How Blue Whales Become and Remain So Big By Feeding on Tiny Krill

First Posted: Oct 05, 2015 07:45 AM EDT

How do blue whales become so big? Scientists have taken a closer look at the cetaceans and have found how these cetaceans maintain their enormous body size through foraging strategies that optimize the energy they gain from the krill they eat.

Large, filter-feeding whales are often thought of as indiscriminate grazers that swallow whatever tiny krill they come across throughout the day, regardless of how prey is distributed in the ocean. In order to see if that was the case, the researchers tagged blue whales, revealing sophisticated foraging behavior that targets the densest, highest-quality prey, maximizing their energy gain.

It's important to understand how blue whales feed. This will help inform officials of the protections needed for this endangered species. In addition, it will help inform people of their recovery needs.

"For blue whales, one of our main questions has been: How do they eat efficiently to support that massive body size," said Elliott Hazen, one of the researchers, in a news release. "Now we now that optimizing their feeding behavior is another specialization that makes the most of the food available."

Adult blue whales can grow to the length of a basketball court and weigh as much as 25 large elephants combined. However, they feed by engulfing as much prey-laden water as they weigh and then filtering out the krill it contains. However, dense krill patches can be deep and difficult to find.

In this latest study, the researchers found that when krill were spread out, or less dense, blue whales fed infrequently to conserve their oxygen and energy use for future dives. When krill became more dense, though, the whales fed more frequently.

The findings reveal that the whales don't feed indiscriminately. Instead, they carefully target their feeding for the best quality food.

The findings are published in the journal Science Advances.

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TagsWhale, Whales, Blue Whale, Feed, Conservation, Krill, Biological Conservation, Endangered species, Prey