How are or­cas able to hunt dol­phins and por­poises?

BBC Wildlife Magazine - - Q & A - Michael En­gel­hard

Highly so­cial, in­tel­li­gent or­cas or ‘wolves of the sea’ hunt large prey in pods. While only one species, or­cas oc­cur in two adap­ta­tions: no­madic ma­rine mam­mal hunters and more sta­tion­ary fish-eaters.

Sim­i­lar to the way they pur­sue seals, or­cas can breach and knock smaller, toothed whales out of the wa­ter to con­fuse and tire or stun them. And the pods of­ten split up in or­der to hunt in­di­vid­u­als. They will share a kill with their kin, re­ward­ing co-oper­a­tion.

It is pos­si­ble for a chase to go on for some time. In Prince Wil­liam Sound in the Gulf of Alaska, high-speed sur­face pur­suits of Dall’s por­poises, which in­volve orca aerial leaps, have lasted for up to 43 min­utes.

Few peo­ple ever wit­ness or­cas at­tack­ing por­poises and dol­phins. How­ever, in 2016, a cruise skip­per in Mon­terey Bay, Cal­i­for­nia, filmed eight to ten that had con­vened to chase grey whale calves but in­stead am­bushed a 1,000-strong com­mon dol­phin ‘su­per-pod’. An­tic­i­pat­ing the dol­phins’ course, the or­cas lay low, hid­ing un­der the sur­face be­fore charg­ing up­ward to hit their quarry.

Some or­cas spe­cialise in hunt­ing other cetaceans, and work as a pod to kill their quarry.

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