The carcass was found on the beach at Cape Bridgewater near Portland.Portland Bait and TackleTheres no doubt about it: killer whales (Orcinus orca) are formidable predators. They feed on a diverse range of prey, from marine mammals like seals and whales to fish and even reptiles. However, they are also known to specialize in specific prey, such as whale tongue or shark liver, indicating a complex and regionally varied diet. Recent research has shed light on killer whale predation on white sharks, particularly in areas like South Africa and, more recently, Australia. This predation has caused significant shifts in the local ecosystems, as the killer whales targeting of specific shark tissues, like the liver, has led to the displacement of white sharks from certain areas.Famously, killer whales have been documented at length targeting white sharks in South Africa, resulting in a mass exodus of sharks from the area and triggering ecological cascades. These events have similarly been observed in California, although direct sightings of the predation are rare, making the phenomenon harder to study. In Australia, killer whales have been reported preying on various shark species, including blue sharks, porbeagles, and tiger sharks. But of particular interest to PhD student Isabella Reeves are the interactions between killer whales and white sharks. Several reports suggest that these apex predators are increasingly targeting white sharks in Australia for their liver, a highly nutritious part of the sharks body; an oil slick was observed following a suspected predation in 2015 in the Neptune Islands Group Marine Park (South Australia) but the carcass was never recovered for confirmation.On October 15, 2023, a group of killer whales was sighted near Bridgewater Bay, a known movement corridor for both killer whales and white sharks. Witnesses reported seeing cataloged killer whales Ripple and Bent Tip engaged in hunting behavior, corralling and tossing a large prey item which was speculated to be a large shark or small whale. Just two days later, a large white shark carcass washed ashore, sparking public interest due to its size and the bite marks it bore. State fisheries officers secured the carcass for investigation. And in came Reeves and other researchers, who utilized both wildlife forensics and citizen science data to provide the first confirmed evidence of killer whale predation on white sharks in Australia.While they are known to target great white sharks in some areas, these interactions don't occur ... ... [+] [+]Getty ImagesThe shark's body was found with large bite wounds on the pectoral girdle, consistent with previous reports of killer whale predation on white sharks. The pattern of the wound suggested a method of attack designed to access the sharks liver, similar to observations from South Africa. To confirm the identity of the predator, researchers collected DNA from the bite wounds and conducted genetic analysis. The results showed that the DNA from the large bite wound matched killer whale sequences, confirming that killer whales were responsible for the sharks death. Further investigation also revealed DNA from broadnose sevengill sharks (Notorynchus cepedianus) in other bite wounds, suggesting other animals took advantage of this free meal for some post-kill scavenging.MORE FOR YOUThis breakthrough study highlights the growing trend of killer whale predation on white sharks worldwide, suggesting that these interactions may be more common than previously thought. And while it answers a few mysteries of what happened that fateful day off the Australian coast, it also raises questions about the broader implications of killer whale predation on marine ecosystems. The removal of white sharks from an area can have far-reaching effects, as these apex predators play an essential role in maintaining the balance of marine food webs. By targeting specific prey, killer whales may be reshaping predator-prey dynamics in ways that are still not fully understood especially in an area that is famous for white sharks, like South Africa once was. Could what happened there happen Down Under? Thats a question that warrants further exploration.