How Realistic Is the Buzzy New Movie About Getting Swallowed by a Whale? A Whale Biologist Weighs In.

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In 2020, when author Daniel Kraus saw a viral video of a group of kayakers being “swallowed” by a humpback whale, he decided to find out if it was even scientifically possible. The answer? Sort of, in the right conditions and with the right kind of whale: a sperm whale, to be precise. His dedication to seeing how this traumatic encounter would hypothetically play out, and what it could come to represent in a larger story about the human condition, led to his 2023 survival thriller novel, Whalefall .

The book follows a teenager, Jay, who has a complicated, near abusive, relationship with his father, Mitt, a pillar of the local scuba-diving community. Jay ultimately estranges himself from his father, refusing to talk to him even after finding out that Mitt is dying from cancer. After Mitt kills himself by jumping off of a boat while wearing diving weights, Jay returns home to wrestle with his absence during Mitt’s final moments and to recover some of Mitt’s remains from the ocean. But, while diving in search of the remains, Jay is swallowed whole by a sperm whale. Armed with only his father’s training to help him, he must escape the belly of the beast before his tank runs out of oxygen.

This year has been big for Kraus. He won a Pulitzer for his most recent novel, and Whalefall has now premiered as a major motion picture, directed by Brian Duffield and starring Josh Brolin as Mitt and Austin Abrams ( who is also having a big year ) as a college-aged Jay. But, now that we can bask in all of Whalefall ’s impressive underwater glory, one question prevails: Just how realistic is it? To dive into the mysteries of Whalefall ’s deep, I spoke with certified sperm whale expert Shane Gero, biology lead at Project CETI .

Slate: I want to start off with some basic 101: What is the difference between a sperm whale and other types of whales?

Shane Gero : There are somewhere between 90 and 100 species of whales, dolphins, and porpoises in the world. The main divide is that there are those with teeth, like the sperm whale or the orca, and those with baleen—which is kind of like a comb made out of fingernail material—like the humpback whale. You picture a humpback whale or a blue whale, and they open their mouth wide and engulf huge amounts of water and then spit the water out, and all the fish or the krill or whatever stay in their mouth.

Now I want to break down how Whalefall ’s protagonist, Jay, actually winds up swallowed by the whale. Before he even sees the whale, he hears these clicking-like sounds. Are these accurate to the sounds a sperm whale makes?

When I first saw the trailer , I was actually kind of ecstatic because I think the whale looks fantastically realistic and quite beautiful, and the trailer uses real sperm whale sounds. They’ve added a bit of bass, I think, but, ultimately, yeah, the sperm whale has the most powerful natural biosonar system. They live in a part of the world’s oceans that is pretty much dark all the time. We think about them as divers, but really they’re surfacers.