Any dog owner will tell you their dog can sense them coming way before any human can. But is that just our perception, or can dogs really tell when we're on our way home before we set foot in the building?
There is a general consensus among experts that dogs can indeed sense when we're coming home in advance. Although there is not yet a definitive answer as to how they know, there are a couple of hypotheses that would explain this phenomenon.
Research suggests that dogs and have humans co-evolved for something like 32,000 years. That means we've been evolving alongside each other and learning each other's habits for millennia. Dogs are hard-wired to pick up on human cues, and they can sense cues that we don't even know we're giving out.
Here's an obvious example: If you live in a house and drive a car to work, you've probably witnessed your dog get excited when she hears your car pull up in the driveway. That's because she's learned that the sound of that particular car means her beloved owner isn't far behind.
But what if you don't drive a car, or if you don't live somewhere with a driveway? That's where dogs' penchant for associative learning really kicks in. Matt Shipman at North Carolina State University gives this example: "if you take the subway and usually get home at 5:30, the dog may be triggered by the local bus that drives by every day at 5:25." There may even be other cues within your home. Maybe your partner or roommate always starts cooking dinner 30 minutes before you come home, or maybe they feed the cat 10 minutes before you come home.
In addition, dogs' amazing sense of smell might play a role in their advance knowledge of our arrival. In Alexandra Horowitz's book Being a Dog, she writes that in addition to dogs' incredible perception of environmental cues, "it might be that the odors that we leave around the house when we leave lessen in a consistent amount each day." In other words, your dog might know that your scent is strongest in the morning, and lessens to a consistent level each day. When the scent fades to that level, they know it's time for their owner to come home.
There aren't many studies on dogs anticipating their owners' arrival, so the above hypotheses remain hypotheses for now. However, one thing is certain: Dogs are amazing.