how much do whale hearts weigh
Well, in terms of its RELATIVE size (compared to the animal's mass), it isn't: it's something less than 1% of the animal's body size, which is not dissimilar to the equivalent size in humans. But in absolute terms... it is the size of an automobile. The heart of a blue whale weighs about a half a ton, 1000 lbs. It has to be large enough to pump about 15,000 pints of blood as compared to about 8 pints in a human.