Humpback Whales Disrupt 115 Orca Hunts, Often Shielding Other Species

3 articles · Updated · spacedaily.com · Aug 24

A 2017 review logged 115 cases from 1951 to 2012 in which humpback whales interfered with killer whale attacks, including a documented 2009 rescue of a Weddell seal in Antarctica.
In 57% of encounters, humpbacks initiated the contact, and 95% involved mammal-eating orcas, suggesting the whales selectively respond to hunts on warm-blooded prey rather than fish-feeding killer whales.
Only 11% of the interventions protected another humpback; the other 89% involved prey such as seals, sea lions, porpoises, grey whale calves, minke whales and even a sunfish.
Researchers say the behavior may stem from an evolved rule to break up orca attacks—originally to defend humpback calves—though some coordinated cases, including 14 humpbacks converging in Monterey Bay, are harder to explain.
The paper stopped short of calling the behavior true altruism, but said interspecific altruism could not be ruled out after six decades of observations.