I heard it in the TV Series Fargo, Episode 9. Here is the transcript:
A: We still on for golf next week?
B: Course we are, Burty Burt.
A: But more importantly, are you and Louise still gonna make it on Sunday?
B: Do dogs smell each other's butts?
A: I think I might have observed that type of behavior on occasion.
Also in Prison Break, Season 1 episode 11:
A: You still interested in getting in on PI?
B: Does my momma got big breastices?
A: I wouldn't know.
B: Hell, yeah, she does. And hell, yeah, I do.
What is the name of this construction?
Best Answer
It's a called rhetorical affirmation.
The respondent answers by asking a rhetorical question.
The answer that is implied by the rhetorical question is the answer to the the original question.
In the Prison Break quote, the rhetorical question isn't sufficiently well known for the original questioner to determine if the respondent means yes or no, which is why they reply to the rhetorical question of Does my momma got big breastices? with I wouldn't know which then causes the respondent to supply the answer to both their own 'rhetorical' question and the original question.