Dogs are social creatures and from a young age will play, or roughhouse with each other. Often goofy when they play chase (or fetch) games, dogs are actually fine-tuning predatory skills when they do this.
It teaches them how to accelerate, turn or stop quickly, and how to pounce with accuracy.
“If deprived of play predatory opportunities, dogs may resort to vacuum chasing of imaginary creatures, may pace, circle, or chase their own tails. This is a sad state of affairs,” Pet Place writes.