FUN FACT:  The extreme height of these animals has led to some amazing physiological adaptations.  Giraffes have the same number of vertebrae in their neck as humans (7), but each is much larger.  When standing, a giraffe’s brain is 9 feet above its heart, but when the giraffe lowers its head to drink it is 6 feet below the heart.  In most animals, this sudden change of 15 feet would cause ruptures in blood vessels and hemorrhaging in the brain, but this is prevented by special elasticized arteries and valves in the neck that prevent changes in blood pressure.