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National Geographic
a day ago
- Science
- National Geographic
This animal has a built-in taser to stun sharks
Researchers have documented Gulf torpedo rays (Torpedo sinuspersici) using electric shocks to deter large sharks. Photograph by Andy Murch, Nature Picture Library Electric rays are staying out of the stomachs of sharks by shocking them—with up to 200 volts. With powerful jaws and high levels of resistance to toxins, big-bodied sharks such as tiger sharks and great whites can eat just about anything. Sea snakes venomous enough to kill a human with one bite and stingrays armed with six-inch spines are light snacks for these apex predators of the ocean. Scientists have long believed that no marine creature is safe from a large, hungry shark, but at least one group of animals has evolved an effective means of evading shark digestion: electric rays. In a study published last month in the journal Ethology, researchers found that electric rays can scare away both tiger and white sharks by zapping them with powerful electric discharges. While electric rays are known to use their built-in tasers for hunting, this is the first study to show that they also use them for self-defense. "I wouldn't have initially thought that the electric discharge these animals produce would be that effective as a deterrent against predators. But now I'm quite convinced that it may be a very effective defense,' says Yannis Papastamatiou, an ecologist at Florida International University who studies sharks and other marine predators and led the new analysis. A shocking power Found in temperate and tropical oceans around the world, most electric rays measure less than three feet long. But some, like the Atlantic Torpedo Ray, can grow up to six feet (1.8 meters) and weigh up to 200 lbs (90 kg). The largest among these rays can produce electric discharges over 200 volts, which is more than enough to knock a human off their feet. When stimulated by the rays' nervous system, kidney-shaped organs on either side of their head release charged ions—usually to zap a smaller animal for dinner. Magazine for all ages starting at $25/year (Want to learn more about rays? Here are five fun facts.) Electric rays are also known for not shying away from people and large sharks, says Papastamatiou, who is also a National Geographic Explorer. 'Generally, if you're that bold, it's because you're pretty confident in your defensive capabilities," he says. Papastamatiou saw their boldness on full display for the first time while studying great white shark feeding behavior off the coast of Mexico's Guadalupe Island in 2018. He and his colleagues had attached cameras to the dorsal fins of six sharks. In one video, a great white shark approached a Pacific electric ray in the water column. As the shark got within striking distance, the ray appeared to cup its pectoral fins, the posture it typically assumes when zapping its prey. 'The shark suddenly went ballistic and shot up,' recalls Papastamatiou. 'Something had really disturbed it." Two minutes later, the shark returned, but this time it swam right past the ray, perhaps having learned its lesson. All sharks have a unique sensory system that allows them to detect the weak electrical fields produced by living organisms. That makes them extremely sensitive to electricity. But sharks' tendency to eat anything—despite the danger—made the researchers skeptical that what they'd seen might be a coincidence. Then in 2024, a scuba diving instructor named Ali Ansaar captured a similar scene in Fuvahmulah, Maldives, between a Gulf torpedo ray and a tiger shark. This footage, Papastamatiou says, convinced him that what he'd seen wasn't a fluke. Diver Ali Ansaar filmed a Gulf torpedo ray warding off a tiger shark in the Maldives. As part of this study, Papastamatiou and his colleagues re-examined past footage, including an experiment they had conducted in the late 1990s on Pacific electric rays off Palos Verdes, California, and found more examples of the behavior. To observe the differences between predatory and defensive zaps, the team had either offered the Pacific rays freshly speared fish or prodded them on the back with a rod. The rays emitted similarly strong electrical discharges in response to both stimuli, but the poking elicited shorter and more rapid discharges. "If they're doing it for defensive reasons, it makes sense to put out one very quick blast,' says Papastamatiou. 'These animals essentially have a battery, and like any battery, it takes a while to recharge." Lessons in shark deterrence Because this study only involved Pacific electric rays and Gulf torpedo rays, more work is needed to determine if all electric rays are capable of deterring large sharks. The ability of an electric ray to send a shark packing likely depends on its size, says Dave Ebert, a shark scientist at San Jose State University who was not involved with the study. Ebert has found other species of torpedo rays in the bellies of big sharks. 'I think if they're [small enough] sharks can probably eat them,' he says. Small or juvenile rays may not produce enough electricity to deter sharks, while a zap from a larger ray might be enough to escape their jaws—literally. Ebert has also seen torpedo rays sporting big shark bites. 'You could tell from the bite mark that the shark let go.' The study's authors believe their findings not only change what we know about the defensive capabilities of electric rays but also add credence to the idea that zapping large sharks with electric currents is an effective means of deterring them—a lesson that could help humans design better methods to keep sharks away, too. (Here's how to stay safe if you're swimming with sharks.) But more than anything, the behavior suggests that electric rays are not to be underestimated. "Electric rays can pack a punch,' says Ebert. 'They generally don't attack, but if you tease them, they will stun you."
