How Giraffes Handle High Blood Pressure

Very well, it seems:

To most people, giraffes are merely adorable, long-necked animals that rank near the top of a zoo visit or a photo-safari bucket list. But to a cardiovascular physiologist, there’s even more to love. Giraffes, it turns out, have solved a problem that kills hundreds of thousands of people every year: high blood pressure. Their solutions, only partly understood by scientists so far, involve pressurized organs, altered heart rhythms, blood storage, and the biological equivalent of support stockings. 

Giraffes have sky-high blood pressure because of their sky-high heads, which, in adults, rise about six meters above the ground—a long, long way for a heart to pump blood against gravity. To have a blood pressure of 110/70 at the brain—about normal for a large mammal—giraffes need a blood pressure at the heart of about 220/180. It doesn’t faze the giraffes, but a pressure like that would cause all sorts of problems for people, whether heart failure, kidney failure, or swollen ankles and legs.