DYK scientists played pilot whale calls to wild orcas, and the ocean's top predators sped away, and nobody knows why they fear a smaller whale?
Orcas are the ocean's apex predator, yet researchers off Iceland found they react to pilot whales much like they do to naval sonar. They tagged eight wild orcas and played them recordings of pilot whales. The orcas swam away at nearly double their usual speed (about 1.5 to 2.7 meters per second) and bunched into tighter, lined-up groups.
The relationship runs both ways. Pilot whales are drawn to orca sounds and have been seen approaching orcas at speed, often in large groups. Yet no pilot whale has ever been reported attacking an orca. The researchers say it remains unclear why the apex predator treats them as a threat, though larger pilot whale groups have triggered stronger reactions in past observations.
It was a small experiment, with 8 pilot whale playbacks, so the debate is open. Orcas also reacted much less to a control noise.