Why does my dog chase cats?

No. It is their prey drive. It is natural. Unless trained otherwise, they will do that.

No.

Predatory behavior is innate to the species and chasing prey animals and birds is an exciting behavior that is hard wired into the mind of a dog at conception and if not trained against it to stop/not act on what is a natural instinct when told, it will repeat it and not in itself indicate a vicious temperament.

Prey drive. The cat runs which is an invitation to chase. My friend has a siamese that doesn't' run and none of the dogs will bother to chase her but the other cats will run when they see the dog therefore they chase. them.

No. All dogs chase cats. It's a law. Cats irritate dogs, dogs chase cats. If they don't they can get arrested..

They think cats are annoying and keep getting into their business so they chase them away. It's totally natural. Or they guard like my dog. She barks at helicopters. :) lol

Because the cat looks at them funny

Probably the same motivation he has to chase a ball. If he caught the cat, he'd probably bring it back to you to throw for him!

because their natural enemies. and its fun for the dog to chase something living

because the cat runs.

no ...