The blue whale is the largest animal to ever live on our planet. You might wonder how much such a large creature eats. Well, you are not alone.

Scientists recently carried out a study to find out how much blue whales eat in a day. Their findings were not surprising. They found the whales eat a lot. In just one day, blue whales living in the North Pacific Ocean can eat about 14.5 metric tons of krill (磷虾). That means blue whales eat around 1450 metric tons of food every year.

Matthew Savoca of Stanford University said, "It's an unimaginable amount of food." Savoca also described the blue whales' size as "unimaginable." Blue whales are larger than even the biggest dinosaurs. They can grow to 33 meters long and weigh about 181 metric tons. The animal can grow to about the size of a Boeing 737 airplane. Nick Pyenson was the co-writer of the study. He said the amount of food blue whales eat in a day is about the weight of "one fully-loaded school bus."

To measure the amount of food the whales ate and to study eating behaviors, the researchers used many devices. Electronic tag devices were attached to the animal's back. They also used cameras, microphones, a GPS locator device and an instrument that follows movement. They used drones (无人机) to estimate the size of a whale's mouth area and how much food it could eat at one time. And they used instruments that recorded sound waves to estimate the amount of food in the waters near the whales.

Because they eat so much, they also produce much more excrement, than scientists had thought. This provides important nutrients for ocean ecosystems. These nutrients help to form phytoplankton (浮游植物), which serve as the base of ocean food webs. Whale hunting during the 20th century caused sharp drops in whale populations. Pyenson added that supporting whale recovery may help repair "ecosystem functions lost in the past hundred years."