Inside of a Dog_ What Dogs See, Smell, and Know - Alexandra Horowitz [35]
Other animals also press their rear ends against the ground to release fecal and other anal odors. The mongoose does a handstand and rubs itself against a high perch; some dogs do what gymnastics they can, seemingly deliberately relieving themselves on large rocks and other outcroppings. Although secondary to urine marking, defecation also holds identifying odors—not in the excreta itself but in the chemicals dolloped on top. These come from the pea-sized anal sacs, situated right inside the anus and holding secretions from nearby glands: extremely foul, dead-fish-in-a-sweatsock kind of secretions with apparently individual-dead-fish-in-individual-sweatsock odors for each individual dog. These anal sacs also release involuntarily when a dog is afraid or alarmed. It may be no wonder that so many dogs fright at their veterinarian's office: as part of a routine examination, vets often express (squeeze to release the contents of) the anal sacs, which can get impacted and infected. The smell, covered for us by the familiar scent of veterinary antibiotic soaps, must be all over the vets: they reek of epic dog fear.
Finally, if these mephitic calling cards are insufficient, dogs have one other trick in their marking book: they scratch the ground after defecation or urination. Researchers think that this adds new odors to the mix—from the glands on the pads of the feet—but it may also serve as a complementary visual cue leading a dog to the source of the odor for closer examination. On a windy day, dogs may seem friskier, more likely to scratch the ground; they may in fact be leading others to a message that otherwise would waft away.
LEAVES AND GRASS
Science, out of decorum or disinterest, has not definitively explained Pump's mad wriggling in a funky spot of grass. The odor may be of a dog she's interested in, or of a dog she recognizes. Or it may be the remnants of a dead animal, rolled in not so much to conceal her own smell as enjoyed for its sumptuous bouquet.
We respond pithily and with soap: by giving our dogs frequent baths. My neighborhood has not only its fill of dog groomers, but is visited by a mobile grooming van that will come to your home to pick up, suds, fluff, and otherwise de-dog your dog for you. I'm sympathetic to owners who have a lower tolerance for detritus and dust around their homes than I do: a well-walked, thoroughly played-out dog is an efficient spreader of dirt. But we deprive our dogs of something by bathing them so much—to say nothing of our culture's overenthusiastic cleaning of our own homes, including our dogs' bedding. What smells clean to us is the smell of artificial chemical clean, something expressly non-biological. The mildest fragrance that cleansers come in is still an olfactory insult to a dog. And although we might like a visually clean space, a place rid entirely of organic smells would be an impoverished one for dogs. Better to keep the occasional well-worn T-shirt around and not scrub the floors for a while. The dog himself does not have any drive to be what we would call clean. It is no wonder that the dog follows his bath by hightailing it to roll vigorously on the rug or in the grass. We deprive dogs of an important part of their identity, temporarily, to bathe them in coconut-lavender shampoo.
Similarly, recent research found that when we give dogs antibiotics excessively, their body odor changes, temporarily wreaking havoc with the social information they normally emit. We can be alert to this while still using these medicines appropriately. So too with the laughable Elizabethan collar, an enormous cone collar typically used to prevent a dog from chewing at stitches closing a wound: it is useful to prevent self-mutilation, but consider all the ordinary interactive behavior it prevents—looking away from an aggressive dog; seeing someone's loping approach from the side; the ability to reach and sniff