These Mythical Sea Monsters May Have Been Whales With Unusual Dining Habits

Tales of creatures like the Norse “hafgufa” suggest ancient and medieval people may have seen whales trap feeding

Trap feeding
A digital reconstruction of a humpback whale trap feeding, a behavior with striking similarities to the feeding habits of the "hafgufa" described in medieval Norse texts. John McCarthy, Flinders University

According to 13th-century Norse texts, when the great fish “hafgufa goes to feed, it belches some food, then stretches its massive mouth wide. The sea monster remains still, mouth agape, as fish come to nibble on the food, not knowing that they rest in the jaws of the behemoth. When enough unsuspecting prey have made this fatal mistake, the hafgufa snaps its jaws closed, enjoying the meal it has trapped.

John McCarthy, a maritime archaeologist at Flinders University, was reading a description of this mythical monster when it occurred to him that this feeding method—and a similar one employed by an ancient Greek beast called “aspidochelone”—resembled those of certain whales. At first, he thought it was just an interesting coincidence, but it soon became evident that this similarity could be something more.

“Once I started looking into it in detail and discussing it with colleagues who specialize in medieval literature, we realized that the oldest versions of these myths do not describe sea monsters at all, but are explicit in describing a type of whale,” McCarthy says in a statement. “The more we investigated it, the more interesting the connections became and the marine biologists we spoke to found the idea fascinating.”

In a paper published Tuesday in Marine Mammal Science, McCarthy and his colleagues present the striking similarities between ancient descriptions of the hafgufa and modern observations of whales.

In 2011, researchers noticed humpback whales leaving their jaws open at a right angle and waiting for food to come to them. This practice, known as trap feeding, has been seen at least a dozen more times since, but scientists thought it was a new behavior.

“It is interesting that this type of feeding was documented thousands of years ago but described as a new technique in recent years,” Olaf Meynecke, a marine researcher at Griffith University who was not involved in the research, tells the Guardian’s Donna Lu. “It shows that such interesting feeding behavior has clearly captured humans’ imagination in the past.”

Indeed, rather than evolving the strategy recently, it appears that whales may have been eating like this since more than 2,000 years ago, when the first known reference to “aspidochelone” appeared in a Greek manuscript. In addition to ancient and medieval texts, researchers also found 17th and 18th century texts that described the hafgufa—but with more flair than their Norse predecessors.

“Everybody assumed that it was so fantastical, it just couldn’t possibly be real,” Erin Sebo, an expert in historic manuscripts at Flinders University and a co-author of the new research, says to the Australian Broadcasting Corporation’s Genelle Weule. “It is really interesting that ancient and medieval people were seeing enough whales and getting close enough to whales to actually be able to observe this behavior as accurately as they did when modern people haven’t.”

Why scientists didn’t observe trap feeding until just over a decade ago remains a mystery. Perhaps modern technologies like drones have prompted discoveries by allowing scientists to watch whales more easily, McCarthy tells Sascha Pare of Live Science. Or, hunting could be to blame: “Whale populations are just beginning to recover toward their natural, pre-whaling size, and their behavior is changing as their numbers go up,” he tells the publication.

Though it is unlikely researchers can prove the hafgufa was, in fact, a trap feeding whale, the team says this new realization of parallels between the two creatures highlights the potential for new ways to understand the ancient oceans. It’s also a reminder, they say, that even though ancient people didn’t have the same scientific knowledge we have today, their observations could be more accurate than we realize.

“It can be easy to forget that people in the medieval past were just as discerning as we are today,” Lauren Poyer, an expert in Scandinavian history and culture assistant at the University of Washington who was not involved in the study, tells Jocelyn Solis-Moreira of Popular Science. “Their cultural knowledge and traditions were just as rich, and potentially even more valuable, than our knowledge today when it comes to surviving and thriving in their unique landscapes.”

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