A mysterious population of killer whales, said to have hunted alongside native Australian whalers for millennia and European whalers for decades, appears to have disappeared, genetic analysis has revealed.
The coastal Thaua people, part of the Yuin nation, will sing to beowas (killer whales) as they have hunted beaked whales together for generations in Turembulerrer (Twice) Bay off eastern Australia. Killer whales took only the lips and tongues of killed whales in a mutually beneficial exchange called the “Law of the Tongue,” according to a study published Oct. 12 in Journal of Heredity.
In the 19th century, European colonizers took advantage of this law to establish a thriving commercial whaling industry in the bay. Written records suggest that killer whales would strike the waters outside the whaling station at Eden Township to alert whaling teams, which included Taua people, to the presence of whales. Orcas are said to have guided the whalers to the whales, sometimes by towing them on a rope, and manipulated the harpoon line to slow down the stranded whale and help secure the kill.
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By the 1930s, after being hunted by humans for 1,000 years, the population disappeared.
To learn more about these killer whales, the researchers analyzed the DNA of a 23-foot (7-meter) long killer whale (Orcinus orca) of this group called “Old Tom”. His DNA turned out to be different enough from living killer whales to suggest that the whaling population he belonged to was already extinct.
The study also used traditional knowledge to learn more about the relationship between Indigenous Australians and the ‘Eden killers’. Study co-author Steven Holmes, a Thaua traditional custodian, wrote in the study that the Thaua people consider the beowa (killer whales) to be their brothers, linked through Dreamtime stories that say when a member of the Thaua dies, they are reborn as a beowa.
“My people had a long friendship with the beow in Eden, especially Old Tom,” said Holmes. “My grandmother, Catherine Holmes, nee Brierley, told us of her great-grandfather, Budginbrough, who, along with other Taua, would swim with Old Tom holding on to his dorsal fin, my ancestors were never harmed or harmed.”
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Old Tom was washed up dead in 1930 and his skeleton is kept at the Eden Killer Whale Museum. Isabella Reeves, a PhD student at Flinders University in Australia, led the new study and went to the museum to drill old Tom’s teeth and jaw for DNA. They first established that Old Tom was a man. This is unusual for killer whales, given its active role in whaling, research has found male killer whales tend to let their mothers do the hunting. “Men are really lazy and they just like to look pretty,” Reeves said.
Old Tom probably shared a common ancestor with New Zealand killer whales. However, much of the variation in Old Tom’s genome is not present in the recorded DNA of any living population, meaning it was likely lost through extinction, the researchers found.
Most of the killer whales had left Eden by the time Old Tom died, and nearly all disappeared soon after. Thaua whalers originally hunted alongside killer whales for subsistence, but the method became commercial with Europeans. “By the time that relationship was commercialized, everything was going well,” Reeves said.
Exactly when and how the human-orc relationship began is unknown. Stories passed down from generation to generation suggest that the Taua people and other Aboriginal people hunted with killer whales long before Europeans began using them to aid in trading operations in the 19th century.
“We’re pretty confident it’s been going on for thousands of years,” Reeves said. “But how it started is another matter. I think what I’ve learned from killer whales is that they’re curious, they can be strategic, and when they want something, they know how to get it.”
some orca populations prey on baleen whales and feast with their tongues, but these killer whales tend to target whale calves. Reeves noted that the Eden orcas took down adults with the whalers, something they would have difficulty doing on their own.
Reeves said she wasn’t sure people would have believed the Eden orca story if it weren’t for the “mind-blowing” photographic evidence of the time. “To imagine that happening now seems almost impossible,” she said.