Killer whales are skilled and persistent hunters that even the largest marine mammals on Earth are not safe from. Off the South African coast, some killer whales have specialized in killing another dreaded predator of the water: they hunt great white sharks. A team led by Alison Towner from Rhodes University in South Africa was able to directly detect this behavior for the first time on two different occasions from a helicopter and with the help of a drone, as the working group reports in "Ecology".
One of the two shark hunts took place on May 16, 2022 in Mossel Bay. A hobby drone pilot had observed movements in the water via the camera and tracked down a group of orcas, which he then followed with his aircraft. A total of five killer whales had gathered in the area, two of which were heading to a well-known gathering place for sharks near the local estuary, while two more were apparently patrolling on the surface. Only a few seconds later, the fifth whale suddenly emerged from the depths between its four conspecifics and pushed a shark about three meters long to the surface.
The sword whale turned quickly after the appearance and then bite in the middle of the body: obviously to kill the shark. Then he dipped again, whereupon a second Orca packed the Haischwanz and pulled the entire body into the depths, whereupon the drone pilot no longer discovered him.
One of the killer whales was later identified as a "starboard": an individual who, along with a second animal named "Port", was previously suspected of regularly hunting sharks and eating their liver. This behavior can be seen on footage from a helicopter that was also traveling over Mossel Bay on the same day. The pilot watched and filmed with his smartphone how killer whales killed two more sharks. Most likely, this was the same group that was previously monitored by the drone.
"Starboard" also participated in this hunt. Scenes show how the whales follow the sharks and how they try to escape their hunters. The sharks try to swim as close as possible so that the larger marine mugs do not offer an opportunity to attack while keeping them in mind. However, since the whales often hunt together, it is not enough to only look in one direction, which is why the orcas usually make their prey.
Later, in a sequence, a killer whale can be seen eating a huge shark liver: this is very high in fat and floats upwards as soon as it has been torn from the predator's body. That is why the whales have their sights set on this energy-rich organ in particular: liverless shark bodies are regularly driven on South Africa's coasts.
According to eyewitnesses, there were at least ten sharks in the Mossel Bay in front of the attack. After that, hardly any predatory fish were observed there for weeks; They avoided the region. Since "Starboard" is probably hunting with other swords, this behavior could spread, the biologists suspect. For the sharks of the region and the associated diving tourism, this would not be good news.
