Here's my new favorite joke

I was reading a back issue of Esquire magazine at the beach yesterday and came across their feature called "Funny Joke From A Beautiful Woman". In every issue, some scantily-clad actress or musician or model relates her favorite joke, and this month's joke was a doozy. Apologies to my blond friends; it's a "dumb blond" joke, and I have to admit I didn't get it at first (maybe I'm part blond?). But then I started snorting with laughter and read it out loud to Peter, who snorted out loud with me. Here goes:

After robbing a bank, a blond, a brunette, and a readhead duck into an alley where they hide in potato sacks. The cops first go to the sack with the brunette in it and kick it. The brunette says, 'Meow'. They go to the sack with the redhead in it and kick it. She says 'Woof, woof'. Last, they kick the sack with the blond in it and she says 'Po-ta-to'.