Mysterious whale feeding behavior only documented by scientists in the 2010s has been described in ancient texts about sea creatures as early as two millennia ago, new research suggests.
In 2011, Bryde’s whales in the Gulf of Thailand were first observed at the surface of the water with their jaws open at right angles, waiting for fish to swim into their mouths. Scientists named the unusual technique, then unknown to modern science, as “tread water feeding”. Around the same time, similar behavior was discovered in humpback whales off Canada’s Vancouver Island, which scientists called “trap feeding”.
In both behaviors, the whale positions itself vertically in the water, with only the tip of its snout and jaw producing from the surface. The key to the technique’s success, the researchers believe, is that the fish instinctively flock towards the apparent shelter of the whale’s mouth.
Researchers from Flinders University now believe they have identified several descriptions of the behavior in ancient texts, the earliest appearing in Physiologist – the Naturalist – a Greek manuscript compiled in Alexandria around 150-200 AD.
Dr. John McCarthy, a maritime archaeologist at Flinders University in Adelaide, South Australia, and the study’s lead author, made the discovery while reading Norse mythology, about a year after he had seen a video of a whale feeding.
He noted that accounts of a sea creature known as hafgufa seemed to describe the feeding behavior. “It was really a coincidence,” McCarthy said.
The most detailed description appeared in an Old Norse text from the middle of the 13th century known as King’s shadow watch – The king’s mirror. It reads: “When it goes to feed … the big fish keeps its mouth open for a while, no more or less wide than a great strait or fjord, and ignorant and careless, the fish rushes into its number. And when the stomach and mouth are full, the (hafgufa) closes its mouth, and thereby catches and hides all the prey that had come to seek food.”
The King’s Mirror was an educational text used to explain the world to young people, McCarthy said. “They exaggerate the size … (but) it’s not a fantastic description with any kind of supernatural elements.” He added that the distinction between fish and marine mammals may not have been well understood at the time.
A 1986 analysis by the King’s Mirror had found connections between 26 Old Norse descriptions and scientifically recognized marine animals, but had concluded that the hafgufa “must be relegated to the world of the miraculous”.
“The sea urchin was frustrating for these scholars because they couldn’t quite figure out any animal that matched it,” McCarthy said. “Now (with the newly documented feeding behavior) we think we have an explanation for it.”
In the Naturalist—a 2,000-year-old text that “preserves zoological information brought to Egypt from India and the Middle East by early natural historians such as Herodotus, Ctesias, Aristotle, and Plutarch”—the ancient Greeks referred to the creature as aspidochelone.
A surviving version of the text reads: “When it is hungry, it opens its mouth and breathes out from its mouth a certain kind of fragrant smell, which smell, when perceived by the smaller fishes, gathers in its mouth. . But when his mouth is filled with various small fish, he suddenly closes his mouth and swallows them.”
The researchers noted: “Definitive evidence for the origins of myths is extremely rare and often impossible, but the parallels here are far more striking and persistent than any previous suggestions.
“The lack of scientific observations before the last two decades can be explained by the relative rarity of this feeding strategy, or alternatively, because the strategy was not used.”
Dr Olaf Meynecke, a research fellow at Griffith University’s Coastal and Marine Research Centre, who was not involved in the research, said: “It is interesting that this type of feeding was documented thousands of years ago, but described as a new technique in recent years. . “
“It shows that such interesting feeding behavior has clearly captured the human imagination in the past.
“The trap feeding most likely only works in the presence of other predators,” Meynecke said, adding that it had been observed in individual whales and was not a social feeding activity.
“Since it (has a) low energy cost to the whale, this feeding activity makes the most sense when there are fewer schools of fish left over after a feeding frenzy.”
Bryde’s whale and humpback are both rorquals, a type of baleen whale.
The study was published in the journal Marine Mammal Science.