Blue Whales’ Hearts Can Beat Exceptionally Slowly

Henrietta Brewer
November 26, 2019

The researchers's evaluation means that the blue whale's coronary heart is working at its restrict, which can clarify why the creatures have by no means advanced to be any larger.

The researchers from the Stanford University in the United States used four suction cups that secured a sensor-packed tag near the whale's left flipper, where it recorded the animal's heart rate through electrodes embedded in the centre of two of the suction feet. Studies like this add to our fundamental knowledge of biology and can also inform conservation efforts.

Goldbogen said, "Animals that are operating at physiological extremes can help us understand biological limits to size".

In a Standford University press release, he said the whales might be particularly susceptible to changes in their environment that could affect their food supply, which could make studies like these key to the conservation of the endangered species.

The blue whale is notable for being the largest species on Earth.

I genuinely thought it was a since quite a while ago shot since we needed to get such a large number of things right: finding a blue whale, getting the tag in the ideal area on the whale, great contact with the whales skin and, obviously, ensuring the tag is working and recording information, said Goldbogen in an official statement. After suction-cupping a pulse monitor to the back of a blue whale off the California coast, the researchers watched as the gargantuan creature dove and resurfaced nonstop for almost 9 hours, alternately filling its lungs with air and its belly with schools of tasty fish hundreds of feet below the surface. The suction cup tags were out onto the whale without knowing if they would stay on due to the accordion-like skin of the whale that stretches when it opens its mouth to feed.

Researchers have measured the heart rate of emperor penguins as they dove in the Antarctic. The data it captured showed striking extremes.

The biology of the blue whale has long fascinated physiologists because of the animal's extreme size.

Professor Goldbogen and colleagues found that blue whales slow their heart rate for deep dives, but expend energy to lunge forward and engulf water for filter feeding. The highest heart rate - 25 to 37 beats per minutes - occurred at the surface, where the whale was breathing and restoring its oxygen levels.

This natural cardiac limit may explain why blue whales max out at a certain size, and why there have never been any known animals on Earth any larger.

The experts discovered that the blue whale lowered its heart rate to as little as two beats per minute when it dived for food.

Once the whale returned to the surface, its heart rate jumped further still, beating at between 25 to 27 bpm on average. This nearly outpaced what the researchers expected, but it was the minimum heart rate that really caught the researchers by surprise, being around 30 to 50 percent lower than they'd expected. Meanwhile, the impressively high rates may depend on subtleties in the heart's movement and shape that prevent the pressure waves of each beat from disrupting blood flow.

"The heart rate data are consistent with allometric predictions based on body mass and the heart rate data confirm anatomical-biomechanical models of vascular function in such large animals". They'd also like to use their ECG suction cup device to measure the heart rate of fin whales, humpback whales, and minke whales.

"A lot of what we do involves new technology and a lot of it relies on new ideas, new methods and new approaches", said Cade. "We always seek to expand the limits of how we can learn about these animals".

This research was funded by the Office of Naval Research, a Terman Fellowship from Stanford University and the John B. McKee Fund at Scripps Institution of Oceanography.

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