Not all humpback whales are alike. The humpback whales of Alaska have developed an ingenious way to catch herring: they use nets made of bubbles in a unique cooperative strategy.
As few as 100 whales have learned how to bubble-net cooperatively, and Southeast Alaska is the only place on earth where they do it.*
A pod of whales divides the fishing tasks into three distinct parts. "Herders" circle a shoal of herring to corral them into a ball. "Callers" dive beneath the herders and the herring to emit a piercing sonic siren of 180 decibels that stirs the herring into a frenzy and drives them towards the surface. Then the "ring leader" circles the herring while letting out a steady stream of bubbles, creating a barrier the herring will not cross. Now that the bubbles are trapping the shoal, which are still panicking to the surface, the whales enter the net from below and rise up like a many-headed sea monster to scoop the herring into their expanded throats.
It takes a lot of herring to fill a whale; herring look like rice grains compared with an adult humpback and the whales can eat over a ton a day. Bubble net feeding is like making "rice" into a sticky sushi rice ball rather than trying to catch individual grains.
*Other humpback whales, as well as other whales and dolphins, use bubble net techniques, but the Alaska humpback whales are the only ones that use this cooperative strategy.
One of the highlights of a Southeast Alaska yacht cruise is the flexibility to go where the whales are feeding to try to catch this breathtaking spectacle. First you hear the call, then you scan the waters for the tell-tale ring of bubbles. Get ready! Many tons of whale, mouths agape, are about to surge through the boiling surface. It's an unforgettable site.