How fast does a blue whale's heart beat?

The blue whale, also known as a sulfur-bottom whale, or by its Latin name, Balaenoptera musculus, is the largest animal known to have lived, with an average weight of 150 tons and a maximum length of 30 meters (m).

A host of mind-boggling figures characterize this colossal animal: Calves are about 8-m long and can weigh up to 90 kilograms (kg), an adult whale has about 100 long grooves on its throat and chest, and only its heart can weigh up to 700 kg — but how fast does this huge vital organ beat?

Understanding physiological parameters, such as this mammal's heartbeat, enable researchers to understand better its evolution, as well as better manage and preserve the species, which some list as endangered.

To find out how fast such a large heart can beat, researchers from Stanford University in California set out to place electrocardiogram sensors on a blue whale in Monterey Bay.
Jeremy Goldbogen, who is an assistant professor of biology in the School of Humanities Sciences at Stanford, is the lead author of the paper that details the exploits of the research team. The scientists collaborated with Paul Ponganis, from the Scripps Institution of Oceanography.

Placing electronic sensors on a blue whale
The scientists had previously measured the heart rates of emperor penguins using a tag full of sensors, and they then decided to try out the system in whales.

The team trialed the sensor tag in small, captive whales, and it succeeded. However, applying the tag to a blue whale in the wild was a different feat altogether that entailed various other challenges.
Firstly, people have trained captive whales to flip their bellies up, which allows for easier access. Secondly, the grooves on the blue whale's underside enable the large mammal to expand a great deal when feeding, thus making it easy for the tag to detach.