Great white sharks are apex predators among their community's dreaded sea creatures. However, they share the same title with killer whales that hunt them.
Killer Whales Behind Dead Great White Shark
Officials suspected foul play right away when a dead, great white shark washed up on an Australian beach in October. One of the ocean's most feared predators, the shark, showed an unexpected twist when its stomach was ripped open.
Scientists have now established that a killer whale, or more likely, a pod of orcas, killed the enormous predator. Dr. Adam Miller of Deakin University reported this week that DNA traces from killer whales were found when the bite wounds were swabbed.
"We effectively took genetic samples, a swab of the bite wounds," Miller, associate professor of aquatic ecology and biodiversity, told ABC Radio Melbourne. "We were able to confirm that those bite wounds were just loaded with killer whale DNA. So it's a bit of a smoking gun."
The concerned shark had a length of over 16 feet. Considering that the great whites can reach a maximum length of 20 feet and 4,400 pounds, the dead shark is enormous. However, orcas, which may grow to 20 to 26 feet long and weigh over 13,000 pounds, are even larger than great white sharks.
The mutilated remains were discovered washed up on the shore in Victoria, across Port Phillip from Melbourne, in Bridgewater Bay.
Killer whales and great whites are both apex predators. However, the former are aggressively hunting the latter.
A previous study discovered a scarred 11-foot great white shark. It has a huge scar across its body. The researchers later learned that the mark was from an epic battle against two serial killer orcas. Per Alessandro De Maddalena, a former adjunct professor of marine vertebrate zoology at the University of Milano-Bicocca in Italy and the study's lead author, orca predation on great whites outside of South Africa has been documented.
Why Orcas Target Great White Sharks?
Several gruesome attacks made by orcas against great whites have been recorded recently. Earlier this year, two orcas made headlines after they went on a killing spree.
In February, two orcas - Port and Starboard - killed 17 sharks in a single day in South Africa. Since 2015, the Marine Dynamics Academy has tracked both killer whales to learn more about their foraging patterns.
Every shark that was discovered lacked a liver. Experts were certain that the great white's liver, which is abundant in squalene, a precursor to hormone production, was why Port and Starboard feasted on them.
However, the duo attacked with surgical precision, not by pulling out the livers. It is said that the killer whale pair collaborates. They drive sharks toward the surface, turn over their abdomens, and then bite into the stomachs of the animals to remove the oil-rich liver while sparing the other organs.
Since killer whales hunt sharks, which are apex predators, the lack of sharks affects ecosystems. According to a prior statement by Alison Towner, a white shark researcher who works with Port and Starboard, great white sharks have been staying away from the area to prevent orca attacks.
But marine ecosystems require balance, and in the absence of great white sharks, they can prey on seals and the critically endangered African penguins.
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