Lstrblg

At sea, nobody can hear them swimming. Actually, this is very cool. A neat article on how orcas hunt in stealth mode at the Beeb.

Killer whales Orcas are one of my daughter’s many, many favorite animals. In fact, I don’t use “killer whales” anymore thanks to her goading.

Still, let’s not fool ourselves, they are apex predators and you, all fat and stuffed into a wet suit, are pretty much just an oddly rubber-tasting seal moments away from a bloodly, wet devourment*.

The researchers thought the predators might switch to very high frequency whistles to co-ordinate the hunt.
But the orcas actually go completely silent and are somehow still able to form organised hunting groups.

They used hydrophones – underwater microphones – to listen to and record orcas communicating with each other. The team could even hear crunching sounds when the animals were eating their prey.

Go ahead and listen at the article. Pretty awesome, actually.

File this under Things I Didn’t Know (and germane to the article’s point), but scientists believe that there may be two sub-species of orca. One “resident” species that primarily eat fish and a “transient” species that favor seal meat…mmmm…

Resident orcas hunt for salmon using echolocation. The orcas click, producing waves of sound that travel through the water and bounce off the fish, allowing the predator to sense its location.
“But all marine mammals have excellent underwater hearing,” explained Dr Deecke.
“If if a killer whale swam along clicking like mad, all the seals and porpoises would think – here comes a predators, let’s get away.”
But the transient orcas’ solution surprised the researchers.
“They go into stealth mode – completely silent,” said Dr Deecke. “This raises the question: how are they communicating?”
It seems that orcas can carry out complex, co-ordinated mammal-hunting trips without “talking to each other” at all.

That’s pretty sweet…but I’m still not going in the water with them

(Lastly, kudos for the BBC for linking to the source publication.)

*Turns out Devourment is a death metal band from Texas. No word on whether they sing about orcas.