killer whales preying on sharks for the first time
[ad_1]
Killer whales have been filmed for the first time hunting and eating great white sharks. The unusual scenes were filmed by helicopter and drone pilots off the coast of South Africa, providing the first direct evidence that killer whales prey on sharks. Killer whales have attacked at least four sharks in about an hour, and this unusual predatory behavior may be spreading among this species.
In June of this year, a short video of the attack from a drone was published, and this month an article was published that analyzes the clip and all the footage taken from the helicopter. Scientists from the Academy of Marine Dynamics studied video recordings and analyzed data from a survey of unmanned aerial vehicles and submarines in cages before and after these events.
Lead author Alison Towner: “This behavior has never been observed in detail before – and certainly never from the air.”
Killer whales have also been known to prey on other large marine species such as blue whales, tiger sharks, and sevengill sharks.
New footage shows one of these killer whales, known locally as “Starboard”, eating what was thought to be a large piece of shark liver on the surface of the ocean.
Study co-author Dr. Simon Elven: “Orcas are highly intelligent and social animals. Their group hunting methods make them incredibly effective predators.”
White sharks were seen on every survey day in the weeks leading up to the attack, and several sharks were also seen on the day of the attack. However, 45 days after the attack, only one white shark was sighted, confirming that the sharks had left the Mossel Bay area.
Dr. Alison Kok, shark expert: “We first observed the reaction of sevengill and great white sharks to the presence of killer whales on the port and starboard sides in Falsh Bay in 2015 and 2017. The sharks eventually abandoned their former key habitats, which had a significant negative impact on both the ecosystem and tourism.”
The authors suggest that if more killer whales adopt the practice of hunting white sharks, then this behavior will have much wider consequences for their population. It is hoped that their findings will lead to the development of more effective strategies for the conservation of great white sharks. In just 50 years, the number of sharks in the open oceans has declined by more than 70 percent. Three-quarters of the species are threatened with extinction – including the Great White – due to factors such as climate change and overfishing.
Khristina Denisyuk
Photo: Discovery
[ad_2]
Source link
