Stanford researchers report first recording of a blue whale's heart rate (2019)

Note they put a Holter monitor on it

https://www.pnas.org/doi/10.1073/pnas.1914273116

to get an ECG which is one of several strategies they could use. (e.g. lately I've been interested in Heart Rate Variability which has gotten me looking at reading heart rate with cameras, radars, pressure gauges, ultrasound, etc.)

30 BPM at the surface, 4 bpm while diving.

It’s interesting Genesis talks of whales before many other things.

Anyone got a direct link to or time index of the recording? I skipped around the video on the linked page but it was all music.

> Looking at the big picture, the researchers think the whale’s heart is performing near its limits. This may help explain why no animal has ever been larger than a blue whale – because the energy needs of a larger body would outpace what the heart can sustain.

Fascinating to learn such details!

A Whale's tachycardia is my bradycardia. Huh.

and the highest heart rate belongs to the smallest mammal

https://en.wikipedia.org/wiki/Etruscan_shrew

"The Etruscan shrew has a very fast heart beating rate, up to 1511 beats/min (25 beats/s) and a relatively large heart muscle mass, 1.2% of body weight."

(to illustrate - machine guns typically do 600-900 rounds/min)

I wonder whose muscle fiber is stronger per unit mass - the whale's or the shrew's...