You've seen your canine companion swallow food without even chewing it, leading you to wonder if it even matters to him what the food smells like, tastes like or even if it's food at all. With some particular dogs those issues are debatable, but in general dogs use their senses to decide what is worth eating. The senses of smell and taste are closely related, but your dog relies on smell more than taste.
Smell, Then Taste
Watching your dog deliberate whether or not he should eat something, it should be clear that his sense of smell guides him. Rufus smells first, then tastes, sniffing at something before gobbling it up. In their 2011 book for dog lovers Wendy Nan Rees and Kristen Hampshire write that dogs are attracted to particularly smelly foods, but sometimes eat so quickly they don't even taste what they're eating.
Effective Sniffers, But Not a Lot of Buds
Smell is more of a factor than taste when it comes to how your dog selects his food because of two reasons. First, Rufus' sense of smell is about a million times more effective than yours. It's a trade-off though, because the second issue is that you have about six times more taste buds than he does. Although he can taste sweet, bitter, sour and salty flavors, they don't register as strongly as they do for you when you eat the same items. That's why Rufus relishes the smell of something but then wolfs it down quickly, seeming to spend more time enjoying the smell of it than tasting it.
Rufus may not be able to taste as well as you can, but the fact that he can distinguish between different flavors helps him make taste associations, connecting the smell, taste and outcome all together. For instance, if your dog eats something that tastes bitter or even makes him sick, he'll quickly develop an aversion to it and avoid eating that same food again.
Senses of Aging Dogs
As your dog ages, any or all of his senses may change, decreasing in effectiveness. If Rufus' sense of smell and taste start to dull, you could have a hard time getting him to eat enough to keep him healthy. Entice older dogs to eat by enhancing the flavor of kibble. Try pouring low-sodium broth or the juice from a can of water-packed tuna over dry food, or mix it with a can of especially smelly canned dog food. Making it as fragrant as you can will make it more appetizing for your dog.