A pod of humpback whales is feeding in Lynn Canal in Southeast Alaska. These whales fast during winter months when they migrate to warmer tropical waters to breed and give birth to their calves, but they feed heavily in the summer months they spend in Alaska.
Biologists have learned that baleen whales such as humpback, blue, fin, and minke whales consume about three times more each year than previous estimates suggested. Researchers found that a blue whale in the North Pacific, for example, eats about 16 tons of food a day. That's about 35 million calories.
Biologists have long known what baleen whales eat by looking at the stomach contents of dead whales - but they were able to only estimate how much they ate. Researcher Matthew Savoca at Stanford University approached this question using underwater devices that measure the size and density of swarms of shrimp-like krill-a key food for many baleen whales. He and his colleagues also collected data from about 300 whales equipped with special tracking devices that monitored feeding behavior; and they measured how much water whales ingest when lunging through schools of food. The combined data indicates whales like humpbacks feed more often and eat more when they are feeding than previously thought.