The blue whale is the largest animal that has ever lived. It can reach 30 meters long and weigh as much as 181,000 kilograms. The animal's heart alone weighs more than a fully grown cow. For the first time ever, scientists have recorded its heart rate.
Stanford University ocean biologist Jeremy Goldbogen led the study of the blue whaled heart rate. To get this reading, the researchers attached an electrocardiogram device(心电图设备) to the body of a blue whale. They recorded nine hours of information on a 22-meter-long male from the Pacific Ocean off the coast of California. The data did not come easily.
"First, we have to find a blue whale, which can be veryarduous," Goldbogen said, because these animals live across massive areas of the open ocean. But, with years of research experience and some luck, he explained, the team was able to position a small boat along the whalers left side.
Then, the researchers connected a special recording device to a very long pole. As the whale surfaced to breathe, they quickly put the device as near to the animal's heart as possible. The small device had four suction cups(吸盘) on it, permitting it to remain on the whale for several hours.
They found out that when the blue whale dived for food, its heart rate dropped to between 4 to 8 beats per minute—with the lowest being two beats per minute. At the bottom of the hunting dive, the whale's heart rate rose to about 2. 5 times the minimum and then decreased again. Once the whale got its fill and began to surface, the heart rate increased. The highest heart rate — 25 to 37 beats per minute — occurred after the whale came out of the water for air. The findings are different from what scientists have already known — larger animals have slower heart rates. Therefore, they believe that such research helps scientists understand how huge animals operate.
