As the largest animal on Earth, it is no surprise that the blue whale has a large appetite. However, the strategies behind the whale’s meal planning and survival methods to consume enough food have stumped scientists – until now.
According to CBC News, a new study shows that blue whales are not indiscriminate grazers as scientists have long believed. The blue whales, rather than arbitrarily swim around and eat whatever crosses their path, actually have a plan to how they feed.
The study, conducted of California’s coast, used tags on more than 50 whales –applied via suction cups — to track the movements of blue whales and their prey, small shrimp-like crustaceans known as krill. The blue whales tend to feed more intensely when the krill are high in numbers, but refrain from feeding when there are less krill. It is believed the blue whales do this to save oxygen for future dives.
The blue whales strategy behind their feedings conserve oxygen when prey is low in the area, and the animals switch to an “intense foraging at the expense of oxygen when prey quality is high,” said Elliot Hazen, research ecologist of the U.S. National Oceanic and Atmospheric Administration’s Fisheries Science Center and the University of California Santa Cruz.
We found that blue whales have a complex strategy of switching from conserving oxygen when prey quality is low, to intense foraging at the expense of oxygen when prey quality is high.
The whales are maximizing their energy in a way that scientists were unaware of before now, and “actively assessing their environment and taking advantage of prey,” said Ari Friedlaender, ecologist of Oregon State University’s Marine Mammal Institute.
The whales are much more actively assessing their environment and taking advantage of prey in ways that were unknown before, to maximize energy gain.
Blue whales are what is referred to as “filter-feeders.” The whales actually clean the ocean as they feed, using plates in their mouths made of keratin to strain krill from the sea.
When feeding, the whale opens its mouth while accelerating, and takes in a volume of water up to 130 percent of its weight. The water, full of their prey, is then filtered through a system where the whale’s throat distends, and using the muscles of the throat and its tongue, the whale forces water of its mouth through baleen plates that act as a sieve. The whale pushes the water back into the ocean, and the krill are left behind in the whale’s mouth for consumption.
Blue whales eat up to four tons of krill each day.