago. What happened?

NEIL HAMMERSCHLAG: Yeah. I mean, it was a beautiful late afternoon, early evening in the Bahamas. And I was on a boat - a live-aboard, meaning you kind of live and sleep on the boat. And we were diving throughout the day. We were actually looking for sharks, so we were baiting them in, trying to get close. And we had had limited success. We hadn't seen that many sharks. And so it was getting late. I went into the shower to kind of wash up, and I heard someone yell tiger shark. And I had never seen one before so - you know, I was a bit younger and more excited and I guess green.

And I put on my snorkel gear and grabbed my camera, ran to the back of the boat and pretty much just cannonballed into the water and saw these huge two tiger sharks approaching me, 3-and-a-half-foot-wide heads coming close. One peeled off, but the other one moved right in towards me and came so close that actually, it couldn't even see me from looking dead on because like all fish, they kind of have the eyes on their - side of their head.

So they're - it was so close that it had to rotate around to kind of eyeball me up and down. Then it rotated back and opened its mouth - and I was looking through its mouth down its, you know, gut and seeing its gills from the inside - closed its mouth again. It circled me several times. It swam off only to come back and do that all again. You know, come so close that it had to rotate around to eyeball me, swam circles around me, and kind of moved back off into the dark water because it was evening at that time.

DAVIES: When the shark approached you, were you afraid?

HAMMERSCHLAG: You know, I wasn't afraid, actually. It was such an intense encounter. You know, it was certainly thrilling, but it was more of a sense of kind of awe. It was opening its mouth, but it wasn't in pursuit. It wasn't, like, trying to bite me or anything. It was kind of standing still. And it was probably helping enable the shark to funnel water in its mouth and over its gills, or maybe it was some sort of communication. You know, I know from some of my past research a shark sometimes will kind of show off or show some dominance by opening and closing its mouth.

DAVIES: I know from reading about you that you do a lot of research on tiger sharks near a place called Tiger Beach. It's in the Bahamas, right? You want to just describe it?

HAMMERSCHLAG: Yeah. This is actually where this occurred. It was the first time I had ever been to Tiger Beach. Tiger Beach - although it's called a beach, it's nothing close to a beach. It's a shallow water area on the Little Bahama Bank in the Bahamas. And the reason - a friend of mine who found the area named Jim Abernethy, he nicknamed it Tiger Beach as - in hopes of misleading trophy fisherman who would - might be looking for big tiger sharks to maybe catch and kill them. So it was a way to mislead them. They would - might be going looking for a beach. But in fact, there's no land around. It's just a shallow water area.

And surprisingly, it's averaged around 15 to 20 feet deep. However, you have numerous tiger sharks that are actually longer and bigger than the depth of the water there. You know, numerous animals that are over 15 feet swimming around there, and just a high density of tiger sharks. And what's amazing is usually an area doesn't have a lot of big predators. It takes a lot of food to support a single predator. So - a very large predator. So, you know, one area doesn't usually have a high density of these big, you know, kind of super predators swimming around.

So to find a spot where it was dominated by these predators - and in fact, they happened to be all female. Well, the majority were female. It was really intriguing to me, so it kind of set off a pursuit - this research pursuit to try to figure out why there are so many big tiger sharks in this one shallow area, and why are they mostly female? You know, if it was really great for food, I would've thought we would also be seeing a lot of big male sharks. So that kind of sparked the interest there to make that a strong research priority.

DAVIES: Right. In one of the Discovery Channel episodes of Shark Week, they focus on this place and your research at Tiger Beach and your work with tiger sharks. In one of these scenes in the Discovery Channel, you and some other divers are underwater. And I guess you're cleaning off an acoustic sensor that's on the bottom of the ocean, and this swarm of tiger sharks approach and come really close to you. And it looks pretty scary. Can you describe what was going on?

HAMMERSCHLAG: Yeah, we were - it was - I have a series of underwater acoustic receivers. They're underwater hydrophones. And they're set up as listening stations. And what they're listening for are specific transmitter tags that I actually surgically implant in tiger sharks that send out a high-frequency sound that those listening stations are essentially underwater trying to receive. And so every now and then, we go to clean off and also download that data. So we were underwater, relatively shallow, cleaning off these underwater hydrophones, these receivers. And there were several tiger sharks - large tiger sharks - around.

