Blue whales, or Balaenoptera musculus, are known to be the largest creatures on this planet. They have the ability to grow to be the length of a football field. The average weight of a blue whale is about 180 tons, and their median length is about 89 feet long. They have a big weight in their chest, as their heart by itself weighs around 400 pounds. One can’t help but wonder, how were they able to become so massive and continuously stay that way?
They eat, and eat, and eat some more
This is especially confusing, because they are known to feed primarily on the crustaceans known as krill, and since scientists thought these whales to be considered grazers, it would be hard to maintain their massive size while simply floating and filtering krill. They take in water and krill, which equates to about 130% of their body weight. They then, with the help of their plated teeth, let the water out, and manage to keep the krill that they will end up consuming. They eat about 40 million krill a day, but it still takes a large amount of energy to keep this cycle going. Because of this, researchers decided to take a closer look at what the whales were actually doing while looking for food. Are they really just grazing?
The Study
What was found was extremely interesting, and different from what was originally thought. The U.S. National Oceanic and Atmospheric Administration (NOAA) along with the Marine Mammal Institute originally thought that the whales were simply swimming without any strategy, so they decided to track their movements. They used digital recording archival tags to do this, which helped them compare all of their behaviors and patterns. They then combined this data with the density of the krill in the ocean. Once they did this, they saw that these whales were more hunters than grazers. They assess the area that they are in, and if the krill count is low, they avoid using the oxygen to conserve energy. When the krill count is high however, they consume all they can to make sure they are able to create as much, if not more, energy that they are exerting by lunging after these crustaceans.
