For the first time, the heart rate of a blue whale was measured while it was looking for food

Using an electrocardiograph attached to the body of a blue whale, scientists have for the first time in history measured the heart rate of a blue whale when it dives in search of food and found that it has only a few beats per minute.

Scientists have found that the largest mammal, the blue whale, which can reach a length of 30 meters and a weight of 200 tons, reduces its heart rate to just a few beats per minute during diving and searching for food.

The lowest number of beats recorded during the dive was two, and the highest after returning to the surface of the ocean to breathe air, was 37 beats per minute, writes Reuters.

"The blue whale is the largest animal and has fascinated biologists for many years," said biologist Jeremy Goldbogen of Stanford University.

Generally speaking, the larger the animal, the lower the heart rate. This minimizes the amount of work the heart has to do in distributing blood throughout the body.

In humans, the heart beats between about 60 and 100 beats per minute at rest, and about 200 beats per minute during exertion or exercise.

The smallest mammals, shrews, have more than a hundred beats per minute.

The scientists collected about nine hours of data, and attached an electrocardiograph to an adult male about 22 meters long that was located in Monterey Bay, off the coast of California.

Blue whales, despite their enormous size, feed on small prey. They filter large amounts of water in their mouths and extract prey such as planktonic crustaceans and other zooplankton.

During the foraging dive, the whale had an extremely low heart rate, usually four to eight beats per minute, sometimes only two. After he came to the surface again, his heart rate increased to 25 to 37 beats per minute, reports index.hr.