And they got really curious and inquisitive. There was some bait under the water that - you know, minced fish that were bringing tiger sharks nearby. And I think they just got really curious and started coming in pretty close. And we were having to - I wouldn't say it was aggressive, but it was pretty chaotic. There was just a lot more that were around than we - that was easy to keep, you know, your eye on. And so we were kind of having to push them away a bit and had to kind of get out of the water.

DAVIES: Well, I mean, what you see on the video is - you hear the audio of one of the divers warning you and your fellow diver, who's cleaning off these acoustic sensors - you've got another one coming in on your right. Look, behind you, behind you. And there's a sense of urgency there. And then we see you or the divers turn, and then this massive shark comes up. And you put your hand on its nose and push it away. What's going on there?

HAMMERSCHLAG: Yeah. I mean, these sharks are not afraid of anything. And they will come right in close. I mean, these things are - these individuals are built like tanks. I mean, they're 10-plus feet. You know, some of them were easily over 14, 15 feet. They've got this impressive weaponeering in terms of teeth. And they just don't have this kind of self-awareness of being afraid or - you know, they're very curious and inquisitive. And they'll come right in.

And sometimes they'll bite you as exploration. They have a variety of senses, including touch. And they don't have, you know, finger tips like we do to feel things around. Often they use their teeth to feel things. And if they're coming in to give you even an exploratory bite, that's game over in the case of a tiger shark. So we have to be on our - totally aware and making sure that doesn't happen. And when you have five, six, seven tiger sharks swimming around - not to mention probably 10 other smaller species that are less of a concern - it's a lot to keep track of down there. And in one case, you know, these tiger sharks coming up behind you - you've just got to keep your head on a swivel and make sure that they don't actually end up getting too close because the thing is that when they get close, if you're keeping eye contact with them and kind of putting your camera between you and them, they often will turn away. They don't come in.

But if you have your back turned to them, often they'll come in to check you out with an exploratory bite in some cases. And you don't want that to happen. So you - it - there is absolutely a sense of urgency if there's one behind you that you don't see.

DAVIES: And what would an exploratory bite do? I mean, like, kittens will, like, gnaw at you. This - we're not talking about that.

HAMMERSCHLAG: Well, it might not necessarily be aggressive. But the fact - when you have, you know, a couple thousand pounds of animal behind a bite on a head that's several - 4 feet wide, with a mouth that's got these teeth that are serrated, you know, razor sharp and powerful, even - as gentle as they want - would want to be in kind of biting you, it would - in terms of a tiger shark it would be devastating.

Tiger sharks are pretty famous for being able to eat turtles. They're among one of the few species of sharks that because of their dentition and their size and the fact that their teeth are separated, they can cut through turtle bone, turtle shell. You know, they eat whales. They have the power and the tools to pretty much get through anything. So, you know, some wetsuit and skin is not going to be an issue if they end up trying to bite you.

DAVIES: And so when one of these would come too close and you would put your hand on the shark's nose and push it away - you know, if we were out in the wild and a wild animal came to us, I think we would think of pushing them as something that would provoke them to attack. Is that not the case with sharks?

HAMMERSCHLAG: Sharks are ambush predators. So if you happen to see a shark there's a good chance that it's already seen you for a little while. And so in most cases, they are going to not come very close. Most sharks don't like to come away. In most instances, in order to have - get sharks close up, you have to bait them or kind of attract them in with minced fish. If that's the case, they're interested in finding that fish and eating that fish. So you just don't want to get in the way of it.

And, you know, I don't think most people are going to find a situation where they have to push away a shark. But if you do find yourself in a situation where - that you don't feel comfortable with a shark, the best thing to do is not run away or swim away. You know, that's what their food does. Their food runs away from them.

