Photo: wsweet321 (flickr)
We humans have many ways to catch fish. From simple poles to vast fishing nets, you might imagine we’ve cornered the market on fishing tools and strategies. Not so. On today’s Moment of Science we’ll learn how the humpback whale uses strategy–and even its own kind of net–to hunt fishy prey.
The mainstay of a humpback’s diet is a small, shrimp-like creature. To eat these, all a whale has to do is open its mouth and swim through a thick concentration of them. This method, called “lunge feeding,” works well for slow-moving prey, but what if the whale gets a taste for herring, or some other fish with enough presence of mind to swim to the side of a lunging whale? This is where the net comes in.
A humpback doesn’t weave its net from rope, but from air bubbles instead. Called “bubble-net feeding,” this method involves blowing bubbles in a tight, spiralling pattern underneath a school of fish. The rising bubbles surround the fish in a tube-shaped corral. When the tube is complete, the whale swims straight up, through its center. With bubbles to all sides and a hungry whale below, the confused fish try to escape by swimming upwards too.
Imagine yourself in a nearby boat: You’d see a circle of bubbles form on the water’s surface, then the sudden flash as scores of herring break the surface. Before they can fall back, the huge whale lifts out of the water beneath them, snaps its jaws shut, then crashes back into the ocean to digest its meal. Hundreds of fish in a single catch: Whales must tell good fishing stories!