Why would a 2009 Ford Escape make a dog bark sound when accelerating after a stop?

I JUST bought a 2009 Ford Escape and notice that everytime I accelerate after a stoplight or stop sign, my engine makes 1 or 2 quick dog bark sounds. Anybody know what that could mean?|||u sure ur not "chirping" the tires???|||Sounds like you've a dog in your engine.