Did you know, that of all domestic animals the horse …
…, that of all domestic animals the horse has the most powerful heart?
It weighs about 3 kilogram, in racing horses up to 5.2 kilogram and circulates about 60 litre of blood through the body.
By comparison, an adult human has about 5 to 6 litre of blood and the heart weighs 300 to 350 gram on average.