Long ago, on a land far away there once lived a creature with a big body and a short neck who loved stealing food from the grumpy old monkey who lived in a tree high in the sky, because the giraffe thought if he ate bananas his neck would get taller eventually. So the giraffe went on doing it anyways because he always thought the monkey wouldn't never do anything because all the monkey ever said was "Get your old ugly short neck self off my property before I show you what i'm working with?".
One day while the giraffe was on it's way to get some bananas the giraffe noticed it was quiet and there was no sign of the monkey, so the giraffe thought he had the right chance just to go and steal all the bananas he wants since he doesn't have to hear a big mouth monkey threatening him. But guess what? That giraffe had a rude awakening for him because, by the time the giraffe had gathered all the bananas and was on his way out, the monkey pulled out his chokers and was ready to show that short neck joker what he meant when he said he was gonna show him what he was working with.
Then the monkey gave him a few good punches and kicks leaving the giraffe on the ground to get back up. So the monkey left to his tree and said to himself, well done chokers you got the job done. Then the monkey was just half way up the tree when he had turned around to the voice of the giraffe saying "You ain't nothing but a punk." So the monkey had to think for a minute thinking, is this beat up giraffe really trying to stand up here and tell me I'm a punk when this fool is standing up here with a bleeding mouth and I got no scratch or no mark on me.
So, you know what?
The monkey slid down the tree and gathered all the bananas because the monkey said "If all that stupid giraffe wants to do is steal my bananas just to see if his neck grows then you know what, today is the day." That monkey gathered all his bananas and started shoving every last banana down the throat of the giraffed until eventually his throat was just the way he liked it, even though it was a little longer than he had expected because the monkey said "I wasn't playing. I was going to stretch that short neck fool until he learned his lesson."
So the next time you ask the question "Why do giraffes have long necks" you will know this is the story behind it.