Spy vs. Spy

I used to see this feature in Mad under the heading of “Joke and Dagger Department”; I know creator Antonio Prohías died about ten years ago, and this fact was not annnounced in the magazine.
What I would like to know is why Prohías–and later, Bob Clarke–drew the black and white spies with beaks. (Prohías always drew the gray woman spy normally.) My little sister–she was about ten years old then–said it was to make them look sinister.
Any comments?

Prohias didn’t want them associated with any given ethnic group.

And he wanted them identical, other than color, to make a point. I’m certain you can figure that part out.

Now if they weren’t spies but rather financiers and lawyers, everyone would be up in arms.