We absorb your breath through your monitor and use it to power our Internet machine.
The exception to the rule is, of course, dogs. Dogs can totally "catch" your yawn. Researchers aren't exactly sure why this is (they don't even know why yawning is so contagious among humans), but they speculate that humans have used yawns to indicate exhaustion since back in the day when language was little more than a series of farts and punches. Natural selection favored dogs that could communicate with us in as many ways as possible, and yawning just turned out to be one of those ways.
Digital Vision./Digital Vision/Getty Images
"If you're exhausted, I'm exhausted too, because I love you."
What's more, when we're down in the dumps, dogs feel bad for us. The physical ways they respond -- tails tucked, heads bowed, bestowing our faces with tender, dog-sack-scented kisses -- is a form of consolation. This is why dogs make such fantastic therapy animals: It's like having a free shrink who follows you around, listens without interrupting, and works for table scraps. So obviously dogs have an uncanny ability to read our emotions ... but how? Well, it's because all humans, whether right- or left-handed, display our emotions predominantly on the right side of our faces. When we're looking at each other, whether gauging prospects for romance or assessing the likelihood of a knifing, it's the right side of the face we look at. It's called left gaze bias, and the only species known to do it are humans, rhesus monkeys ... and dogs. Although hopefully your dog is looking for neither romance nor potential stab buddies.