P.J. Denyer
Penultimate Amazing
The unfortunate dog knew it was in big trouble because of course it knew what it had done and realised this had been a bad move because dogs are so sensitive to social cues in their 'pack'.
Worth noting the owner also sensed that the dog knew things were bad, because humans too are sensitive to behavioural cues and not because they had some kind of sixth sense either.
Dogs don't feel guilt about past events the way we do, they react to our reaction to events, when you are angry at them they act in a way to mollify you which involves the actions we think of as a dog acting guilty, they'll act the same wayeven if they're not responsible for whatever is the cause of your anger.
In this case the dog would have known something was going on, that it's owners were upset and they were acting differently toward it, that's enough to explain it acting differently, add to that the owners projecting their own feelings on to that behaviour and it's more than enough to explain their perception of events.