We have checked the pulse of a wild-living blue whale for the first time and discovered that the animal’s heart beats surprisingly slowly while it is feeding
Source:
https://www.newscientist.com/article/2224674-a-blue-whales-heart-beats-just-twice-a-minute-when-it-dives-for-food/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home