Why did the penguin cross the Antarctic?

It's one of the oldest riddles in the English language:
"Why did the chicken cross the road?"

The answers are sometimes simple and sometimes absurd. So why did the chicken cross the road? "To get to the other side, of course." Or: "Because the monkey was on the other side, and the chicken wanted to give him a banana."

"Why did the penguin cross the Antarctic?" No, that's not a riddle. It's the question the great film-maker Werner Herzog asks in his award-winning documentary Encounters at the End of the World.

So why did the penguin do it? Because he wanted to be alone? Because he wanted to get to the mountains and learn to fly? Because he wanted to be famous? Because... While you're thinking of a better answer, here's a chicken joke for you:

A man is driving along a road when he notices a chicken running beside his car. He's amazed, as he is doing 90 km/h. He accelerates to 100, and the chicken stays right next to him. When he speeds up to 120, the chicken passes him. The man sees that the chicken has three legs. So he follows it and arrives at a farm. He gets out of the car and sees that all the chickens there have three legs.
He asks the farmer, "What's with these chickens?"
The farmer says, "Well, everybody likes chicken legs, so I bred a three-legged one. I'm going to be a millionaire."
The man asks him how they taste.
The farmer answers, "Don't know. I haven't caught one yet!"