Imagine this: A giant sperm whale (Physeter macrocephalus) has just swallowed you whole. It might seem like a bizarre scenario to envision, but you’d hardly be the first. In the Bible’s Book of Jonah, the belly of a whale is the setting for the prophet Jonah’s  three days of repentance an d prayer. In the 1940 Disney film Pinocchio, Geppetto manages to rig up a cozy living space inside the stomach of Monstro the sperm whale, complete with amenities including  a small fire and a fishing setup for seafood that drifts in. Even his pet goldfish, Cleo, is swimming inside the microcosm of her highly ironic fishbowl. Surviving inside of a giant sea creature has become a classic “fish tale” of human resilience and redemption. In the latest reimagining of this theme, the upcoming movie Whalefall, a scuba diver is swallowed by a sperm whale and has exactly one hour to escape before his oxygen runs out. But for all our fascination with extended whale-squatting, one fact remains: it has never actually happened. The few close calls with whale ingestion have involved humpback whales, a species physically incapable of swallowing a person. In all cases, the whale spat the person up as quickly as you might cough up a bug that flew into your mouth. “I wouldn’t call that swallowed,” Shane Gero, a whale biologist and Lead Biologist at Project CETI, tells Popular Science. “I would call that a mistake by both the mammals involved.” So, if it’s never actually happened, is it even possible? A highly unlikely accident  Whalefall is the film adaptation of a 2023 novel of the same name by Pulitzer Prize winning author Daniel Kraus, and arrives in theaters on October 16.Protagonist Jay Gardiner is on a diving expedition to find the remains of his late father, a mariner who died at sea. Suddenly, Jay is swallowed by a giant sperm whale, with only an hour of oxygen remaining in his scuba tank. To try and survive, Jay deploys a series of highly resourceful, increasingly MacGyver-esque maneuvers, including using the beak of a squid to cut through the whale’s stomach lining, and navigating his climb up into the whale’s throat using the glow of a jellyfish.  The ordeal is an adrenaline-fueled adventure for Jay, but could any of it ever happen? Gero, who has studied sperm whales for over 20 years, thinks it’s highly improbable, starting with the swallowing part. “To my knowledge, no one has ever been eaten by a sperm whale,” he says.Gero hypothesizes that after some generous suspension of disbelief about sperm whales’ feeding habits and anatomy, there could be a situation where “the largest sperm whale ever” could accidentally ingest a human. Austin Abrams as Jay Gardiner in 20th Century Studios’ WHALEFALL. Image: © 2026 20th Century Studios. All Rights Reserved. “I think anatomically, maybe you could shove a slender human down the throat of a very large, male sperm whale,” he says. “Would it happen? Very unlikely. Certainly not with scuba gear and a scuba tank making the human that much bigger.” Yet Gero, who has read the novel, praised the book’s meticulous efforts to make the science line up, including its explanation for why a sperm whale would be anywhere near a scuba diver. Sperm whales usually feed at about 3,000-feet-deep at the bottom of the ocean, an area not typically occupied by scuba divers. The book reconciles this by having a giant squid (Architeuthis dux) struggling at the surface to escape being eaten by the sperm whale. When the whale comes to the surface to eat the squid, the squid latches onto Jay, who is then pulled into the whale’s mouth. But even after accepting this explanation, Gero notes that sperm whales use echolocation, which would likely distinguish a human as unusual prey, not a potentially tasty morsel. “Eating a human by accident seems very unlikely, but it makes for a really exciting story,” Gero says. The odds of surviving inside a whale If a person somehow managed to survive entering the mouth of a sperm whale without drowning from the propulsive rush of water, Gero says that their luck would worsen almost immediately. “More than likely, the human drowns the second they get smashed into the mouth of the whale, whether they were drawn in by a squid or accidentally brought into the mouth of a whale,” he says. “My guess is the person dies the second they enter the mouth.” Gero raises another interesting possibility. Sperm whales usually prey on boneless squid, so consuming a scuba-outfitted human could be a choking hazard, and could choke to death.  