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Elise Hu
It is summer where I live and luckily I live near the Pacific Ocean. As the weather continues to heat up, I'm spending more time at the beach. It always makes me wonder what's going on under the water. From the deep sea to the shoreline, the ocean is teeming with creatures that are stranger, smarter and more surprising than most of us could ever dream up. For July's TED Talks Daily Playlist, we have gathered five of our favorite talks that dive into the awe inspiring and occasionally mind bending creatures from orcas to kinky fish that live beneath the waves. Happy listening. You're listening to TED Talks Daily where we bring you new ideas to spark your curiosity every day. I'm your host, Elise Hu. It turns out the ocean plays host to some of the wildest, weirdest, and most surprisingly consequential sex lives on the planet. Yes, you heard me right, and most of us have no idea. In this talk, marine scientist Mara J. Hart takes us deep into the reproductive strategies of everything from parrotfish to lobsters to anglerfish and makes the case that understanding them isn't just fascinating, it's urgent because human behavior is quietly disrupting these intimate affairs in ways that affect our food, our health and our shorelines. It turns out your own wellness depends, at least in part, on the healthy sex lives of fish. That's coming up right after a short break. This episode is sponsored by Kohler Smart Toilets. The objects we interact with most are often the ones we notice least. But what if the most overlooked space in your home could be the most considered? Kohler Smart Toilet challenges that assumption. Their Vail Smart Toilet is a sculptural silhouette that isn't just intentional, it's a philosophy that design changes everything. The kohlervale Smart Toilet is sleek with a rounded shape that's more like architecture than just plumbing. And it goes beyond looks. The touchscreen control controls and customizable cleansing features offer a level of comfort and cleanliness that exceeds expectations. It's all about elevating those ordinary daily rituals into something extraordinary through thoughtful design. Kohler has been pushing these boundaries for over 150 years, mastering that balance of stunning form and high performance function that's a long time to get it right, and it shows in every detail. Experience the difference of Kohler Smart Toilets. Find out more@kohler.com this episode is brought to you by Dell. Back to school starts now. Get long lasting battery life on the Dell XPS laptop powered by Series 3 Intel Core, so you can work from anywhere now starting at $699 with exclusive student pricing starting at 599 and it's lightweight, portable and packed with enough processing power to make multitasking a breeze. So say goodbye to distractions and hello to more free time because you finished your work for faster. Complete your setup with savings on select monitors and more. Must have electronics and accessories, limited time deals and free shipping on PCs and more await you@dell.com deals that's Dell.com deals. This message is brought to you by Apple Card. Apple Card puts the power of titanium in the palm of your hand. What does that mean? It means the power to earn unlimited daily cash back on your purchases every day. It means a materially different credit accepted anywhere in the world. MasterCard is accepted. Ditch the plastic upgrade to titanium. Apply in the wallet app on iPhone today. Subject to credit approval. Apple Card is issued by Goldman Sachs Bank USA, Salt Lake City branch terms and more@applecard.com. And now our TED Talk of the Day.