The best thing to do is actually just approach them, maintain eye contact. And I wouldn't try to touch them or push them unless they came, you know, within - so close that that's what they were going to do to you. If they came to open their mouth that might be a situation where you - it would probably be good to push them away. But probably the most important thing is just to maintain very strong eye contact with them and kind of follow them around. And usually they're going to find that uncomfortable.

DAVIES: So if you are swimming and you become aware of a shark - I mean, you can't maintain eye contact with a shark probably out of the water - what do you do?

HAMMERSCHLAG: I would just move slowly, swimming kind of backwards so you're keeping the front of you towards the shark and, you know, kind of backing up slowly out of the water.

DAVIES: OK, (laughter) I'll try and remember to do that.

HAMMERSCHLAG: You know, that's what it seems like...

DAVIES: (Laughter).

HAMMERSCHLAG: ...But people aren't going to really find themselves in that situation. You know, most sharks don't like people. The truth of the matter is that, you know, I spend a lot of time and energy trying to get sharks close to me either to - when I'm diving for fun to see them or when I'm doing research and trying to get them close for - to capture them or to study them. It's actually really difficult. In most cases, we have to bait them in. We have to go to the places we think they're going to be. We have to bait them in with minced fish to kind of attract them.

And it's actually quite challenging to get them to come close to people. And it sometimes - it doesn't take very much to deter them. And it often is just saying hey, I see you and keeping eye contact because they're quite wary of that. A lot of the predatory sharks, including tiger sharks, are ambush predators. And when they know they're being watched they feel a bit uncomfortable and they're less likely to come close to you.

DAVIES: Neil Hammerschlag is a marine ecologist and shark researcher at the University of Miami. We'll continue our conversation in just a moment. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

DAVIES: This is FRESH AIR. And we're speaking with Neil Hammerschlag. He is a marine ecologist and shark researcher at the University of Miami. You've spent all this time in this area in the Bahamas where, as you've noted, there's a large concentration of tiger sharks, particularly females. Have you figured out why they might be there?

HAMMERSCHLAG: I actually thought it would be linked to reproduction. So my colleague and I, James Sulikowski from the University of New England, we went out there with a high-definition ultrasound. And when we were capturing the sharks, we were running these ultrasounds on the sharks, in the field, to see if they were pregnant or not. And what we found is that a high proportion of the females are actually pregnant and mature.

And what we think is that this Tiger Beach area serves as a gestation ground for some of these large pregnant tiger sharks. They're cold-blooded, and so they depend on the water temperature for their metabolism. And, in fact, warmer water helps speed up their gestation. These tiger sharks have gestation periods, meaning they're pregnant for over a year. And warmer water is going to actually help speed up that gestation. And their offspring will actually grow bigger, which is better. And so we think they're using the shallow water, warm, stable areas as a gestation ground to help with accelerating their pregnancies.

DAVIES: So you found a maternity ward.

HAMMERSCHLAG: That's what we think.

DAVIES: How do you do an ultrasound on a shark?

HAMMERSCHLAG: Carefully.

DAVIES: (Laughter).

HAMMERSCHLAG: But - and, you know, once we've got the shark secured on the boat, you know, we would kind of rotate it around so its abdomen was exposed. And we had a special portable ultrasound, high-definition ultrasound with a probe. And just as you would give, you know, someone a sonogram or an ultrasound, where you've got a probe and you're looking on the screen - but one of the cool things because of all the light around you when you're - when you're outside, they have actually got these special goggles that you put on your eye. They kind of look like these virtual reality goggles that you wear. That sees in kind of real time what the probe is looking at. So while you're moving that probe around the abdomen, in the uterus area of the tiger sharks, you're actually seeing that image.

DAVIES: So let's talk a bit about these animals. How long have sharks been around on the planet?

HAMMERSCHLAG: Sharks have been around on the planet, in some way or another, over 440 million years. That's 200 million years or so prior to any dinosaur walking the face of this planet. So these are ancient creatures that have been evolving for hundreds of millions of years to be the super predators that they are.

DAVIES: Sharks are at the apex of a food chain. Does that make them a more valuable subject for study?

