The creature was enormous. Sailors said it “looked more like an island than a fish.” When feeding, according to a 13th-century Old Norse manuscript, the beast, known as the hafgufa, would rest with its mouth open wide, luring in unsuspecting fish, then snap its jaws shut to capture them. Hair-raising accounts of a similar sea monster were recorded by Alexandrian scribes as early as the second century A.D.; these accounts spread through Europe and Asia in Arabic, Coptic, Latin and Old English translations.
Now researchers argue the mighty hafgufa, and similar sea monsters described by the ancients, were not mythical creatures but rather whales engaged in a behavior that was only recently documented: “trap feeding.”
In 2011, marine biologists studying whales in the wild first observed “trap feeding,” in which whales—notably humpbacks—float motionless at the water’s surface with their mouths agape. The link to ancient legends was forged by John McCarthy, a marine archaeologist at Australia’s Flinders University, who became intrigued by the old local sagas—and the hafgufa—while excavating a shipwreck off the coast of Iceland. Working with medievalist colleagues at Flinders, McCarthy uncovered further instances in which ancient humans apparently observed the same sneaky feeding behavior—and attributed it to sea monsters. They argue these Greek and Norwegian bestiaries are evidence that this supposedly novel cetacean hunting strategy could be much older than marine biologists had known.
Some critics argue that these ancient accounts, with their fanciful illustrations, are too outlandish to be used as scientific evidence. Still, McCarthy and others contend that trap feeding could have been more commonly observed before industrial whaling nearly obliterated many whale populations, because back then, whales faced more competition for food and may have tried experimental hunting techniques—and because our ancestors simply came across whales more frequently. It’s estimated there were more than 100,000 North Atlantic humpbacks before the 17th century, but fewer than 1,000 by 1955. The ancients would have witnessed seas “really teeming with whales,” McCarthy notes, and thus were more likely to encounter the feeding behavior.
Now, with populations growing again thanks to conservation efforts—some scientists estimate North Atlantic humpbacks have rebounded 20-fold since 1955—the researchers argue whales may be returning to old habits described by our ancestors. Henry Huntington, a researcher for Ocean Conservancy, says the team’s argument is “strong” and particularly commends their methodology: “Taking old sources seriously is a welcome approach.”