Dogs have a significantly more developed sense of smell than humans do -- they're equipped with millions more scent receptors, which they use to detect predators, prey and companions. While dogs typically prefer certain smells, this isn't as specific as one particular aroma that is universally appealing -- rather, there are different types of smells that canines generally gravitate toward.
Generally, dogs prefer smells that humans do not -- particularly, the smell of rot. They're attracted to odors that humans typically find unappealing, like the smell of a decomposing animal carcass, an open garbage bag or a pile of rotting leaves. In fact, dogs appreciate these smells so much that they won't just seek them out -- they'll roll in them, covering themselves in the odor so that it lasts for hours.
Scents That Disguise
Dogs prefer foul smells not just because it satisfies their apparent tastes, but also because it has practical use. As reported by canine specialist Dr. Stanley Coren in Psychology Today, dog preferences for foul smells -- and their habit of covering themselves in them -- may be rooted in their wild nature. Wild dogs roll in odorous substances like feces, rotten plants and dead animals as a way of disguising their own scents, allowing them to stalk prey without being detected as easily. While your pet doesn't share those concerns, the behavior itself is so deeply rooted that he may be unable to resist a roll in the smelly stuff.
Luckily, bad smells aren't the only kind that dogs prefer. For example, domesticated dogs demonstrate a recognition of and preference for smells associated with their owners. They may prefer gnawing on a dirty pair of underwear over a chew toy, or curling up on a pile of laundry over sleeping in their own bed. This is because dogs prefer the familiar smells of their pack -- for a wild dog, this means the smell of other dogs that they know and trust, like family members. In the home, it means their owners.
There is one particular smell that virtually no dog can resist: food. Dogs are natural hunters, and even a pet is naturally drawn to the aroma of food -- especially meat. Whether you are grilling a steak, carving a turkey or opening up a fresh can of wet dog food, it triggers your dogs olfactory senses and tells him that there is a meal to be had nearby. While your dog doesn't necessarily prefer the smell of just any food -- he won't likely salivate when you're chopping up basil or peeling garlic cloves -- meat is a consistent favorite among canines.