What’s the Difference Between a Duck?

Last night, I read this joke while browsing the internet and doing some research for my homework. It went something like this:

What’s the difference between a duck?
One leg is both the same!

I read it about three times before scratching my head and going to Google for an explanation. Even after Googling "What’s the difference between a duck," I was unable to find a valid explanation to what it actually meant. It drove me crazy for the rest of the night, and I was unable to concentrate on my home­work. It’s not often when something confuses me this much. I ended up going to sleep an hour earlier than normal.

Today, during school, I asked many of my friends and teachers, but their responses were unhelpful. A majority of the people I asked responded with "A duck and what?" Others responded with completely random answers, like names of fruit and European countries. One person said that his dad told him this joke when he was younger, but he hasn’t been able to understand it since.

After much contemplation, I devised the best explanation I could of the joke:

The joke itself is a paradox, and is supposed to be funny because it makes fun of "What’s the difference" jokes. You hear them all the time: "What’s the difference between your mom and my mom? Yo mama is fat, and mine isn’t!" Note how "What’s the difference" jokes compare two different things, but only one object is given in the joke.

The answer has a grammatical error with plurals: "One leg is both the same." You cannot compare two things and state they are the same when you are only dealing with one item.

If you haven’t made the connection yet, this whole joke is a play on plurals. When you hear "What’s the difference," you’re expecting two items to compare, but you get one (a duck). When you hear "both the same," you’re expecting two items that are identical, but you only get one (one leg).

If anybody disagrees with my explanation, I would like to hear yours, seeing as I’m not 100% sure if my explanation is anywhere near what the joke really means.