HAMMERSCHLAG: Yeah. That's a - that's a great question. And the answer is, absolutely. Many shark species are top predators or live at the - kind of the apex of the food web. And because of that, what happens to the sharks and have - have consequences for the rest of the food chain. And right now, globally, many shark populations are declining due to overfishing. And there's this big concern is - what's going to happen to the rest of the food web, to the whole community of organisms, when you remove that top predator?

DAVIES: Talk about the threats to sharks as a species. Now, are they deliberately fished or are they caught accidentally by long lines that are actually, you know, trying to get swordfish or other species?

HAMMERSCHLAG: Sharks are faced by a number of threats. They're being faced by targeted fishing, in which sharks are being directly targeted and captured, mostly for their fins to actually make shark fin soup, which is an Asian delicacy, particularly consumed in China in the diaspora. However, sharks are being captured, pretty much globally, to supply the shark fin trade and the demand for shark fin soup. Sharks are also caught unintentionally, which is known as bycatch, in fisheries that are targeting swordfish or tuna. And then other threats include, you know, destruction of their nursery grounds. A lot of sharks use shallow water areas like mangroves and seagrass beds close to shore for their nursery grounds. They give birth there, and then the little baby sharks grow up in those safe and shallow water environments.

But a lot of those, particularly here in our area in Florida, are being, you know, destroyed - built up into sea walls and marinas. And, you know, new threats include overfishing of their food that they like to eat. And now issues related to climate change. You know, how are these large sharks going to be dealing with changes in the water chemistry and the temperature?

DAVIES: You have a number, something like 70 million sharks a year are caught and killed. Is that right?

HAMMERSCHLAG: Right now, the latest estimates suggest an average of about 100 million sharks annually are being killed.

DAVIES: Is that mostly for shark fin soup?

HAMMERSCHLAG: Right now, the closest estimate is about an average of 100 million sharks a year are being killed globally. We're not sure exactly how many sharks are being directly targeted for their fins. But work that have actually counted the number of fins in the shark fin market suggest somewhere between 20 and over 70 million sharks annually are making their way through the shark fin trade.

DAVIES: Wow. Why is shark fin soup considered a delicacy?

HAMMERSCHLAG: It's mainly consumed as a cultural sign of wealth. It's a long-held tradition. It has no color, no taste, no smell in itself. In fact, to the soup itself has to be added, you know, chicken broth, beef or pork broth just to give it a taste. And many people who consume shark fin soup have no idea that it actually comes from sharks or that sharks are in any trouble or are declining as a result.

DAVIES: Are there efforts to control this?

HAMMERSCHLAG: Absolutely. Many countries around the world are taking action to limit the amount of shark finning. And there is a new legislation just proposed in Congress, in the U.S, to actually ban the trade and selling of fins. A shark fin ban was just introduced. That's making its way through Congress. And a lot of other places in the world are placing in regulations. However, you know, shark finning is a global phenomenon and as is the shark fin trade. But there's a lot of efforts to try to promote, you know, more conservation and to lower the demand of shark fin.

GROSS: We're listening to the interview FRESH AIR contributor Dave Davies recorded with Dr. Neil Hammerschlag. He directs the University of Miami's Shark Research and Conservation program. After a break, they'll talk about how common shark attacks on humans really are. And we'll hear from Patti Niemi, percussionist with the San Francisco Opera Orchestra. She brought a couple of her instruments with her. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. I'm Terry Gross. Let's get back to the interview FRESH AIR contributor Dave Davies recorded with Dr. Neil Hammerschlag about his work researching, tagging and tracking sharks. He directs the University of Miami's Shark Research and Conservation program. He's filmed some of the largest of these predators, like the great white shark and tiger sharks.

And he was featured in two episodes of the Discovery Channel's recent Shark Week.

DAVIES: How common are shark attacks on humans?

HAMMERSCHLAG: So shark bites on human are actually quite uncommon. It's quite rare. If you think about how many people are using the water and the other risks, I mean, you have more of a chance of getting struck by lightning. You have more chance of dying from a vending machine falling on you. And you have more of a chance by being bitten by other people in New York City in a year than you do of getting bit by sharks.

So their risk from shark is quite low.

