By Jonny Lupsha, Wondrium Staff Writer
Bowhead whales can weigh as much as 200,000 pounds and stretch over 60 feet long. Animals as large as these have equally large appetites and a serious need to feed. What do whales eat and how do they go about doing it?
When we think of the great hunter species of the world—wolves, lions, great white sharks—we rarely put whales of any kind at the top of the list. Even the popular killer whales are actually a dolphin species. Yet, humpbacks get as heavy as 80,000 pounds, and that’s not from eating seaweed. In fact, humpbacks, a large species of baleen whale, are mostly carnivorous.
A recently observed feeding behavior in whales showed the giant marine creatures swimming to the surface with their jaws open, catching their prey from underneath. It may even explain some so-called “sea monsters” from ancient Norse mythology. However, this isn’t the typical behavior humans have long seen in whales.
In the video series National Geographic Polar Explorations, journalist Fen Montaigne discusses the feeding habits of several whale and other marine mammal species, including beluga and killer whales.
What Do Whales Eat?
Although killer whales, or orcas, are a dolphin species, they’re often associated with whales. According to Montaigne, orcas in the Antarctic eat seals and minke whales. In other parts of the world, orcas may eat schooling fish, sea lions, stingrays, sharks, and even other dolphins.
“The most commonly seen large whale in Antarctic waters is the humpback, which can grow to be more than 50 feet long and weigh up to 80,000 pounds,” Montaigne said. “Humpbacks are found in all the world’s oceans; their number is estimated at about 100,000 individuals, or slightly more. Several thousand humpbacks regularly migrate to the Southern Ocean every summer, primarily to feed on the vast quantities of Antarctic krill.”
Krill are small shrimp-like crustaceans. Humpbacks also eat other small fish besides krill, as well.
What about beluga whales? Due to their much smaller size, Montaigne said that belugas find shelter from predators in rivers and estuaries and that they’ve been spotted hundreds of miles upriver hunting for Pacific salmon, one of their favorite foods. Meanwhile, narwhals prefer to eat cod and halibut, diving as deep as a mile underwater to find them.
How Do Whales Eat?
Looking back over this eclectic list of marine mammals dietary preferences, it’s no surprise that their methods of catching food are equally diverse. According to Montaigne, killer whale researchers Robert Pitman and John Durban have seen orcas that will roam open waters to hunt, scour near the sea floor, or maneuver in and out of pack ice to find food.
“Pitman and Durban have observed certain Antarctic killer whales [making] a meal out of a Weddell seal using what’s known as the wave-washing technique,” he said. “This is a well-coordinated assault in which a handful of killer whales charges in parallel toward a seal on an ice floe, their tails moving in unison like synchronized swimmers.
“Then, just as they are about to hit the floe, the whales dive under it and they create a three-foot wave that […] washes the seal off the floe into the mouths of the waiting whales.”
Humpbacks also work together to eat. They often engage in “bubble-net feeding,” swimming in ever-tightening circles to confuse and crowd their prey. When the circles are small enough, a humpback will swim through the population of prey with its mouth open, catching its food while filtering out the sea water through baleen plates.
Belugas have large forehead lobes, called melons, that house their natural echolocation equipment. Among other things, the melons help the belugas locate food.
“Swimming in pods of up to 100 individuals, narwhals often follow cracks, or leads, through the frozen sea,” Montaigne said. “Using electronic tags, scientists have tracked narwhal diving almost a mile deep for cod and halibut. After completing such feeding dives, narwhal may surface and be unable to find a lead in the pack ice, causing them to drown.”
National Geographic Polar Explorations is now available to stream on Wondrium.