We take units of time like minutes, hours, and days forgranted, but time in general is an abstract concept that's beyond your dog's ability to perceive. Certainly a dog doesn't recognize defined time segments, such as an hour or day. However, dogs always seem to know when it's time to go for a walk or be fed, and many owners say their dogs seem to know when they're about to arrive home. This is because dogs learn to recognize routines.
Dogs learn by association. For example, a dog burns his paw on the stove so he learns not to put his paws on the stove in the future. The same theory applies when dogs observe their owners' behavior. If you always put on your coat before leaving the house, your dog will learn that this action means he's about to separated from you and will adjust his behavior accordingly.
All day long your dog is exposed to triggers that help him understand what's going on. Maybe you get up, then let him outside, then fill his food bowl or give him a walk. Then he might sleep for a while because nothing else is going on. Collectively, these events form a daily routine, ending with retiring to bed. While your dog doesn't understand that the Earth has rotated, he knows that when the TV goes off and you put on your pajamas, it's time for bed.
Your dog's ability to make associations with triggers means he can anticipate events accurately. If your dog is always waiting at the door when you arrive home, it's not because he can tell it's 5:40 p.m. It's most typically because a series of events have occurred that add up in his brain. Maybe your neighbor always arrives home 10 minutes before you, so when he hears the neighbor's car, he knows yours is likely to be next. His hearing is exceptional, so he can probably hear your car a block away and he gets excited. Then he hears the gate and smells you. By the time your key is in the lock, he's riled up and ready to greet you.
Dogs understand triggers, but there's a finite period of time in which a dog can form an association. That's why it makes no sense to punish your dog for something he did 10 minutes ago.
Although dogs are incapable of understanding time, they do react differently to stimuli depending on the amount of time they're exposed to it. A hungry dog will become more desperate for food the longer his access to food is restricted. Eventually, he'll go to his food bowl and nudge it with his nose. To a dog owner, this looks like the dog knows it's dinner time. Similarly, dogs with separation anxiety become more anxious the longer they're left alone, although you can teach them to cope with this by gradually exposing them to the stimulus of isolation for longer periods. Time-related intensity means you should always try to limit the amount of time your dog is left without stimulation.
By Simon Foden
Animal Planet: Can Dogs Understand the Concept of Time?
Random House: Dogs that Know when their Owners are Coming Home
The Humane Society of the United States: Separation Anxiety
Andrea Arden: How do Dogs Perceive Time?
About the Author
Simon Foden has been a freelance writer and editor since 1999. He began his writing career after graduating with a Bachelors of Arts degree in music from Salford University. He has contributed to and written for various magazines including "K9 Magazine" and "Pet Friendly Magazine." He has also written for Dogmagazine.net.