DAVIES: You know, in the movie "Jaws," they introduced this idea of territoriality, that if a shark finds a beach where there's, you know, targets for attack, they'll stay there. Is there something to this?

HAMMERSCHLAG: What I will say is there's something to the fact that sharks are opportunistic and that if there's a good food source for them, you know, I think that they're opportunistically going to take advantage of that food source. However, where those types of movies get it wrong is that sharks don't have any interest in humans as a food source.

Humans are not on the shark's menu. And proof is the fact that how rare shark bite actually is. I mean, there'd be nothing easier for a shark than to kind of patrol the beaches during the summers and eat people if we're on the menu because it would be a pretty easy thing to do.

But the fact that, you know, shark bite is so rare and there's so many people in the water just shows that we're not on the menu.

DAVIES: Do sharks end up in urban areas sometimes?

HAMMERSCHLAG: Yes, so we have a project here in Miami to look at the sharks' movement and health around urban areas and close to Miami including around the port where, you know, there's cruise ships or, you know, right up by Brickell or even downtown in the Miami River.

So we have a pretty significant project right now that we call the urban shark project to really understand the behaviors of sharks around, you know, urban environments.

DAVIES: They're not, like, domesticated like geese that get used to getting fed by people in a park, right? I mean, they don't attach themselves to civilization, do they?

HAMMERSCHLAG: We don't know. But, you know, in some places in the world where fishermen go out for the day and catch, you know, a lot of different fishes and then come back to the marina and clean off their fish, their catch, and then dump the carcasses in the water, they've found that sharks start aggregating around those marinas.

And as long as you're - keep on dumping your carcasses off the marinas, the sharks are going to stay there and do it. So there's certainly places that have found that sharks will, you know, feed and take advantage of those discards, those free meals, if they're being made available to them.

DAVIES: When you've studied sharks in a particular area over time, have you been able to discern individual personalities in sharks?

HAMMERSCHLAG: Absolutely. One of the really neat things is even within a species to see how much individual differences there are in personality. There are sharks that are, you know, really shy. And there's others that are really bold. And it has nothing to do with their length.

You know, you could have two sharks of kind of the same size and some just are much more curious and inquisitive than others and some that are really shy and always keep their distance no matter what you do.

DAVIES: And do you see the same ones more than once so you actually get to know them and identify them?

HAMMERSCHLAG: Yeah so - yeah, there's sharks that I've in - for example, in Tiger Beach that I first dove with in 2003 and have almost on an annual basis seen this shark over the years and have been diving with her up until today and seen her put on a thousand pounds in the process.

And, you know, you can see these really strong personalities where they come in really calm but very curious and, you know, have an absolute, pretty strong personality that you can almost identify the individual, you know, just based on the way they're moving in the water and the way they approach you.

DAVIES: So when you get in the water and a familiar one appears, do you think they're recognizing you and saying, hey, Neil, you're back?

HAMMERSCHLAG: I don't think that they're thinking that for me. But they certainly - I think they know what a, you know, what a diver is in the sense that it's not food. And they certainly - they know the situation of, you know, OK, you're just a diver. You're going to hang out here. But I don't think they recognize me. I'm not there as much.

But, you know, it's pretty cool to be able to jump in the water and say, hey, look, there's Emma (ph) the tiger shark, you know? Oh, there's - you know, we have names for them like Emma, and Jamon (ph) and even one called Pickles (ph) and, you know - hey, look, check it out, it's Pickles or Emma or Jamon - you know? - or Hook (ph) is another one that's pretty common.

And that's kind of cool to be able to do that, you know, over the course of years.

DAVIES: You do a lot of tagging of sharks for research. And I want to talk about that. What tests do you perform? What samples do you take? What do you do to the shark while you have it?

HAMMERSCHLAG: There's actually quite a long procedure. We actually have a lot of different samples and tests that we perform, but we do it over very quick amount of time. If you're watching what we do, it almost looks like a race car pit crew, where the car comes in and all these people kind of descend and do all these different tasks and then quickly sends that race car on its way.

