RENEE MONTAGNE, HOST:
Okay. Want to get away? About this time of year a trip to a sunny beach with warm water and a gentle surf is a very nice thought. But one might want to think twice before actually wading into the surf. NPR's Jon Hamilton reports on a sea creature that can transform a beach vacation into a world of pain.
JON HAMILTON, BYLINE: No, this is not a story about sharks which attack maybe a few dozen people each year. This is a story about stingrays - timid, shellfish eating cousins of the shark that aren't looking to attack anyone. Yet every year stingrays inflict excruciating injuries on thousands of swimmers and surfers from the Bahamas to Bahrain to both coasts of the United States.
Last year, one of the victims was Eric Stern. He's a doctor from Washington, D.C. who likes to go surfing in California. Back in August, Stern was near Santa Monica, giving a surfing lesson to his sister. He remembers casually hopping off his board into waist-deep water.
ERIC STERN: The moment my foot hit sandy bottom, just strike. Bam. I mean immediate, instant knife-like pain.
HAMILTON: Stern's first thought was shark.
STERN: Fear taking over, I wasn't thinking stingray. I was thinking, get out of the water.
HAMILTON: Which he did in a hurry. Then Stern checked out the damaged to his foot.
STERN: The bleeding was so pronounced from what appeared to be a two to three inch gash. I still wasn't thinking stingray.
HAMILTON: He wasn't, but the lifeguards were.
STERN: One of them ran down the beach and unwrapped the towel, took a look and said, no, that's a stingray injury.
HAMILTON: The third one they'd seen that day. Stern says by that time his injury wasn't feeling like a bite or a cut anymore.
STERN: The pain had transitioned already to a much deeper, darker migrainous-type pain, almost like if you put your foot or ankle in a vice and twist it.
HAMILTON: In a lab at Cal State, Long Beach, an hour's drive south of where Stern got injured, a scientist named Chris Lowe explains why the pain was so intense. Lowe says the reason is a powerful toxin secreted by the stingray's tail.
CHRIS LOWE: That toxin is an amazing vasoconstrictor and it causes blood vessels to constrict, reducing blood flow. And what it does is it causes this intense pain sensation, a throbbing kind of aching pain sensation. And it literally takes hours to go away.
HAMILTON: But Lowe says if you've ever felt that pain, don't blame the stingray. They only sting in self-defense. And he says the round stingray that probably got Eric Stern is especially shy. Lowe just happens to have one in a tank.
LOWE: We can pull this ray out and take a look at it. Would you like to do that?
HAMILTON: Yeah, that would be great.
But first he gives me a quiz.
LOWE: Okay. So we're going to play the game, find the ray.
HAMILTON: That doesn't look like a ray. That doesn't look like a ray. That's a crab 'cause it's crawling sideways. That guy over there?
HAMILTON: No? Which one is it?
LOWE: 'Cause you see, this is the name of their game. The name of their game is disappearing.
HAMILTON: Now I can just barely see a faint outline in the tank's sandy bottom. It's about the size of a dinner plate. I can also make out two eyes and two nostril-like openings called spiracles. Lowe scoops the stingray into a net and shows me how Eric Stern's foot got filleted.
LOWE: So right at the end of the tail is the spine. Trying to do this without getting stung. And you can see it's fully intact. There's the spine there. And it rests in a sheath right at the base of the tail. So when you are to harass this ray or accidentally step on it, it has the ability to quickly flick its tail up. And that barb comes up like an arrow point.
HAMILTON: Piercing your flesh and delivering the toxin. The spines on round rays are maybe an inch long, but Lowe says other stingrays, like the Australian Bull Ray, have spines big enough to kill a person.
LOWE: Those stingrays are enormous. Their spines are the size of a steak knife. They're huge.
HAMILTON: It was Bull Ray on Australia's Great Barrier Reef that killed the wildlife expert Steve Irwin in 2006. Irwin was best known for hosting "The Crocodile Hunter" TV series.
LOWE: Believe it or not, Steve Irwin was not the only fatality. I mean, usually in Australia, maybe about every five or six years or so, somebody is killed by one of those large stingrays.
HAMILTON: There aren't good statistics on stingray injuries, but what data there are suggest that thousands of people are stung each year worldwide and that the number may be rising. Lowe says in some places stingray populations appear to be growing because there are fewer predators, like sharks and seals and sea lions. Also, more and more people around the world are spending time at the beach.
LOWE: I get calls from resort owners on the East Coast, even in the Middle East, where they have really high-end resorts. They have stingrays in those areas. They have had people injured, and they call us up asking us what should they do.
HAMILTON: People have been asking that question for a long time at Seal Beach, which is just a couple of miles from Chris Lowe's lab. Lowe thinks that about 16,000 rays live along just few hundred yards of shoreline here, and the area reports more stingray injuries than any place on Earth, about 400 a year.
Take a stroll down Seal Beach and there's a good chance you'll run into this guy.
MICHAEL PLESS: Hi. I'm Michael Pless from M&M Surfing School.
HAMILTON: With a truck up there.
PLESS: With a truck up there, yes. I've been here for 30 years.
HAMILTON: Ever been stung?
PLESS: I'm known as the king of stingray stings. I've been stung 21 times.
HAMILTON: The parking lots around Seal Beach have signs warning about stingrays. But Pless says he still gives all of his students a special lesson in how to do the stingray shuffle.
PLESS: I generally tell the students to shuffle your feet. If you step on something gushy, move your feet very quickly, jump up, okay? Otherwise the stingrays will sting you.
HAMILTON: The lifeguards at Seal Beach also try to warn bathers. But Nick Bolin, a marine safety officer, says a lot people still learn about stingrays the hard way.
NICK BOLIN: Usually our tower guards will spot them seconds after they've been stung because they'll come hopping out of the water and usually send a person from the group to run up towards the lifeguard tower.
HAMILTON: Bolin says then, assuming the wound isn't too serious, the lifeguards begin a familiar routine.
BOLIN: We'll take them back to our lifeguard headquarters where we have a dedicated lifeguard assigned to a stingray shift and we soak the foot in hot water until their pain subsides enough that they can go on their own way.
HAMILTON: Bolin says when the beach is busy and the tide is low, there may be dozens of victims.
BOLIN: We've had days where our hot water heater actually can't even keep up with the amount stings.
HAMILTON: Scientists say hot water is critical because heat neutralizes the stingray toxin, and that's about the only way to reduce the pin. Just take it from Eric Stern, the surfing doctor.
STERN: The moment you take your foot out of the hot water, the pain just shoots back up within, you know, five to 10 seconds, and the moment you put it back in the hot water, another five to 10 seconds and it's tolerable again. It's really quite remarkable.
HAMILTON: Unfortunately for Stern, several hours of hot water treatment wasn't the end of his stingray adventure. The gash on his foot had to be sewn up at a local emergency room. And once the wound healed, Stern realized he had another problem.
STERN: I began to notice that I didn't have any sensation in the dorsum or top of my foot around the base of my fourth and fifth toes.
HAMILTON: The sting had caused nerve damage, and Stern eventually needed surgery. But he's better now and ready to get back in the waves.
STERN: I'm already eagerly awaiting my next trip to Southern California. But this time I think I'm going to stay on my board until I'm out in deep waters.
HAMILTON: In the meantime, Stern is helping Los Angeles County lifeguards write an informational pamphlet they can give to people who get stung. Jon Hamilton, NPR News.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.