National Geographic
2 days ago
- Entertainment
- National Geographic
How Reyhaneh Maktoufi transforms science through story
Reyhaneh Maktoufi loves a good story. She uses it to make sense of the world. Her own storytelling style leans into humor. 'As most people who are artists will tell you, I often scribbled in a notebook, doodling. Eventually, I saw that my bad drawings resonated with people,' she says. Sometimes the stories she tells are visual — comics and animations that break down complex concepts into digestible and entertaining narratives. Other times she's a writer and orator. 'I am an alien,' she declared in Maktoufi fashion from the TEDx stage in 2017, then turning a technical glitch with her slides into an impromptu reflection on her life as an immigrant. In front of the live audience she improvised that the glitch was attributable to her extraterrestrial 'powers,' and used the moment to explore how her Iranian-American identity shapes her work bridging scientific communities and the public. Maktoufi is a science communication specialist, social science researcher and National Geographic Explorer who obtained her doctorate in media, technology and society with a focus on science. Her start in bridging the gap between scientific and common language seven years ago at the Adler Planetarium Space Visualization Lab was, as she puts it, 'the perfect environment for an alien,' surrounded by space images, moon rocks and in a place 'not obsessed with national boundaries,' she explains. Here, she began a journey of investigating a deceptively simple question: What makes people curious about science? She aims to make scientific knowledge more accessible by humanizing important and often complex work. 'Numbers matter a lot, but we have to make them imaginable and tangible.'
Metro
2 days ago
- Entertainment
- Metro
‘I swim with sharks without a cage but I'm not an adrenaline junkie'
To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Great white sharks are widely regarded as one of the world's most terrifying predators… but Bertie Gregory is determined to rewrite the narrative. The 31-year-old National Geographic Explorer has seen it all. Whether working with Sir David Attenborough on his acclaimed Planet Earth series, facing down arctic conditions or getting up close and personal with a lion, the wildlife filmmaker's immense respect for the natural order is at the forefront of everything he does. So when his focus shifted to the population of great white sharks (of Jaws fame) at South Africa's Plettenberg Bay there was no question that he would try to meet them in the water, without the protection of a cage. When I ask Bertie why during a Zoom call ahead of the premiere of his TV documentary Sharks Up Close with Bertie Gregory, it's immediately evident this was far from a reckless decision, no matter how terrifying it sounds to the average person. He explains to Metro: 'So with many shark species using a cage is pointless. But there's some sharks, like great whites, that people traditionally have dived [to] using a cage. 'Now, a shark doesn't want to swim near a big metal box, so in order to make [them approach] you have to put a lot of bait into the water.' Here's where the catch (of the day) comes in. 'As soon as you do that, you're not filming the sharks behaving naturally, because the shark is attracted to the bait that wasn't there before. I'm all about filming natural behaviour so instead I chose not to use the cage,' he concludes. Bertie's quick to correct my assumption that this was an 'andrenaline junkie stunt', affirming: 'That's not what drives me,' and crediting an 'amazing team' who analyse the 'right conditions' to make it safe. If there's one message that rings out during our chat, it's that for sharks, humans are 'not on the menu'. Nonetheless, Bertie sheds some light on why fatal attacks may happen among humans and how to avoid them. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video 'Great white sharks attack people because of a case of mistaken identity,' he explains. 'So if you get in the water when the water is very clear, you don't behave like their prey, you don't let them sneak up on you, you're not going to be on the menu. That was really the key,' the animal lover shares. In his hot-heeled pursuit of a great white in his docu-series, he and his crew stumble across what he calls a 'shark cathedral', which in the documentary looks like dark cavern teaming with the creatures. '[It] felt like getting in a time machine and going back millions of years. There was this very narrow little alleyway that we were swimming down, then the cave revealed itself full of those big spotted, ragged-toothed sharks (aka Raggies),' he recalls with glee. The great white has, on average, 300 teeth, weigh between 4,000-7,000 pounds and are 16 to 20 feet in length with an estimated lifespan of 70 years. Their torpedo shaped bodies allow them to swim around 25km per hour, and even push 50km per hour in some circumstances. Although a fierce predator near the top of the food chain, great whites are categorised as a vulnerable species. Estimates predict there are somewhere between 3,000 to 6,000 great white sharks left worldwide. Their diet consists mainly of seals, fish and smaller shark species – humans are not considered prey. Per the Natural History Museum only 17% of unprovoked great white shark attacks have proved fatal since records began in 1580 – even though they have one of the highest bite forces of any living animal. Needless to say, encountering this shark species is not for the fainthearted. 