And that's the same thing that's happening with the shark. Immediately once we capture the shark and have secured it, the next thing we'll do is actually put a tag in the shark. And we have several different kinds of tags. We have some that are just identification tags that act like bar codes. There are other ones that are tags that send off - a pinging tag that - actually a transmitter that sends off high frequency sounds that have encoded information that are picked up by underwater receivers or hydrophones.

And then we also use satellite tags that will attach to the shark's fin that will transmit to an orbiting Argo satellite when the sharks are moving through the water column and tell us where those animals are. We also take several measurements of the lengths of the sharks and the girths of the sharks, their body shape, including their tail shape and head shape to see how that changes between species or even within a species as they grow older.

We draw blood from the shark to run several tests on the blood where we're looking at reproductive hormones to get an idea if they're mature. We can get an idea of their diet and their feeding behaviors based on the chemical signature in their blood. We also look at their health through doing some immune work.

And we even look at their energy stores, given this idea of their nutrition.

DAVIES: You spend so much time researching sharks and out on the water interacting with them directly. And I'm wondering how you feel about the, you know, the popular portrayal of sharks, especially in movies? I mean, "Jaws," you know, scared the nation out of the water for years. Do you like that movie?

HAMMERSCHLAG: You know, I'm personally entertained by "Jaws." And I think it's a cool movie. And, you know, I think it's amazing how it put sharks into pop culture.

DAVIES: I have to ask you, do you identify with Hooper, the Richard Dreyfuss character? He's the shark expert.

HAMMERSCHLAG: Yeah, no, I don't. I don't. I guess - I don't really. There are other people that do. And there's a lot of shark people that really like "Jaws." But at the same time, it's really unfortunate that that movie was made because it demonized sharks. And it certainly created - you know, people didn't really care about sharks. It wasn't on people's consciousness.

And now after that movie came out, there's a lot of people who kind of wanted to rid the ocean of sharks and thought that any good shark was a dead shark. And that couldn't be further from the truth. We know now that sharks represent a very small risk to humans and that humans represent a much larger risk to sharks, we're removing them by the tens of millions a year.

And we know now that that's not good for the functioning of marine ecosystems.

DAVIES: In Australia, there's what's called the shark cull, where the idea is to reduce the population of sharks that are considered dangerous to swimmers. Tell us about that.

HAMMERSCHLAG: This is very unfortunate. You know, in Australia right now, due to a bunch of, you know, high-profile shark bites on people that resulted in fatality, there's now pretty much a, you know, nation-wide cull that they are killing sharks, very large sharks. And I think it's very unfortunate because, you know, there's just very little evidence scientifically that that's going to work, unless you can reduce the population to such significant levels.

And it's a shame because a public policy to just go out and kill sharks, you know, I think, is not a very strong one. It's not based in science, not based in conservation. You know, I think right now we need to be shark smart. For people who use the water, who use the beaches, it's not about limiting our sharks or preventing people from going in the water. It's about us using the water more smart.

For people who have looked at trends in shark bites, what they show is that more reflects how people use the water than any behavior about sharks. And for example, you know, in California, shark bites that happen on people are usually surfers before 8:00 a.m. and after 5:00 p.m. And that's not because the sharks prefer eating early in the morning or late in the evening.

It's that that's when surfers go surfing, before and after work. And, you know, this is when there's dark water, when, you know, there's some evidence that sharks are getting more active during that period and feeding and also when it's harder for the sharks to kind of distinguish people from maybe some other prey items like seals.

So I think we need to be more smart about the way we use our water environment and try to reduce our risk by kind of behaving in a shark-smart way rather than trying to eliminate sharks.

DAVIES: Well, Dr. Neil Hammerschlag, thanks so much for speaking with us.

HAMMERSCHLAG: My pleasure. It's been really great.

GROSS: Dr. Neil Hammerschlag directs the University of Miami's Shark Research and Conservation Program. He spoke with FRESH AIR contributor Dave Davies, who is also WHYY's senior reporter. After a break, we'll hear from Patti Niemi, percussionist with the San Francisco Opera Orchestra. She brought a couple of instruments with her. This is FRESH AIR.

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