Abstract
Killer whales (Orcinus orca) have been documented to prey on white
sharks (Carcharodon carcharias), in some cases causing localised shark
displacement and triggering ecological cascades. Notably, a series of
such predation events have been reported from South Africa over the last
decade, with killer whales specifically targeting shark’s liver.
However, observations of these interactions are rare and knowledge of
their frequency across the world’s oceans remain limited. In October
2023, a 4.7 m (total length) white shark carcass washed ashore in
south-eastern Australia, coinciding with reports from citizen scientists
of killer whales hunting a large, unidentified prey item in the area.
Visual inspection of the carcass revealed that the liver, digestive and
reproductive organs were missing, and the presence of four distinctive
bite wounds, one of which was characteristic of killer whale liver
extraction as seen in South Africa. Genomic analyses performed on swabs
taken from the bite wounds confirmed the presence of killer whale DNA in
the major bite area, while the other bites were embedded with genetic
material from the scavenging broadnose sevengill shark (Notorynchus
cepedianus). These results provide confirmed evidence of killer whale
predation on white sharks in Australia, and the likely selective
consumption of the liver, suggesting predations of this nature are more
globally prevalent than currently assumed.