Great white sharks are scared of orca - study

Great white sharks appear to be scared of orcas, which is good news for elephant seals.
Great white sharks appear to be scared of orcas, which is good news for elephant seals. Photo credit: Reuters

Great white sharks may not be the most formidable predators in the ocean after all.

A new study has found the hunter becomes the hunted when orcas show up.

And the sharks are so scared of the orcas they leave the feeding ground until the next season - even if the intruders don't stay long.

"When confronted by orcas, white sharks will immediately vacate their preferred hunting ground and will not return for up to a year, even though the orcas are only passing through," said Salvador Jorgensen, Monterey Bay Aquarium senior research scientist and lead author of the study.

The research team documented four separate encounters between the two species of apex predator in the Greater Farallones National Marine Sanctuary, off San Francisco, California.

Every time the orcas showed up, the great white sharks fled - and didn't return until the following season.

"We don't typically think about how fear and risk aversion might play a role in shaping where large predators hunt and how that influences ocean ecosystems," Dr Jorgensen said. "It turns out these risk effects are very strong even for large predators like white sharks - strong enough to redirect their hunting activity to less preferred but safer areas."

It's good news for elephant seals, the common prey of both sharks and orcas, who normally have to face both sets of predators in the Farallones.

But the orcas are more transitory, so the young seals have a better chance of survival with the orcas coming and going than if they didn't.

The study was published in Scientific Reports on Tuesday.