Male sperm whale swimming at the surface, Pelagos Sanctuary, Mediterranean Sea, Italy. Image: by wildestanimal via Getty Images. This would certainly make for a shorter movie, but Gero notes that the whale’s body could also have a more lively response to an unwanted foreign object in its mouth. “When I swallow something that I shouldn’t have, it’s like a non-controllable response — your body just starts moving its mouth and coughing,” Gero says. “In that sort of movement, or freakout, it probably is going to do a lot of physical damage to the human.” Although Gero acknowledges that he is not a  whale anatomist, he still believes that it would be highly unlikely for any living creature to make it into the stomach of a sperm whale, let alone set up camp there. “There are acids and gases,” he says. “The digestive tract of any mammal is not meant to be a livable place for any prey that ends up there.” Dr. Joy Reidenberg, a comparative anatomist at the Icahn School of Medicine at Mount Sinai in New York City who consulted on the anatomy for both the Whalefall book and film, explains that a sperm whale’s stomach is divided into four chambers. These chambers are a vestige from their early days as a land-based, plant-eating mammal about 50 million years ago. The first chamber is lined with thick, muscular tissue. It’s responsible for mashing up food, since sperm whales’ teeth, found only on the lower jaw, are too pointed to chew. If Jay needed something solid to grab onto and pull himself toward the whale’s throat, Reidenberg tells Popular Science he wouldn’t find much. It would mostly be “wet, slimy, squishy walls,” with “no hooks, no handles.” The one exception is the whale’s voice box, or larynx, which sticks up like a rigid pipe.  “If he gets his arm around that, he can pull himself out,” she explains. Even in that situation, Reidenberg says, few people would live to tell this phenomenal tale. “Most people, unless they have protection and air, couldn’t survive this situation. Also, a sperm whale would probably never swallow a person.” Meet your actual nightmare  While the  fictitious scenario of a massive sperm whale swallowing a human relies as much on poetic license as it does grounded science, could any other land or sea animal engulf an entire human being? Horrifyingly, yes. The reticulated python (Malayopython reticulatus), which is the world’s longest snake species and can measure as much as  26-feet-long, has been known to take in an entire human. According to a 2025 study tracking python-related deaths in Indonesia, 17 people were preyed upon by reticulated pythons between 1927 and 2025. Astonishingly, four of these people survived, although it’s unlikely they spent any quality time inside the snake. In several of the fatal cases, the humans were swallowed whole. Gero notes that a green anaconda (Eunectes murinus) might also be up to the task, since they can swallow animals as large as deer. Even then, this prey is already dead when it’s consumed. “Anacondas famously wrap around and crush their prey,” Gero says. “The body is limp by the time it goes down.” Austin Abrams as Jay Gardiner in 20th Century Studios’ WHALEFALL. Image: © 2026 20th Century Studios. All Rights Reserved. Why these fish tales endure Gero also makes one key distinction about sperm whales: they have absolutely no interest in preying on humans, intentionally or otherwise. In fact, humans have spent centuries slaughtering whales for oil, an uneasy relationship that may be part of why they loom so large in our storytelling. “If those stories exist from the whaling days, they’re more a lesson to future whalers than they are based in reality,” he says. “I’ve never seen any kind of aggression from a sperm whale. These are gentle giants of the deep.” Gero hopes movies like Whalefall will spark genuine curiosity about the intelligent, peaceful animals behind the myth. He and the team at Project CETI are working to decipher how sperm whales communicate with each other. In the meantime, you can visit listen.projectceti.org to record what you’d say to a sperm whale, if you ever had a chance.  This story is part of Popular Science’s Ask Us Anything series, where we answer your most outlandish, mind-burning questions, from the ordinary to the off-the-wall. Have something you’ve always wanted to know? Ask us. Related Stories The ‘Waymo of the sea’ tracks sperm whale conversations Baleen whales have an ‘oral plug’ to help them guzzle down food without choking Would my dog or cat really eat me if I died alone? Great whites don’t hunt humans—they just have blind spots The post Could a whale really swallow a human? We asked a biologist. appeared first on Popular Science. ...read more read less