[onewhippedpuppy]

That applies to most animals, we just notice it more in dogs. It's pretty common knowledge that farm animals start going nuts when a tornado is approaching, before humans can detect it. I recall a news bit about a hospital that had a pet cat, and the cat would "tend to" the terminal patients. It knew they were going to die before the doctors did, and would stay in the room, often curling up on the bed. Dogs have a keen sense of people's intentions, and good vs bad people. I think in many ways we also have this ability, but are too smart for our own good and tune it out.