It is prey behavior alright but the dog knows where it's food comes from, and it is usually a bowl. So it is going through the motions with a simulated prey, ie the ball, or tug or sleeve, frisbee etc from instinct.
Prey drive is stalking, chasing, catching, shaking and disecting. You will see dogs simulate these behaviors all the time with toys or eachother. They are training and exercising them selves instinctually imo. Ever wonder why pups destroy things or shake toys.
Prey drive - Wikipedia, the free encyclopedia