Short Wave

In 1999 hundreds of gray whales washed up along the west coast of North America. More in 2000. They lost an estimated 25% of their population. But then the whale population recovered and people moved on. Until it happened again in 2019. And 2020, and 2021. It’s still happening today. Host Regina G. Barber dives into this mystery with marine ecologist Joshua Stewart, who explains how scientists like himself solved it – and the tough questions that came up along the way. Check out our Sea Camp series and our limited run Sea Camp newsletter, featuring deep dives into research, cute critters and games! Interested in more ocean mysteries? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Today, guest host Selena Simmons-Duffin is exploring a detail very personal to her: How the number of older brothers a person has can influence their sexuality. Scientific research on sexuality has a dark history, with long-lasting harmful effects on queer communities. Much of the early research has also been debunked over time. But not this "fraternal birth order effect." The fact that a person's likelihood of being gay increases with each older brother has been found all over the world – from Turkey to North America, Brazil, the Netherlands and beyond. Today, Selena gets into all the details: What this effect is, how it's been studied and what it can (and can't) explain about sexuality. Interested in the science of our closest relatives? Check out more stories in NPR's series on the Science of Siblings. Email us at shortwave@npr.org — we'd love to hear from you. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Paleontologists have often determined how old a dinosaur was by counting the growth rings in its bones. Just like with trees, it was thought that each ring corresponded to a single year of age. But researchers who studied crocodiles at an outdoor recreation center near Cape Town appear to have poked a hole in that approach. In the crocodiles, which are some of the closest living relatives of dinosaurs, there was more than one growth ring laid down per year. The results contribute to a growing debate over the best way to age animals. Read more of freelance science reporter Ari Daniel’s story here. Interested in more on the future of science? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Teens aren’t getting enough sleep! And a two-decade study suggests it’s getting worse. Scientists found that the number of high schoolers getting insufficient sleep — less than seven hours a night — has increased from 69% to 77%. The throughline? There wasn’t one. Teens had bad sleep habits across most demographics, including race, gender and grade level. The findings were published this week in the journal JAMA. Interested in more science behind recent headlines? Email us your question at shortwave@npr.org. For more about earthquake science – and the Cascadia Fault in particular – check out our recent episode on the Pacific Northwest’s Big One. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

In his role as Secretary of Health and Human Services, Robert F. Kennedy, Jr. is changing how the United States approaches vaccines. But those changes aren’t limited to the United States. NPR global health correspondent Gabrielle Emanuel joins Short Wave to talk about two examples of how the global public health landscape may be shifting. First, the United States’ ultimatum to an international vaccine group. Second, the uncertain fate of a vaccine trial. Some researchers are calling the trial a “unique” opportunity, and others are calling it “unethical.” Read more of global health correspondent Gabrielle Emanuel’s work here. Interested in more global health? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

If you’ve been on the internet in the past few weeks, chances are you’ve seen him: a tiny gray-brown monkey dragging a big, stuffed orangutan around Japan’s Ichikawa Zoo. His name? Punch-kun, or Punch for short. His story? Early abandonment by his mother, careful treatment from local zookeepers and instant social media fame. But are all the (human) primates jumping to Punch’s defense justified? And what’s normal for Japanese macaque society, anyway? To find out, NPR’s Katia Riddle chats with psychology professor and animal expert Lauren Robinson. Interested in more animal science? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Lakes are freezing later, thawing earlier and experiencing dramatic temperature swings in between. And all that throws off the delicate balance of life below the surface. And that has a major impact on the roughly 1.7 million ice fishers in the U.S. who spend millions of dollars buying equipment and guide services each year. Producer Berly McCoy explains how scientists are tracking those ecological changes by getting out on the ice — to fish. Interested in more freshwater science? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Over half a billion people live by lakes that freeze over in the winter. But as the climate warms, those lakes are losing whole days of ice cover. Winters are also getting weirder, with more intense temperature swings that lead to multiple freezes and thaws. Those fluctuations make the ice less safe, and more likely for people to fall through as they walk. So, today, producer Berly McCoy gets into how these changes are altering culture, community and safety on the ice – plus, how firefighters train for rescues. This is the first in a two-part series on how lake ice is changing. Check out Monday’s episode for part two! Check out photos from Berly’s reporting trip to Madison, Wisconsin. Interested in more winter science? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. To manage podcast ad preferences, review the links below: See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Folks over 65 are putting in a lot of screen time. In 2019, the Pew Research Center found that people 60 years and older spend more than half their daily leisure time in front of screens, mostly watching TV or videos. Since the pandemic, that screen time has increased. Is addiction on the rise? And what’s the best use of screen time for any of us? We’re parsing out all the questions with Ipsit Vahia, the Chief of Geriatric Psychiatry at McLean Hospital. Interested in more stories about how technology is changing daily life? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Helicopters. Cargo containers. Old washing machines. For years, fishermen dumped this waste into the Gulf of Mexico. But they weren’t just trying to get rid of junk; they were trying to create artificial reefs that would help attract fish. For this month’s Nature Quest, WWNO coastal reporter Eva Tesfaye takes a (metaphorical) dive into the gulf to find out if Alabama’s ocean junkyard is an economic – and environmental – solution. This episode is part of Nature Quest, our monthly segment that brings you a question from a Short Waver who is noticing a change in the world around them. Send a voice memo to shortwave@npr.org telling us your name, location and a question about a change you're seeing in nature – it could be our next Nature Quest episode! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Bring up aliens and a lot of people will scoff. But not everyone is laughing. Around the turn of the century, 3.8 million people banded together in a real-time search for aliens -- with screensavers. It was a big moment in a century-long concerted search for extraterrestrial intelligence. So far, alien life hasn't been found. But for scientists like astronomer Janes Davenport, that doesn't mean the hunt is worthless. It doesn't mean we should give up. No, according to James, the search is only getting more exciting as new technology opens up a whole new landscape of possibilities. So today, we're revisiting our episode on the evolving hunt for alien life. Want more space content? Let your opinion be heard by dropping us a line at shortwave@npr.org! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Almost 15% of adults suffer from a persistent, often intolerable sound... that is literally just in their heads. Why does the brain do this to us? We help one of our listeners get some answers. This is the second episode of a five-part series called The Sound Barrier from our friends at Vox's Unexplainable podcast.Guests: Stéphane Maison, director of the tinnitus clinic at Mass Eye and Ear and Dan Polley, tinnitus researcher at Mass Eye and Ear Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

