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A PetCo advertisement encourages us to,“Keep your pup smelling delicious between baths with Petco's selection of dog perfumes, colognes, and deodorant sprays.” But my dog Bella will be the first to tell you that she really doesn’t want to smell like papaya or baby powder. She would much rather smell like Bella. A dog’s scent is her identity. We may not be aware of our own odor, but dogs are most certainly tuned in to their own scent profile. Each dog has a unique “scent identity,” an olfactory sense of who they are, which is crucial to their own self-identification and is a critical element in their interactions and communications with other dogs. Being aware of and even protecting a dog’s individual scent identity is an important, but often overlooked, component of canine welfare.
In understanding the importance of what I’m calling a dog’s scent identity, recall that dogs “see” the world through their noses. The dog’s nose is a work of art. (Here's a nice PBS video on the canine sense of smell.) The noses of dogs are generally much bigger than human noses and the olfactory center in the canine brain is proportionately larger than that of the humans, so more of the brain is dedicated to processing olfactory information. Dogs have 125-300 million olfactory receptors compared to our measly six million. On average, their sense of smell is about 1000 times more sensitive than ours. They can track multiple smells at the same time and sniff approximately five times a second.
Dogs communicate a great deal to each other through scent. Dogs have scent memory and remember each other by smell more than by sight—and can even remember the smell of a canine friend after years apart. A dog can tell where another dog has been, and even how the other dog is feeling, through the dog’s unique olfactory profile. A dog likely has an enduring scent “signature,” but scent identity also will be continually in flux depending on where she has been, who she has seen, what she has eaten, and how she is feeling.
So, washing a dog in strong-smelling shampoos, or spraying her with perfume, may rob her of a sense of “feeling like herself.” Because dogs communicate with one another through odor, changing their smell by washing it off or covering it up with perfumes will likely make communication with other dogs more challenging. I don’t believe anyone has conducted research on the effects of shampoos or deodorizers on dog communication, but my guess is that a “de-odorized” dog’s ability to send clear olfactory signals to other dogs is compromised. So, maybe in the spirit of allowing dogs to be dogs, we should allow them to smell like dogs as much as possible.
Beyond sense of sense and communication, we might also wonder whether strong artificial odors are aversive to dogs. Odors are powerful triggers for us and we aren't remotely as smell-oriented as dogs. Being exposed to a strong odor over an extended period or being continuously bombarded with the same odor may lead to a feeling of sensory overload. (Think of the last time you were trapped in an elevator with a person who went overboard on perfume or cologne.) Powerful body perfumes, strong disinfectants, heavily scented candles, or spray air fresheners might essentially be nasal assaults on our dogs. Does this mean that you should never wear perfume or cologne if you live with a dog? Never burn incense? Never douse the dog bed with Febreeze? No, it doesn’t, but your dog will likely appreciate it if you show some restraint. Dogs are already awash in artificial scents, from the laundry detergent we use to the formaldehyde in our carpets and furniture to the mint in our toothpaste. Dogs trying to live in a human-dominated world have their senses assaulted every second of the day, and we can help by giving them a break from too many strong, artificial scents.
People who work with dogs are already thinking about aversive odors. For example, aware that the strong smells of chlorine and other disinfectants are aversive to many dogs, veterinary clinics following the Fear Free model developed by Dr. Marty Becker are using cleaners without strong chemical odors, such as hydrogen peroxide. These cleaners are also designed to reduce the fear pheromones left behind by other dogs who have visited the clinic. Some veterinarians, trainers, and researchers are also experimenting with aromas that dogs find calming, such as lavender—an area of sensory enrichment that holds great promise.
In trying to create a comfortable home environment for our dogs, we can think about odors from their perspective. We might find comfort in Tide Fresh Ocean scented sheets, whereas dogs likely prefer something familiar, dirty, and doggy. When we leave dogs alone for the day, it might be comforting for them to be surrounded by odors that relax them, and these could be doggy odors with which they’re familiar, such as those they associate with themselves, their favorite humans, or other pets in the home. Bringing along a favorite dirty pillow or stinky stuffed toys—something with odors that will be familiar—might help a dog feel more at ease and less anxious when you move to a new home, take a dog on vacation, leave your dog at home with a friendly dog-sitter, or take your dog to their favorite canine B&B when they can’t join you on a trip.
One final aspect of scent identity—and something that makes many human companions of dogs cringe—is when our dog suddenly darts off and next thing we know, she is on her back like an upside-down beetle, legs waving as she smears as much feces, dead thing, or rotting grass clippings as possible into her fur. There are limits to just how much doggy odor we can tolerate and sometimes a bath is absolutely necessary.
Ethologist Marc Bekoff and I talk about the importance of scent identity in our book Unleashing Your Dog: A Field Guide to Giving Your Canine Companion the Best Life Possible (New World Library), which is scheduled for release on March 6, 2019.