'Raggies have a really terrifying mouth. They're full of hundreds of these needle-like sharp teeth that pour out of their mouth. There's something in the back of your head going: 'Hang on, there are loads of these terrifying mouths swimming around. Is this a good idea?'' he says. 'But actually, I know from experience and knowing my shark biology that we are not on the menu. So actually, it's just an amazing thing to witness. 'When we were swimming in that cave, the hairs on the back of my neck stood up not because I was scared, just because I was so in awe of seeing all these sharks together.' As someone who would choose the sofa over scuba gear any day, I can't get my head around it – but for Bertie, hanging out with sharks is far from the greatest danger he faces. 'The most dangerous animal we encounter on every shoot is always humans. To alter wild animal behaviour, we need to alter human behaviour, so I would say all my scariest encounters have always been with humans,' he says, adding that the 'physical environment' comes a close second. While Bertie might educate his viewers on the natural world, he also learnt a lot himself during filming, such as when he interacted with experts on great white sharks like Lacy Williams. Lacy informed him that far from being 'untouchable predators', the great white is not 'invincible'. In fact, at one point, we see some jaw-dropping footage of a killer whale annihilating a great white. Bertie has no doubt that the famed shark blockbuster Jaws (which came out 50 years ago) has a lot to do with our misconception of this species, even if he gracefully concedes it 'got us talking about sharks'. 'What's annoying to me is that 50 years on – now we know what we know – it is unacceptable to make a film where you paint sharks in the same light that they did before,' he says. 'Shame on the people that now make big blockbuster Hollywood movies demonising sharks. Let's move on. We need to be worried for sharks, not about sharks,' he condemns, reiterating that a thriving shark community is vital for a healthy ocean – and by extension the health of humans. Sharks face threats not only from killer whales but also from people, with their prey being over-hunted and their home being polluted. 'All I'd say is advocate for a healthy ocean. That can be anything from not throwing rubbish into the sea to voting for people that care about the oceans,' he says about everyday actions we can do. More Trending By the end of the documentary, his aim to dive with a great white remains unachieved due to poor conditions and the fact that the great white never enters diveable waters, but that hardly puts him off. 'Would you give it another go?' I ask. 'Oh yeah. It was perfect because it meant we had a really cool film and it means I've got an excuse to try all over again,' he responds without hesitation. View More » Sharks Up Close with Bertie Gregory is now streaming on Disney+ and airs today at 8pm on Nat Geo Wild Got a story? If you've got a celebrity story, video or pictures get in touch with the entertainment team by emailing us celebtips@ calling 020 3615 2145 or by visiting our Submit Stuff page – we'd love to hear from you. 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National Geographic
2 days ago
- National Geographic
These flamboyant birds are the 17,000th species to enter Nat Geo's Photo Ark
Stunning photos of birds of paradise show evolution at its most extravagant. A growling riflebird, a type of bird of paradise, seen at Port Moresby Nature Park in Papua New Guinea. Photographs by Joel Sartore/National Geographic Photo Ark Birds-of-paradise have captivated the planet with their elaborate plumage and idiosyncratic mating dances. Some species appear to shape-shift as they elongate plumes of feathers, fan their wings, or even hang upside down from a tree branch like a bat. There are about 40 species in the birds-of-paradise family, and all are native to either Papua New Guinea, its surrounding islands, or Australia. 'They're like no other birds on earth,' says Joel Sartore, National Geographic Explorer, photographer, and creator of Photo Ark. Since 2006, Sartore has been traveling the globe in a bid to document as many species as humanly possible. And as of this writing, he has approached a number that once seemed unthinkable—17,000 species lovingly coaxed into posing for his camera. Usually, Sartore and his team select one species to highlight as the milestone, but with birds-of-paradise, he says, 'It was just impossible for us to choose.' Recently returned from a trip to Port Moresby, Sartore tried to convey what it was like to sit in the presence of so many of these flamboyantly feathered creatures. 