An adult giraffe can grow up to 18 feet tall.
Their long necks help them reach leaves high up in trees , especially acacia trees , which are their favorite. Interestingly, giraffes have the same number of neck bones as humans-just seven. Their tongues are also dark purple to protect against sunburn. A giraffe's heart weighs about 25 pounds , which is as heavy as some small dogs! This large heart pumps blood up their long necks to their brains. Giraffes sleep less than two hours a day, often standing up. Baby giraffes , called calves , can stand and walk within an hour of being born. Male giraffes sometimes fight by swinging their necks, a behavior known as 'necking.'. These battles usually end without serious injury.