Mara J. Hart
Right now, beneath a shimmering blue sea, millions of fish are having sex. And the way they're doing it and strategies they're using looks nothing like what we see on land. Take parrotfish. In this species, all fish are born female. Then later in life, she can transition into a male. But it's not just a spectacular wardrobe change. Her body can reabsorb her ovaries and grow testes in their place. In just a few weeks, she'll go from making eggs to producing sperm. It's pretty impressive. And in the ocean, it's also pretty common. In fact, I bet nearly all of you have at some point had a seafood dish made up of an individual that started life as one sex and transitioned to another. Oysters, grouper, shrimp. Seeing some heads nodding? Yeah. But not all fish that change sex start as females. Those clownfish we know from Finding Nemo, they're all born male. So in the real world, when Nemo's mother died, Nemo's dad, Marlin, would have transitioned into Marlene, and Nima would have likely mated with his father turned mother. You can see, You can see why Pixar took a little creative license with the plot line, right? So sex change in the ocean can happen in either direction and sometimes even back and forth. And that's just one of the many amazing strategies animals use to reproduce in the ocean. And trust me when I say it's one of the least surprising. Sex in the sea is fascinating. And it's also really important, and not just to nerdy marine biologists like me, who are obsessed with understanding these salty affairs. It matters for all of us today, we depend on wild caught fish to help feed over 2 billion people on the planet. We need millions of oysters and corals to build the giant reefs that protect our shorelines from rising seas and storms. We depend on medicines that are found in marine animals to fight cancer and other diseases. And for many of us, the diversity and beauty of the oceans is where we turn for recreation and relaxation and our cultural heritage. In order for us to continue to benefit from the abundance that ocean life provides, the fish and coral and shrimp of today have to be able to make fish and shrimp and coral for tomorrow. To do that, they have to have lots and lots of sex. And until recently, we really didn't know how sex happened in the sea. It's pretty hard to study, but thanks to new science and technology, we now know so much more than even just a few years ago. And these new discoveries are showing two things. First, sex in the sea is really funky. Second, our actions are wreaking havoc on the sex lives of everything from shrimp to salmon. I know it can be hard to believe. So today I'm going to share a few details about how animals do it in the deep, how we may be interrupting these intimate affairs, and what we can do to change that. So remember those sex changing fish. In many places in the world, we have fishing rules that set a minimum catch size. Fishers are not allowed to target tiny fish. This allows baby fish to grow and reproduce before they're caught. That's a good thing. So fishers go after the biggest fish. But in parrotfish, for example, or any sex changer, targeting the biggest fish means that they're taking out all the males. That makes it hard for a female fish to find a mate. Or it forces her to change sex sooner at a smaller size. Both of these things can result in fewer fish babies in the future. In order for us to properly care for these species, we have to know if they change sex, how and when. Only then can we create rules that can support these sexual strategies, such as setting a maximum size limit in addition to a minimum one. The challenge isn't that we can't think of these sex friendly solutions. The challenge is knowing which solutions to apply to which species. Because even animals we know really well surprise us when it comes to their sex lives. Take Maine lobster. They don't look that romantic or that kinky. They are both. During mating season, female lobsters want to mate with the biggest, baddest males. But these guys are really aggressive and they'll attack any lobster that approaches male or Female. Meanwhile, the best time for her to mate with the male is right after she's molted, when she's lost her hard shell. So she has to approach this aggressive guy in her most vulnerable state. What's a girl to do? Her answer, spray him in the face repeatedly with her urine. Under the sea pee is a very powerful love potion. Conveniently, lobsters bladders sit just above their brains and they have two nozzles under their eye stalk which they can shoot their urine forward. So the female approaches the male's den and as he charges out, she lets loose a stream of urine and then gets the hell out of there. Only a few days of this daily dosing is all it takes for her scent to have a transformative effect. The male turns from an aggressive to a gentle lover. By the week's end, he invites her into his den. After that, the sex is easy. So how are we interrupting this kind of kinky courtship? Well, the female's urine carries a critical chemical signal that works because it can pass through seawater. And lobsters have a smell receptor that can detect and receive the message. Climate change is making our oceans more acidic. It's the result of too much carbon dioxide entering seawater. This change in chemistry could scramble that message, or it could damage the lobster's smell receptors. Pollution from land can have similar impacts. Just imagine the consequence for that female if her love potion should fail. These are the kinds of subtle but significant impacts we're having on the love lives of these marine life. And this is a species we know well. Lobsters live near shore, in the shallows. Dive deeper and sex gets even stranger. Fanfin anglerfish live