'Everything was interesting to me,' says Sartore. 'They were really calm, all of them, and usually if a bird's calm in my tent, they're pretty smart.' He recalled one bird-of-paradise in particular—an iridescent turquoise and purple bird known as the trumpet manucode (Phonygammus keraudrenii mayrii)—that stared right back at him with its huge, cherry-red eyeball. 'He's seeing himself in the reflection of the light lens filter,' explains Sartore. This is one of the goals of every shoot Sartore does with his simple backgrounds and closeup approach: 'We go with the black-and-white backgrounds to eliminate all distractions and look animals in the eye. It also gives all animals an equal voice, because there's no size comparison,' he says. 'This little king bird-of-paradise,' says Sartore of a bright-red species only slightly larger than a dollar bill, 'he's as big as an elephant.' A trumpet manucode, Phonygammus keraudrenii mayrii, photographed at Port Moresby Nature Park. Looking across the assortment of birds featured here, you'll notice that each species is vastly different from the others, either in color, shape, or feather arrangement. And when these males start to strut for the local females, you'll see that each species also has its own way of wooing the opposite sex. So how did all these closely related birds become so strikingly different? 'Evolution by sexual selection has 'permitted' the evolution of extravagant feathers and behaviors because the fruit they eat is abundant, and the predators that often counterbalance extravagant evolution are absent,' says Edwin Scholes, an ornithologist, and founder and leader of the Cornell Lab's Birds-of-Paradise Project. Interestingly, while it's the male birds and their fancy feathers we tend to focus upon, it's the female birds-of-paradise that are doing the choosing—which means they're the ones actually responsible for the evolution of such extraordinary traits. Habitat and geography also play a role, of course. 'Birds-of-paradise are sedentary forest dwellers and don't disperse or migrate long distances, so even a lowland river valley is a barrier to a montane species. And none fly over open water to islands,' says Scholes. Separated from each other and unencumbered by predators, birds-of-paradise have been free to break off into ever more enchanting species. Some have incredibly oversized features, such as the ribbon-tailed astrapia, which has tailfeathers three times as long as its body. Others, such as the superb bird of paradise, can make their feathers click while dancing. And the growling riflebird? It's known for its, well, growl—something you definitely don't hear every day from a bird. One species, the lesser superb bird-of-paradise, has even been shown to sport feathers that absorb around 99.95 percent of all visible light—a quality scientists call ultrablack or superblack. Add it all up, and Scholes says birds-of-paradise are 'some of the most beautiful, bizarre, and diverse [birds] on the planet.' The good news for these fantastic birds is that they are doing better than many other species found in the Photo Ark. 'Thankfully, no species are currently in the critically endangered category,' says Scholes, though he admits some need more thorough assessment. While none of the species shown here are considered endangered, around one-fifth of all birds-of-paradise species are listed as either vulnerable or near threatened. 'The species that are most at risk or most vulnerable are those that are found only on relatively small islands just offshore from mainland New Guinea, and some that are found at the higher elevations of isolated mountain ranges,' says Scholes. Overall, Sartore says he hopes the images in the Photo Ark will remind people that there is so much life on this planet worth saving. 'We'll go wherever we can to just show people what life was all about and hopefully it makes a difference,' he says. 'That's kind of the whole point—just get people's attention, get them to think about something other than politics and sports for a little bit.' 'And that as these species go away,' says Sartore, 'so could we.'
eNCA
7 days ago
- eNCA
Authorities search for solution as homes get swallowed by sinkholes
CENTURION - Sinkholes are posing a major safety threat around parts of Gauteng. They have swallowed homes in Khutsong, Ekurhuleni and roads have been collapsing in Centurion in east of Tshwane. A significant part of Gauteng contains dolomite, which can dissolve in water and lead to surface collapse. It is a known hazard. This rock according, to Tebogo Makhubela, a National Geographic Explorer, is billion years and covers almost a two third of the province on both surface and sub-surface. This dolomite does not just dissolve on its own another contributing factor is excessive water that affects the rock. This can be from rain but also water from sewage systems, leaking taps. Makhubela said. Geologically speaking there are a lot of areas globally that are not ideal for building infrastructure and residential buildings but this is where civil engineering comes in.
