Blue whales are the largest, and potentially most majestic, mammals on the planet. They can grow up to 100 feet in length, and weigh up to 150 tons! Scientists have long studied the blue whale to greater understand the way it lives, how it’s body functions and thrives as it does at such a massive size. For the first time ever, scientists have gained a greater insight into an aspect of the blue whale’s anatomy that can be considered one of the most important bodily functions in all living things; its heartbeat.
Scientists have never been able to properly take a blue whale’s heartbeat. It’s massive size, thick blubber, and constant mobility made it nearly impossible for scientists to create a device that would accurately take a reading of the whales heartbeat; until now. According to Live Science Magazine, a team of marine biologists were finally able to take the measurements by combining a pulse monitor with suction cup technology that allowed for the monitor to stay stable and attached to the blue whales back. The research took place off the coast of California, where scientists watched and recorded the blue whale diving and resurfacing for nine hours straight. Blue whales do this to alternate between filling their lungs with a high amount of oxygen for their deep dives, and then filling their stomach with hundreds of thousands of tiny fish that are below the surface.
As the scientists were monitoring the whales heartbeat, they made a very intriguing discovery. The average heart rate of the blue whale that was studied was four to eight beats per minute. The highest it got during its deep dive was 34 beats per minute, and the lowest was a whopping two beats per minute!
The study based on this data was published this week in the journal Proceedings of the National Academy of Sciences, which concluded that “the simple act of catching a bite [to eat] may push a blue whale’s heart to its physical limits and that could explain why no creatures larger than blue whales have ever been spotted on Earth. Animals that are operating at physiological extremes can also help us understand biological limits to size,” lead study author Jeremy Goldbogen, an assistant professor at Stanford University in California, said in a statement.
The study is revealing the science behind how the Earth’s largest creatures develop an anatomy strong enough to keep such a massive living being alive. Blue whale’s hearts are, on average, around 400 pounds, and are roughly the size of a golf cart. While that data is staggering, it makes sense considering that heart needs to pump blood in an animal that’s about the size of two large school buses.
While the team of marine biologists expected that the blue whale’s heart rate would be relatively slow, the data they recorded was 50% slower than what they originally hypothesized. The study meticulously measured how long the whale was under the surface of the ocean, at the surface, diving, breathing, etc. What they found was that the whale’s longest dive lasted a total of 16.5 minutes and had traveled 600 feet below the ocean’s surface in that time. The whale also didn’t spend any more than 4 minutes at the surface to refill its lungs.
As the whale got progressively deeper and deeper, its heart rate slowed down. Scientists know this is because their bodies are more concentrated on distributing whatever oxygen is in the whale’s lungs to their heart and brain exclusively. On the opposite end, when the whale would come back up to the surface, it’s heart rate would accelerate up to 25-37 beats per minute. This occurred so that the whale’s bloodstream could rapidly distribute oxygen throughout its entire body and recharge it for the next dive. Researchers believe that it’s unlikely the massive heart of the blue whale would have the capability of beating any faster than that, hence the limit to its size and why the Earth doesn’t have any other animal larger than it.
Eric Mastrota is a Contributing Editor at The National Digest based in New York. A graduate of SUNY New Paltz, he reports on world news, culture, and lifestyle. You can reach him at email@example.com.