at about 3,000ft below the surface in the pitch black waters. And the males are born without the ability to feed themselves. To survive, he has to find a female fast. Meanwhile, the female, who is 10 times bigger than the male, 10 times she lets out a very strong pheromone with which to attract mates to her. So this tiny male is swimming through the black waters, smelling his way to a female. And when he finds her, he gives her a love bite. And this is when things get really weird. That love bite triggers a chemical reaction whereby his jawbone starts to disintegrate, his face melts into her flesh, and their two bodies start to fuse. Their circulatory systems entwine and all his internal organs start to dissolve, except for his testes. His testes mature just fine and start producing sperm. In the end, he's basically a permanently attached, on demand sperm factory for the Female. It's a very efficient system. But this is not the kind of mating strategy that we see on a farm, right? I mean, this is weird, it's really strange. But if we don't know that these kind of strategies exist or how they work, we can't know what kind of impacts we may be having even in the deep sea. Just three years ago, we discovered a new species of deep sea octopus where the females lay their eggs on sponges attached to rocks that are over two and a half miles deep. These rocks contain rare earth minerals. And right now there are companies that are building bulldozers that would be capable of mining the deep sea floor for those rocks. But the bulldozers would scrape up all the sponges and all the eggs with them. Knowingly, and in many cases unknowingly, we are preventing successful sex and reproduction in the deep. And let's be honest, dating and mating is hard enough without somebody coming in and interrupting all the time, right? I mean, we know this. So today, while I hope you will leave here with some excellent Barre trivia on fish sex, I also ask that you remember this. We are all far more intimately connected with the oceans than we realize, no matter where we live. And this level of intimacy requires a new kind of relationship with the ocean. One that recognizes and respects the enormous diversity of life and its limitations. We can no longer think of the oceans as just something out there because every day we depend on them for our food security, our own health and wellness, and every other breath we take. But it is a two way relationship. And the oceans can only continue to provide for us if we in turn safeguard that fundamental force of life in the sea. Sex and reproduction. So like any relationship, we have to embrace some change for the partnership to work. The next time you're thinking about having seafood, look for sustainably caught or farmed species that are local and low on the food chain. These are animals like oysters, clams, mussels, small fish like mackerel. These all reproduce like crazy. And with good management, they can handle a bit of fishing pressure. We can also rethink what we use to wash our bodies, clean our homes and care for our lawns. All those chemicals eventually wash out to sea and disrupt the natural chemistry of the ocean. Industry also has to play its part and take a precautionary approach, protecting sexual activity where we know it exists and preventing harm in the cases where we just don't yet know enough, like the deep sea. And in the communities where we live, the places we work, and the country in which we vote. We must take bold action on climate change now.
Elise Hu
That was Mara J. Hart at TedX Mile High in Denver, Colorado in 2019. This talk was originally published in May of 2020. If you're curious about Ted's curation, visit Ted.comCurationGuidelines and that's it for today. TED Talks Daily is a podcast from ted. This episode was produced and edited by our team, Martha Estefanos, Oliver Friedman, Lucy Little, Emma Tobner, and Tanzika Sangarnivong. Additional support from Daniela Ballarazo, Christopher Faizy Bogan, Valentina Bohanini, Banban Chang, Brian Greene, and Lainey Lott. Learn more at Podcasts. I am Elise Hu. Thanks for listening.
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Episode: The Mystery of Sea Creatures (4/5): Are we interrupting the kinky sex lives of fish?
Speaker: Mara J. Hart | Host: Elise Hu
Date: July 18, 2026
This TED Talk, delivered by marine scientist Mara J. Hart, explores the extraordinary and diverse mating strategies of sea creatures—from sex-changing parrotfish and aggressive lobsters to bizarre deep-sea anglerfish. Hart argues that unraveling these intimate secrets is more than scientific curiosity; our behaviors are actively disrupting marine reproduction, with significant consequences for food security, shoreline protection, human health, and the continuing abundance of ocean life. The episode is both eye-opening and urgent, blending scientific wonder with a call for ecological responsibility.
Parrotfish & Sex Change:
Clownfish Reality vs. “Finding Nemo”:
Other Wild Strategies:
Fishing Regulations Gone Wrong:
Lobsters’ Kinky Love–& Chemical Communication:
Bizarre Deep-Sea Mating:
Recent Discoveries & Risks:
Personal Choices:
Societal & Industrial Responsibility:
Memorable Closing Quote:
The talk blends playful humor with urgency and wonder, providing vivid descriptions of animal behaviors (“her body can reabsorb her ovaries and grow testes in their place”) and mixing trivia-worthy facts with pointed commentary on the real risks of human interference. Hart’s tone is enthusiastic, relatable, and passionate about marine life, while her call to action is both practical and inspiring.
For more intriguing tales of the sea and insight into the world’s most surprising species, visit TED’s online resources or continue the TED Talks Daily playlist.