Dogs understand more than we give them credit for. If you think about it, it’s not hard to believe.
They have no words. And yet they live in a complex social structure of the pack, which is group dynamics but also the dynamic of their relationship with individuals and even within the hierarchy of the parents and pups.
Dogs become masters of the most subtle forms of facial expressive communication, demeanor, even energy level.
Add to that, that they can smell 200 times more acutely then we can, they very probably can actually smell fear.
Their visual and auditory acuity adds additional input to what they perceive of the world.
And then, add to that, they really care about us. Individually, we really are their pack. Not only do we ensure their survival by “strength in numbers“ but we also facilitate their eating, the safety of their rest, even their physical protection. Which is a mutual give-and-take whether they can contribute to ours or not. They would if they could.