From TikTok and Instagram influencers to celebrities like Hugh Jackman and Kourtney Kardashian, intermittent fasting has gotten a lot of hype. The diet restricts what time you eat rather than what or how much you eat. The idea is that short periods of fasting cause your body to burn through stored fat reserves. But is that conventional wisdom true? And can it really contribute to weight loss? Regina G. Barber and Rachel Carlson tackle those questions — plus why some researchers are rethinking how to protect people's mental health when talking to chatbots and how ultra-endurance running changes the human body. Have a scientific question you want us to answer? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

The 2026 Winter Olympics are unfolding in Milan and Cortina, and we can’t look away: We’re watching athletes fly down mountains on skis and glide — sometimes slipping and falling — on the ice. Vikram Chib studies performance and how the brain responds to rewards at Johns Hopkins University. And he says rewards aren’t just for Olympians; they’re baked into basically everything humans do. But those rewards and the pressure that comes with them can come at a cost to people’s brains. And even Olympians are human. Sometimes, we crack. So, today, Vikram dives into the science behind choking under pressure. Interested in more Olympics science? Email us your question at shortwave@npr.org – we may cover it in a future episode! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Picture this: You’re at a pretend tea party, but instead of sitting across from toddlers in tiaras, you’re clinking cups with Kanzi—an ape with the incredible ability to communicate with humans. NPR science correspondent Nate Rott talked to some scientists who did exactly that. But these scientists weren’t just having pretend tea parties with Kanzi for fun, they were trying to test the limits of his imagination – because humans’ ability to play out “pretend” scenarios in our heads and guess at the potential consequences of our actions is key to how we live our lives. And we might not be the only animals to do it! For more of Nate’s reporting, plus videos of Kanzi, check out the full story on NPR here. Chris Krupenye’s study can be found here. If you liked this episode, you might also like our episode on bonobos and the evolution of niceness, and what insights monkeys offer us for the evolution of human speech. Interested in more science about our brains and their abilities? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Early last year, a hundred researchers, clinicians and other experts on HIV discussed the development of an innovative vaccine that could prevent the disease. But just as the meeting was about to wrap up, the mood darkened. A new executive order signed by President Trump on Inauguration day had frozen all foreign aid, pending a review. Soon, DOGE would begin its decimation of USAID — and with it, this vaccine trial. That is – until the South African researchers came up with a new plan. Read more of freelance science reporter Ari Daniel’s story here. Interested in more on the future of science? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

The evolutionary purpose of kissing has long eluded scientists. Smooching is risky, given things like pointy teeth, and inherently gross, given an estimated 80 million bacteria are transferred in a 10 second kiss. And yet, from polar bears to humans, albatrosses and prairie dogs, many animals kiss. So, what gives? Evolutionary biologist Matilda Brindle tells us the sordid details driving this behavior, what distinguishes different kinds of kissing and whether culture has anything to do with why people kiss. Interested in more of the science behind love and connection? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

It seems like artificial intelligence is everywhere in our virtual lives. It's in our search results and our phones. But what happens when AI moves out of the chat and into the real world? NPR science editor and correspondent Geoff Brumfiel took a trip to the Intelligence through Robotic Interaction at Scale Lab at Stanford University to see how scientists are using AI to power robots and the large hurtles that exist for them to perform even simple tasks. (encore) Read Geoff's full story. Interested in more AI stories? Email us your ideas at shortwave@npr.org.Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Watching a ski jumper fly through the air might get you wondering, “How do they do that?” The answer is – physics! That’s why this episode, we have two physicists – Amy Pope, a physicist from Clemson University and host Regina G. Barber – break down the science at play across some of the sports at the 2026 Winter Olympics. Because what’s a sport without a little friction, lift and conservation of energy? They also get into the new sport this year, ski mountaineering - or “skimo” as many call it - and the recent scandal involving the men’s ski jump suits. Interested in more science behind Olympic sports? Check out our episodes on how extreme G-forces affect Olympic bobsledders, the physics of figure skating and the science behind Simone Biles' Olympic gold. Also, we’d love to know what science questions have you stumped. Email us your questions at shortwave@npr.org – we may solve it for you on a future episode! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

In 1928, a chance contaminant in Scottish physician Alexander Fleming’s lab experiment led to a discovery that would change the field of medicine forever: penicillin. Since then, penicillin and other antibiotics have saved millions of lives. With one problem: the growing threat of antibiotic resistance. Today on Short Wave, host Regina G. Barber talks to biophysicist Nathalie Balaban about the conundrum — and a discovery her lab has made in bacteria that could turn the tides. Check out our episodes on extreme bacteria in Yellowstone and the last universal common ancestor. Interested in more science behind our medicines? Email us your question at shortwave@npr.org. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. This episode was produced by Berly McCoy, edited by our showrunner Rebecca Ramirez and fact checked by Tyler Jones. Jimmy Keeley was the audio engineer. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy