Largest shark that ever lived: Scientists unlock mystery about the megalodon
USA TODAY
The biggest, most formidable shark to have ever roamed the ocean may have been even larger than previously thought, according to a new study.
The research, published Sunday in the journal 'Palaeontologia Electronica,' suggests that the megalodon, which dominated the ocean 3.5 million years ago, was more than three times the size of a great white shark.
The monster shark, depicted in the 2018 sci-fi horror film " The Meg," was previously believed to be between 50 and 65 feet long. But the new study, conducted by researchers in 28 countries, found the megalodon could have reached a whopping 80 feet in length, roughly the size of two school buses.
The study helps confirm the hypothesis that the megalodon was not 'merely a gigantic version of the modern-day great white shark,' as previously thought, said Phillip Sternes, an educator at SeaWorld San Diego and a researcher on the project. Instead, the shark could have closer cousins today.
It also sheds light on the mystery of how the fearsome carnivore may have gone extinct millions of years ago – and the role the smaller great white shark played.
How big was Megalodon?
Scientists have long struggled to determine the size of the megalodon because no complete fossil of the extinct animal has been found. Past studies have estimated the megalodon's length and body shape by comparing it to the great white shark, which has similar large, serrated teeth.
But Sternes said those studies relied on assumptions about similarities between only the two shark species.
The new study compared megalodon fossils with more than 150 living and extinct shark species. It found the megalodon may have had a longer, more slender body resembling that of the modern lemon shark, rather than the great white. It could have ranged between around 54 feet long and 80 feet long, the study suggests.
And that longer length isn't just a fun fact about the fearsome creatures. It could also paint a clearer picture about the way megalodons moved through the water.
Kenshu Shimada, a paleobiology professor at DePaul University in Chicago who led the study, said findings about the megalodon's maybe-slender body align with what scientists already know about other gigantic aquatic animals: Thinner bodies allow long animals to swim more efficiently.
If the megalodon was a similar shape and size to the modern great white shark, that stocky body would 'not allow it to be an efficient swimmer,' to catch prey and survive, Shimada explained.
So what killed the megalodon?
Little is known about how and why megalodon went extinct around 3 million years ago. But the study says the great white shark could have had something to do with it.
The fossil record and 'inferred growth patterns,' suggests that the rise of the great white shark, and the competition it brought, actually helped lead to the demise of the megalodon, the study states.
Researchers are still investigating the megalodon's evolution, but Sternes told USA TODAY one possibility is that the predator's large body might not have been as adaptable as smaller shark species, even if it could swim freely.
'We've learned about how the planet fluctuates with different environmental factors, how life responds to it,' he said. 'Understanding the past can better inform us about both the present and the future for life on Earth.'
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
USA Today
5 hours ago
- USA Today
After dire wolf's return, Peter Jackson wants to bring back this New Zealand bird
Peter Jackson is best known for directing and producing movies such as The Lord of the Rings and The Hobbit films and "The Beatles: Get Back." Now, he's helping direct a project to resurrect long-extinct bird species in New Zealand. An investor in Colossal Laboratories & Biosciences – the private firm that recently brought back a modern-day incarnation of the dire wolf and is working to de-extinct the woolly mammoth – Peter Jackson wanted to see if the biotech company might attempt to spread some of its magic in his home country. "Why aren't you doing the moa, which is a thing that I really care about?" Jackson told USA TODAY he asked the genetics wizards at the company, referencing the species of flightless birds which were indigenous to New Zealand but went extinct about 600 years ago. "I mean, the Tasmanian tiger ... and the mammoth's great, and everything else, but the moa is the thing that I was really passionate about," Jackson said. "And they said, 'sure we'd love to do it'." What is a 'sprite'?: NASA astronaut captures rare phenomenon from 250 miles above Earth Evidence of Jackson's passion about the moa: over the past 20 years or so, the filmmaker and his partner Fran Walsh had amassed a collection of more than 300 moa bones. As Jackson learned more about Colossal – DNA in ancient dire wolf bones helped create a dire wolf genome – he could envision the possible de-extinction of the moa. 'With the recent resurrection of the dire wolf, Colossal has also made real the possibility of bringing back lost species," Jackson said in a press release about the new project. An advisor on the moa project, Jackson helped involve the Ngāi Tahu Research Centre at the University of Canterbury in Christchurch, New Zealand. The centre – established in 2011 to support education for the Ngāi Tahu, the main Māori tribe of southern New Zealand – will direct the project, which also includes animal conservation efforts and the biobanking of other native species for preservation. "Every decision we make along the way in the research and the de-extinction is being led by them and governed and supported by them," said Ben Lamm, CEO and co-founder of Colossal, which is also creating a New Zealand subsidiary of the company. "It's been massively rewarding, because it also affords us the ability to get so much deeper in the culture in a way that we've never even done when we worked with other indigenous groups around the world." What animal is Colossal looking to bring back next? The South Island Giant Moa, so named because it was indigenous to New Zealand's south island. While there were nine distinct species of the wingless moa – including birds the size of turkeys – the South Island Giant Moa stood out, approaching 12 feet tall with its neck outstretched. Considered the world's tallest bird before it went extinct, "it's part of a family of large birds that once inhabited our ancestral tribal territories," said Kyle Davis, a Ngāi Tahu archaeologist who has helped search for moa fossils as part of the project. The Giant Moa was "gigantic," weighing up to 250 kilograms (550 pounds), Paul Scofield, an moa expert and advisor on the project, told USA TODAY. "It was heavily covered in feathers from the head and even down the legs. It had really very massive feet, far more massive than any bird," said Stevens, the senior curator of natural history at Canterbury Museum, which has the world's largest collection of moa bones. A kick from the moa could be deadly, according to Encyclopedia Britannica, which noted the moa fed on seeds, fruits, leaves, and grasses, and laid one large egg of up to 7 inches in diameter. Experts say there were about 150,000 of the tall birds when the Polynesian settlers came to south New Zealand. Within about 150 years, they were extinct, said Mike Stevens, the director of the Ngāi Tahu Research Centre, in the press release. 'During the fourteenth and fifteenth centuries, moa provided meat for sustenance, and bones and feathers for tools and decoration," especially in Te Wāhipounamu (the official Māori name for southwest New Zealand), he said. The Giant Moa remains a symbol for the people of the south island and its potential resurrection fits within the country's many ongoing conservation efforts including the protection and resurgence of the kākāpō, a flightless parrot. Research into de-extinction of the moa will likely shed light on New Zealand's ecological past. "It's really going to answer so many questions about prehistoric New Zealand," Scofield said. "Every single thing we discover about this amazing animal is really going to help flesh out what New Zealand was before humans arrived." So far, Colossal has created a genome of the tinamou, thought to be the closest living relative of the moa. While there's a lot of work ahead, Jackson envisions a natural environment for the Giant Moa to roam when it returns, he said in a promotional video about the project. "We're now at the point where being extinct isn't really the end of the story." Mike Snider is a reporter on USA TODAY's Trending team. You can follow him on Threads, Bluesky, X and email him at mikegsnider & @ & @mikesnider & msnider@ What's everyone talking about? Sign up for our trending newsletter to get the latest news of the day
USA Today
a day ago
- USA Today
Brain-computer interfaces: Unlocking the potential of man and machine
On Sunday's episode of The Excerpt podcast: Brain-computer interfaces promise breakthroughs in restoring lost function and beyond. But they also raise ethical and societal questions about the linking of minds with machines. Dr. Iahn Cajigas, a neurosurgeon at the University of Pennsylvania who has studied brain-computer interfaces and worked with patients using them, joins USA TODAY's The Excerpt to share his insights. Hit play on the player below to hear the podcast and follow along with the transcript beneath it. This transcript was automatically generated, and then edited for clarity in its current form. There may be some differences between the audio and the text. Podcasts: True crime, in-depth interviews and more USA TODAY podcasts right here Dana Taylor: Hello. And welcome to The Excerpt. I'm Dana Taylor. Today is Sunday, July 6th, 2025. It is the fodder of science fiction plots and planting a device into the human brain. The Blockbuster franchise, The Matrix comes to mind. Here in the real world, though it's actually happening, while tiny computers have been implanted into less than 100 brains so far, their impact has been life-changing. Brain-computer interfaces or BCIs have done everything from allowing increased mobility to helping with speech. Could these devices become more mainstream and help the disabled do even more in the future? To dive into all these questions and more, I'm joined by Dr. Iahn Cajigas, a neurosurgeon with the University of Pennsylvania, who studied brain-computer interfaces and worked with patients using them for over three years. Thanks for joining me, Dr. Cajigas. Dr. Iahn Cajigas: Thank you for having me, Dana. Dana Taylor: For someone who's not familiar with these BCIs, can you catch us up on the landscape here? What kinds of things are they helping patients do right now? Dr. Iahn Cajigas: It's a very exciting field. I think the best way to think about brain-computer interface technology is really to think about what the brain does and understand what are the inputs and outputs of the brain, and then understand what can be damaged with injuries of the nervous system, because that's exactly what these devices aim to restore. So as we all know, there's five main senses, right? We have sight, smell, hearing, taste, and touch, and those are the inputs to the brain. And then we have the outputs that the brain, what can the brain do to interact with the world? That's really movement of muscles of the mouth, muscles of the hand to write, muscles of the leg to move. And therefore, what brain-computer interfaces are aiming to do is either helping get signals into the brain to restore some of the senses that have been lost or get signals out of the brain to re-enable patients to interact with the world. Dana Taylor: And without getting too technical, how do they work? Dr. Iahn Cajigas: The main language of the brain is really the electrical activity in individual neurons. And so by understanding what the neurons are trying to do and how these are related to the actions that the individual is trying to perform, we're able to make a translation between the activity in the brain to the output. So for example, if a patient's trying to reach with their arm to grab something, well, we can listen to the neurons in the motor cortex and how they're trying to recruit the muscles that are involved in that reach, and then tell a computer or a robotic arm, "Translate that movement into the movement of a cursor or the movement of a robotic arm that matches what the person's intending to do with their limb." It's really by creating a map that relates the electrical activity of the brain with the actual output that is intended, that we're then able to restore that function. Dana Taylor: I know there are several big name brands in the space right now, including Elon Musk's Neuralink. Apple's recently announced that it's also entering the space with tech that could one day allow a patient to control their iPhone. How do the devices functionally differ, or do they? Dr. Iahn Cajigas: The key is that there are different levels of granularity with which you can listen to the brain. So you can listen to individual neurons or pairs of neurons, or a small number of neurons. These are typically through invasive devices such as the Neuralink device that has multiple threads that are implanted directly into the brain substance to pick up this electrical activity. And then you can listen from very close, like in that case where you can start listening from further away and in less invasive ways. So there are other devices from other companies that sit on the brain surface itself, but yet penetrate the brain. And so listen to the brain activity by interfacing directly to the brain matter and picking up neurons, but at the surface, not deeper into the core of the brain. There are other companies that have implants that listen on the surface of the brain. That is, they do not penetrate the brain itself. These are so-called electrocorticographic BCIs instead of the penetrating BCIs, or non-penetrating BCIs, they can also be referred to. And then there are others that can listen for much further away in a blood vessel and try to pick up the activity in the neighborhood around, say, the motor cortex. So there's different ways to get to the electrical activity, and we don't know what the best way is or what's going to pan out in the long term. So what you see is companies that are taking different strategies to try to listen to the brain at different levels of granularity to see which will be more successful. And it's a really exciting time because all of these companies are gearing up to be close to implanting these technologies in humans in the next few years with some of the companies already having tens of patients implanted and others gearing up for implant within the next year or two. Dana Taylor: You're working with patients who are using BCIs currently at the University of Pennsylvania. What kinds of things are your team studying with this group, and what's been the most surprising discovery? Dr. Iahn Cajigas: It's been very challenging to study BCI over the last 25 years, primarily because it takes patients that have suffered a neurologic injury to be recruited into a study that then requires this permanent invasive implant that goes into the brain. And for the last two decades, we didn't really have technologies that could leave the laboratory. And so these small number of patients, over 60 to 70 patients in the last 25 years, it's been limited what we've been able to do with this. And the pace of understanding the brain, it's been challenging. We've learned a lot, but it's been challenging learning from tens of patients. My lab's approach here at Penn has been, well, we have really unique access as neurosurgeons to the brain. So I do brain surgery often on my patients for other reasons, such as having Parkinson's or tremor, and I typically place electrodes into the brain to help them with these disorders. So the approach of my lab has been we give our patients the opportunity to work with us, part of research for about 20 to 30 minutes during their surgery, where right before we do the critical portions of their surgery, we place a temporary electrode over the motor cortex where their hand area of the brain is, and we temporarily ask them to play games with us like rock, paper, scissors, or reaching tasks. And then we synchronize the activity on the brain surface to the activity of their movement. So they actually, we place special sensors on their hand and on their body, the same things that are used in Hollywood for motion capture. And we've developed ways to synchronize the activity of the behavior with the actual electrical activity on the brain surface so that we can see what this relationship looks like in able-bodied individuals, not patients that are paralyzed. What's really been interesting about doing this in healthy individuals is, one, how excited people are to be able to contribute their time to potentially moving the field forward for others that have neurologic injury. And then just, we've had the opportunity to collaborate with one of the companies that is entering the BCI space where they have a high resolution noninvasive electrode. And so to look at the brain through such a high resolution window as somebody is moving and seeing these incredible patterns of electrical activity, spirals, traveling waves, things that we have never observed before at this level of detail is just phenomenal. We are still in the process of understanding how these patterns actually relate to the behavior being performed and developing methods to help decode what they're intending to do with their arm and hand, like showing us a gesture or reaching to an object. Dana Taylor: What does access to this technology look like today? Is anyone in the movement disordered group eligible? Dr. Iahn Cajigas: So for our surgeries, it's actually all those patients that are undergoing surgery for their movement disorder could participate in this research, and again, it's only 20, 30 minutes during their surgery. For this technology, there are other centers that are using it in other contexts, such as temporarily implanting them in the context of epilepsy surgery or somebody who may have had trauma or intraoperatively for mapping parts of the brain that may be critical during a tumor resection. So there are many institutions that are using this less invasive approach to understand the brain through temporary access to the brain, but in our case, it's open to anyone that's undergoing surgery for their movement disorder. Dana Taylor: What are the biggest hurdles or issues that medical professionals are facing with the technology? Dr. Iahn Cajigas: One is patient expectations. We hear, you've made a reference to the movie The Matrix, and the expectations that are there in lay press, and in the movies, and science fiction, the things that we are learning with these tools today about how the brain represents information related to movement to either help patients restore their ability to speak or move their hands to give them some independence, autonomy, or communication. This is the beginning of understanding that. And as this technology grows, we may be able to do more things, but I think that understanding where we are is very important. Another limitation is going to be access. I mean, these are medical devices that are going to have a cost associated with them, and it becomes challenging that as clinicians, I think we all aim to get patients things that are able to help them, but there's going to be a problem about equitable access that is going to occur, and we need to be careful with that as a society and make sure that we make it available to everybody that can benefit from it when the technology is mature enough. Dana Taylor: Are there any downsides for patients? Dr. Iahn Cajigas: Well, again, a lot of the patients that are candidates for this technology are quite debilitated. They're either, say, in a locked in state where they are unable to speak or move. They could be paralyzed from a spinal cord injury or from a stroke. So they've already undergone or had a neurologic event that has affected their life. These are surgical tools. All the implants I'm referring to are permanent implants. And so these are all surgeries that have small but inherent risks that need to be balanced as well on a patient by patient basis. So these include things like infection, bleeding, additional neurologic injury. If something were to happen during a surgery, and it really has to be this dialogue between the physician and the patient to find the best option for their condition to improve their quality of life. Dana Taylor: Some writers and journalists have written about this technology with an eye toward a future where even abled people are able to use BCIs to just do more, think faster, access their subconscious, the stuff really of science fiction, as you said. What are your thoughts on this as a medical professional? Dr. Iahn Cajigas: Yeah, I think as somebody who loves science fiction, I think it's the sorts of things that as a child got me excited about technology in the brain and understanding things. But I think as a medical professional today, I think we have to understand the risks that can be involved with these procedures. And BCI encompasses a large range of technologies. I can say that if we're talking about invasive BCI, the ones that go into the nervous system directly, those carry inherent risks that may not be worthwhile even for the able-bodied person, or puts them at risk of damaging something that is not having problems at the moment. So if you were young and you want a brain implant, and something goes wrong with the surgery, or there was a stroke at the time of the implant, that could be very debilitating and completely affected trajectory of the young person's life. Now, if the safety profile of these devices changes over time, so where that risk becomes minuscule, then that equation might change. That risk benefit might change. But at the current iteration of this technology, I think we're very far away from a routine simple intervention with no risk, which is where really that's when things would take off for everybody wanting access to it. Dana Taylor: What's on the horizon for you and your team? Dr. Iahn Cajigas: I mean, the technology is so exciting. So my main goal with our research is to really re-enable folks that have had paralysis from stroke or spinal cord injury to be able to move their limbs or move a proxy of their limbs, maybe it's a robotic arm and, or exoskeletons that allow them to walk. We've been working on decoding gestures of the hand, so fine finger movements of the hand to maybe allow folks to control a prosthetic limb if they're an amputee. I think that in the next five years, that's where my research team will spend the majority of time, is how do we take the signals from the brain related to movement, translate them into the actions that folks are wanting to do, and give them this ability to interact with their world. And at the moment, we're focusing on upper extremity function. Dana Taylor: Dr. Cajigas, thank you so much for being on The Excerpt. Dr. Iahn Cajigas: My pleasure. Thank you for having me, Dana. Dana Taylor: Thanks to our senior producers, Shannon Rae Green and Kaely Monahan for their production assistance, our executive producer is Laura Beatty. Let us know what you think of this episode by sending a note to podcasts@ Thanks for listening. I'm Dana Taylor-Wilson. We'll be back tomorrow morning with another episode of USA TODAY's The Excerpt.
