Have you ever walked through your front door after a grueling day, having said nothing to anyone and keeping your "I’m fine" face firmly in place, only to have your dog immediately lean against your legs or rest their head on your lap? You might think they’re just being sweet, but the truth is much more profound: Your dog knew you were struggling before you even realized it yourself.

In this episode of The Animal, we peel back the curtain on the invisible, chemical world that exists between you and your canine companion. We often think of emotions as private, internal experiences tucked away in our thoughts, but they are actually physical. Every feeling you have—from the sharp spike of stress to the heavy fog of sadness—triggers a chemical reaction in your body that "leaks" out through your sweat a ...