Given the differences between a Great Dane and a Chihuahua¹, how do dogs identify them as being another dog at a distance?
Smell and sound are primary senses for dogs. Sight, not so much.
Smell and sound are primary senses for dogs. Sight, not so much.
when another dog is inside a car that just stopped at the intersection?
Another issue here is that smell of different dogs is supposed to have at least some variation as well (is this feature variation bigger or smaller than variation in size?), and if one dog is downwind then another is upwind - i.e. while smell obviously plays a major role in dog's sensing of the world we just can't ascribe it all to the smell. In my experience visual recognition plays major part in many cases as well (note: i'm not arguing which dog's sense is strongest, only that there are situations when visual is basically the only one that could have brought the information)