The short answer is no, and that’s thanks to their very special cardiovascular system.
A giraffe’s heart is two feet long and can weigh up to 25 pounds. It pumps blood so effectively that giraffes have the highest known blood pressure of any mammal—280/180 mm Hg. But when a giraffe bends down to drink, a series of adaptations prevent blood from rushing to its head: Absorbent,elastic artery walls swell to hold excess fluid while valves in the jugular prevent blood from flowing back. When the animal lifts its head, the blood vessels become pulmonary traffic cops, directing most of the blood straight to the brain.The jugular is even outfitted with a special muscle to give blood an extra boost upward, and all this prevents wooziness from setting in.