Astonishing observations: Orca group kills largest fish in the world
From Doreen Garud
La Paz (Bolivia) - Tuna, seals and turtles are regularly on the menu of orcas, but the whales can kill much larger prey.
A group of killer whales has been observed off the coast of Mexico targeting the world's largest fish: whale sharks. In a study published in the journal "Frontiers in Marine Science", researchers describe such attacks in detail for the first time.
"We describe a cooperative hunting technique on whale sharks in which the orcas specifically attacked the belly, causing the whale shark to bleed out and giving the orcas access to the fat-rich liver," said marine biologist Erick Higuera Rivas, one of the authors of the study. The orca group may have specialized in hunting whale sharks.
Whale sharks (Rhincodon typus), which belong to the shark family, can grow up to 20 meters long and weigh 34 tons. According to the environmental foundation WWF, their skin is probably the thickest of all living creatures at up to 15 centimetres.
They live solitary lives and can live up to 100 years.
Orcas work together strategically
Younger and therefore smaller whale sharks can often be found off the coast of Mexico. There, the three to seven-metre-long sharks are apparently sometimes prey for orcas (Orcinus orca).
The researchers investigated four attacks between 2018 and 2024 in different areas of the Gulf of California.
Using dorsal fins and scars, they were able to identify individual animals. They found that one particular orca, named after the Aztec ruler Moctezuma, was involved in three of the four attacks.
"When hunting, all members of the group work together and strike at the whale shark to turn it over," explained Higuera Rivas. In this position, the whale sharks become immobile and can no longer flee. This makes it possible for the orcas to reach the belly. As there are fewer muscles and cartilage on the belly, the area is less protected. This allows the hunters to reach the organs.
It is very impressive how strategically the orcas work together, said the researcher. "This shows what great predators they are."