Hello everyone.
When I heard this riddle when I was about 11 years old (just a coup’la years ago 
) I “got” this riddle right away and found it quite clever, but darn it if I could explain this riddle to anyone else. I have asked this riddle of many, and maybe two or three others “got” it, but they could not explain it either.
So, riddle me this, Batman!:
Why is a bird?
Because a vest has no sleeves.
Your explanations, please.
There are variations of this joke that use something like an orange or a bicycle instead of a bird. And the wording might be different.
So it’s clear the answer of a vest having no sleeves does not have some subtle meaning that relates to a bird and that the listener is supposed to figure out. There’s no hidden depth in the riddle.
The point of the joke is that it’s a nonsensical question with a nonsensical answer.
See ‘Anti-humor’ or ‘Anti-joke’
When I was a kid, my friend found a book of 1001 riddles in his Grandma’s house. One of the riddles was this:
Q. When is a hat not a hat?
A. When it’s a girl.
We decided that this was the 1001st riddle.
No soap, radio.
But back before I was wise as to the ways of the world, I never “got” two jokes that my friends laughed about:
Why does Dr Pepper come in a bottle?
Because his wife died.
If you were on an airplane and the stewardess offered you TWA milk, TWA coffee, or TWA tea which would you choose?
I was too naive.
Similar one from a roomie eons ago:
What’s the difference between an orange?
Because a banana is this color. (hands held about a foot apart when saying this)
I thought it was hilarious in its inanity.
“And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does.”
On googling, it looks like the punchline got mangled from “when it becomes a young lady”.
Those would definitely eluded me until I was, oh, maybe 17 or so? Here’s one I first heard age 11 that it took me a full 24 hours to figure out:
Why did the architect have his house made backwards? So he could watch the game on TV.
It doesn’t even make sense, but it’s funny if you’re new to innuendo, I guess.
Couple more for the OP, as told to me by my grandfather:
Why is a mouse when it spins? The higher, the fewer.
What is the difference between a duck? One leg, both the same.
That’s the one I was going to post (though with the answer “A leg, because either is both the same.” )
Not to be confused with the Marx Brothers’ “Why a duck?” routine:
What’s the difference between a crocodile?
It is longer than wide.
The version I have heard is:
One of it’s two feets is the same.
One of its feet is the same.
Along those lines, one I didn’t get as a kid was “what’s grey and comes in quarts?”
“An Elephant”
There was a sorta kid-friendly version, to which the answer to the same question was “Instant Elephant”.
If a chicken and a half can lay an egg and a half in a day and a half, how long would it take a frog with a wooden leg to kick all the seeds out of a pickle?
Wow, that’s both clever and thought provoking.
Related joke:
What should you do if an elephant comes in the door?
Swim for the window.
I suspect that you may be correct. That was only about fifty-some years ago. We probably didn’t understand it back then.
Thanks. That’s one mystery that I won’t ever worry about again.
What do you do with an elephant with three balls?
Walk him, and pitch to the rhino.
Clever!