One of the tiniest mammals in the world, the Etruscan shrew, has a heartbeat that may reach 1,500 beats per minute or 25 beats per second.
In contrast, the human heart beats slowly, only 60 to 100 times per minute.
The largest mammal to have ever lived, the blue whale, also had its heartbeat examined.
These marine monsters can reach lengths greater than two school buses, and their hearts, which weigh more than 1,000 pounds and are about the size of a couch, beat as little as twice every minute.
The Heartbeat of the Biggest Animal Ever
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When the animal dove, its heartbeat was gentle, but when it surfaced to breathe, the rate suddenly increased and reached as high as 37 beats per minute, as per Vox.
Scientists have developed a method to hear the heartbeats of wild whales in recent years.
They aren't particularly interested in monitoring these animals' health; rather, they are attempting to provide an answer to one of biology's most fundamental questions: how big can an animal grow on Earth?
The larger-than-dinosaur blue whales' heart rates suggest that heart size may be a limiting factor for body growth.
And with more sophisticated monitoring equipment, could also assist researchers in defending these marine giants from one of the ocean's most enigmatic dangers.
Larger hearts beat more slowly and replace the body's oxygen supply more slowly.
As a result, whales must spend more time at the surface to catch their breath, taking away from the limited time they have to consume a seasonal food source like krill.
These behemoths might not have enough time to eat if their hearts are too large.
Theoretically, these organs should be reaching their maximum speed when the whales come up for air if the size of their hearts is restricting them in any way.
When researchers went out to detect a blue whale's heartbeat in 2018, one of their goals was to learn this.
These creatures have two separate heart rates, according to blue whale heart rate statistics.
The whale is diving and trying to preserve oxygen, which is when the heartbeat is slow. The second happens quickly when the whale is back at the surface and its heart begins pumping quickly to resupply oxygen.
Big bodies may cause issues there, on the surface, as researchers had hypothesized.
How Scientists Detect The Heart Rates of Marine Mammals
The use of animal-borne devices for physio-logging, which records physiological characteristics, is entering a new phase as a result of developments in sensor technology.
Existing datasets, however, gathered with conventional bio-loggers, like accelerometers, nevertheless hold latent eco-physiological data, as per Journals.
While IMU tags are easier and have fewer logistical restrictions, physio-logging tags with cutting-edge biomedical technology are pushing the limits of physiological field research.
These tags also give researchers access to more species and greater sample sizes.
This is crucial for species that cannot be restrained or researched in controlled environments.
In both managed care and the wild, the ballistocardiogram (BCG) has the potential to be used to monitor heart rate with accelerometers.
The sample rate should be carefully considered when reviewing the bio-logging data that has already been collected and when organizing the placement of new tags for BCG analysis.
As a general guideline, the sampling rate for signal processing should be at least twice as frequent as the phenomenon of interest.
The BCG waveform's frequency, not the heart rate, is the one that matters in this situation.
In humans, the IJK complex's power, which is the portion of the BCG waveform used to detect heartbeats, is focused between 4 and 7 Hz.
Due to their often larger bodies, marine mammals' BCG waveforms are unlikely to have a greater frequency than those of humans.
As a result, BCGs may be produced at accelerometer sampling rates as low as 10-15 Hz.
BGC technique may be used to mine existing datasets and better understand how heart rate scales with body size and other biological parameters as accelerometer tags have been used on numerous cetacean species for many decades.
Additionally, it might offer more information for applications in conservation physiology.
BCGs from gliding phases before and after controlled sonar exposure trials, for instance, could measure the body's reaction to anthropogenic disturbance.