USA Today
2 days ago
- USA Today
What is life? A little microbe raises big questions.
It's tiny and needy, but is it alive? That's a question prompted by recent research that highlights a surprisingly complex part of biology. The organism in question is a microbe called Sukunaarchaeum mirabile, discovered by researchers in Canada and Japan who were looking at the DNA of a species of marine plankton, according to a new paper published on bioRxiv. They've found it's unusually reliant on an alive host to survive, which could further blur the lines between cellular life and viruses — which generally considered to not be alive. The National Human Genome Research Institute describes viruses as existing "near the boundary between the living and the nonliving." Viruses can't function without interacting with a living cell. On their own, they're also essentially inert – unable to move – as a 2017 study notes. Enter Sukunaarchaeum mirabile, which could complicate things further. What is it? "This organism represents a totally new branch in the archaeal tree of life," lead researcher Takuro Nakayama of the University of Tsukuba told USA TODAY. (Archaea are microorganisms that define the limits of life on Earth.) "Sukunaarchaeum is not a virus, but a highly streamlined cellular organism," Nakayama said. According to the new study, which has yet to be peer-reviewed, "the discovery of Sukunaarchaeum pushes the conventional boundaries of cellular life and highlights the vast unexplored biological novelty within microbial interactions." Named for a Japanese deity Named for a Japanese deity known for its tiny size, Sukunaarchaeum has one of the smallest genomes ever recorded: "Its genome is drastically reduced – less than half the size of the previously smallest known archaeal genome," Nakayama said. The authors in the study write that "its genome is profoundly stripped-down, lacking virtually all recognizable metabolic pathways, and primarily encoding the machinery for its replicative core: DNA replication, transcription, and translation." "This suggests an unprecedented level of metabolic dependence on a host, a condition that challenges the functional distinctions between minimal cellular life and viruses,' the study says. 'The tip of the iceberg' "Sukunaarchaeum could be just the tip of the iceberg, pointing to a hidden diversity of life forms with ultra-reduced genomes within the so-called 'microbial dark matter,'" Nakayama told USA TODAY. Indeed, the discovery of Sukunaarchaeum's bizarrely viruslike way of living 'challenges the boundaries between cellular life and viruses,' Kate Adamala, a synthetic biologist at the University of Minnesota Twin Cities who was not involved in the work, told Science magazine. 'This organism might be a fascinating living fossil – an evolutionary waypoint that managed to hang on.' The study concludes that "further exploration of symbiotic systems may reveal even more extraordinary life forms, reshaping our understanding of cellular evolution." What does 'life' mean to scientists? "I am not an expert on the philosophical definition of 'life," Nakayama said, adding that the definition is not uniform among scientists and is a subject of continuous debate. "Many scientists would agree that cellular structure, the ability to replicate, and the ability to metabolize are key features of life. Viruses typically lack these features," he said. "The discovery of Sukunaarchaeum is interesting in this context because it lacks one of those key features: metabolism. The existence of a cellular organism that seemingly lacks its own metabolism provides a new and important perspective to the ongoing discussion about the definition and minimal requirements of life." Contributing: Joel Shannon, USA TODAY
