The Blue Whale's Heart

The blue whale has the largest known heart of any animal. A preserved specimen found on the coast of Newfoundland weighed about 180 kg. Its heart rate changes with behavior: in one field study, rates during dives were typically 4–8 beats per minute and reached a minimum of 2; after dives, surface rates were 25–37 beats per minute. These are measurements from a particular whale, not universal values for every blue whale.