Scientists Unravel Evolutionary Secrets of “Old Tom” and the Killer Whales of Eden

Evolutionary biologists have successfully unraveled the genetic lineage of a renowned killer whale in Australia for the first time.

For the first time, evolutionary biologists have unraveled the genetic history of a renowned killer whale and its group, which historically collaborated with whale hunters off the New South Wales coast.

The leader of this pod, known as Old Tom, famous for helping whalers in hunting baleen whales during the 20th century, has been found to have genetic connections to present-day killer whales in New Zealand according to new DNADNA, or deoxyribonucleic acid, is a molecule composed of two long strands of nucleotides that coil around each other to form a double helix. It is the hereditary material in humans and almost all other organisms that carries genetic instructions for development, functioning, growth, and reproduction. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>DNA research.

Old Tom also shared a common ancestor with killer whales from Australasia, the North Pacific, and North Atlantic Oceans, but is most similar to modern New Zealand killer whales. However, most of Tom’s DNA code is not found in other killer whales globally suggesting that the killer whales of Eden may have become extinct locally.

Graphic depicting ancestry testing of “Old Tom”, a killer whale central to a cooperative hunting relationship with human whalers. Credit: Isabella Reeves at Flinders University

Old Tom’s Unique History and Current Research Efforts

Known as the killers of Eden, Old Tom, and his family would help whalers hunt their target and were rewarded with the lips and tongues from the whale carcass. This is known as the “Law of the Tongue.”

This legendary relationship between the whalers and Old Tom’s family persisted and developed a strong bond across many generations of whalers. Measuring 6.7 meters in length and weighing six tonnes, Old Tom is now on display in the Eden Killer Whale Museum after washing up on shore in 1930.

DNA testing of Old Tom at the Eden Killer Whale Museum in Australia. Credit: Charlie White

Led by PhD Candidate Isabella Reeves at Flinders UniversityFounded in 1966, Flinders University is a public university in Adelaide, South Australia. It was named in honor of British navigator Matthew Flinders, who explored and surveyed the South Australian coastline in the early 19th century.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>Flinders University and the Cetacean Research Centre, alongside a global research team that undertook an ambitious journey relying on ancient DNA techniques to attempt to trace Old Tom’s genetic lineage through DNA sequencing and comparing his DNA with killer whales globally.

Through collaboration with Thaua Traditional Custodian Steven Holmes, the researchers have also revealed new insights in an attempt to decolonize the history of the Killers of Eden never officially documented before.

Map of Twofold Bay, NSW Australia. Credit: Isabella Reeves

Reeves’ Findings and the Indigenous Connection

Lead researcher Isabella Reeves says that while the genetic comparisons didn’t find any direct descendants of Old Tom, the researchers did find that Tom shared much of his DNA variation with other killer whales, suggesting they are locally extinct today.  

“The killers of Eden represent a rare partnership between people and whales. It was an exciting journey to trace the genetic ancestry of Old Tom, in order to provide the first insights into the genetic history of this group that captured the hearts of the community and whale lovers.”

“Our research also delved into uncharted territory by unveiling a decolonized history. We collaborated with a Traditional Custodian, which gave us a fresh perspective on Eden’s whaling history to rectify historical inaccuracies and shed light on a crucial aspect of this unique story about the bond between their people and these whales. Importantly, we want to ensure this aspect of the story is acknowledged moving forward.”

Ancient DNA lab work at Flinders University on Old Tom and the Killers of Eden. Credit: Andrew Foote

In Twofold Bay, the coastal Thaua people, part of the Yuin nation, had a connection with the killer whales through the Dreaming, a relationship that was highly respected and relied upon due to the Thaua’s dependency on the ocean for resources.

“It’s important that we recognize that Indigenous Australians initiated the relationship with the killer whales before European colonization and the advent of commercial whaling locally. This study rectifies discrepancies in local records and provides new insight into the origins of the killer whales in Eden and the history of Australasian killer whales,” says Ms Reeves.

Old Tom skeleton at the Eden Killer Whale Museum. Credit: Charlie White

Traditional Custodian, Steven Holmes, says the Thaua people had a long-lasting friendship with the whales in Eden, especially Old Tom.

“We consider beowas (killer whales) to be our brothers. Our Dreamtime stories which connect us to the beowas, is that when a Thaua member dies, they are reincarnated as a beowa. The beowas remained part of the Thaua, even after passing. The beowas would help the men by herding the other whales in the bay of Turembulerrer (Twofold Bay) for the whalers to kill. The Indigenous whalers would reward the beowas the tongue of the dead whale. This was soon known as the Law of the Tongue.”

Reference: “Ancestry testing of “Old Tom,” a killer whale central to mutualistic interactions with human whalers” by Isabella M Reeves, John A Totterdell, Emma L Betty, David M Donnelly, Angela George, Steven Holmes, Luciana Moller, Karen A Stockin, Rebecca Wellard, Charlie White and Andrew D Foote, 12 October 2023, Journal of Heredity.
DOI: 10.1093/jhered/esad058

The study was funded by the Royal Society of South Australia, the Playford Trust Foundation, the Australian Government, and the European Research Council.