Being a dog Following the dog into a world of smell

AS A COLLEGE STUDENT, I had a black-and-white kitty named Plexie. About once a month, I would take Plexie on my bicycle (I lived in the Netherlands) in a bag with her little head sticking out, to go on a play date with her best friend, a short-legged puppy. The two of them had played together since they were little, and kept doing so now that they were adult. They would race up and down the stairs of a large student house, surprising each other at every turn; their obvious joy was highly contagious. They could go at it for hours until they'd plop down, exhausted. Dogs and cats have more in common than people assume. They are both predators eager to chase and grab moving objects, which is why they potentially get along so well. They are also both mammals, which helps them relate to us. Mammals recognize our emotions, and we recognize theirs. It is this empathic connection that attracts humans to domestic cats (600 million worldwide) and dogs (500 million) rather than iguanas or fish. But we also know the differences, which range from sociality - descended from pack hunters, dogs are far more gregarious and cooperative than cats - to the senses, with canines relying more on olfaction and felines more on vision. A dog is basically a nose with a body attached to it as Alexandra Horowitz explains in "Being a Dog." Her fascinating book will open many eyes to the often forgotten world of airborne chemicals. We humans have an impoverished vocabulary to describe smells, and tend to overlook how much they affect our behavior. Given how well we remember the olfactory landscape of our youth, and how easily we tell the smells of human genders apart as well as recognize our siblings, this is rather surprising. We look down on this sense, considering it so animalistic that Sigmund Freud rated the loss of smell as a sign of civilization! Horowitz combines the expertise of a scientist with an easy, lively writing style. She describes her own cognitive testing of dogs, such as verification of the claim that they know the time their owners will come home. The author doesn't think there is any magic to this ability, and proposes that it has to do with the amount of time their owners' smell lingers. When fresh owner smell was introduced in the house, the tested dogs reset their "clocks" and failed to wait at the appropriate time by the door. The author writes mostly about the wonders of the nose, giving as much attention to the human one as that of the dog. Our noses have millions fewer olfactory receptors, and many fewer kinds of receptors, while we are unable to detect pheromones because of the lack of a vomeronasal organ. This is why dogs are called macrosmatic, whereas we are only microsmatic, or "feeble scented." But perhaps this is not fair to our species. The author goes out of her way to show that given training, a different attitude and closeness to the source (bending down to the ground or a fence pole), humans can sniff out lots of interesting things. We have no trouble picking out someone who had a garlic-heavy meal the day before, and nonsmokers surely don't need to see someone with a cigarette to know if he or she is a smoker. Despite all this olfactory acuity, however, we remain intensely visual creatures. White wine colored red fools even the connoisseur, who tastes it as red because vision almost always wins the battle of human perception. Dogs are obedient, eager to please and highly trainable, which is why they do all kinds of jobs for us. In comparison, the cat presents an enigma worthy of the wonder and awe that is the theme of Abigail Tucker's "The Lion in the Living Room." What do cats do for us? They sit pretty, purr when petted and seem to use us instead of us using them. How come we like them so much? One possible answer is Konrad Lorenz's so-called Kindchenschema (infant-appeal) according to which we fall for signals of vulnerability in the young of our own and other species. With its relatively large frontal eyes and rounded features, the house cat sends many of these signals. They arouse human care and protectiveness even for a species that massacres songbirds and poses other environmental threats. Another possible explanation is that we began to love cats for precisely these predatory capacities, tolerating them in order to keep mice and other rodents away from our homes and food storage. This may be the main reason the Near Eastern type of Felis sylvestris (cat of the woods) was turned into Felis domesticus about 12,000 years ago. Although the cat's body changed remarkably little, its character became quite a bit more tolerable than the way Frances Pitt, a wildlife photographer, once described a wildcat she owned, which "spat and scratched in fiercest resentment. Her pale green eyes glared savage hatred at human beings, and all attempts to establish friendly relations with her failed." Tucker describes the history of the cat's domestication, its relatively small breed differentiation (compared with dogs), while reviewing feline traits that we like, or think we like. Cats are depicted as protein-oriented hypercarnivores, which know how to manipulate us with well-timed meows and purrs while loathing members of their own kind. But although the latter view is popular, is it really correct? Having had multiple cats in my home all my life, I'd say it is true for only half of them. These cats would indeed have been perfectly happy without feline company. But the other half actively sought out the company and affection of humans and that of other cats, snuggling with their friends every day. Cats may search for a companion when he or she is gone, or cease eating upon the death of another. They can be quite a bit more social than they're given credit for. Nevertheless, we like the image of cats as independent and territorial, as masters over us slaves, which view is enshrined in our internet heroes, from Henri, the blasé French-speaking aristocat, to Grumpy Cat. They all exude nonchalant perfection. With informative first-person excursions to different places and topics, Tucker reviews all aspects of our favorite pet as well as the spell it has cast on us. The only problem I have with both books is the mismatch between titles and content. Horowitz's title suggests it is about being a dog, but the subtitle better covers her theme. Her book is about the olfactory sense, its huge importance for the dog but also its overlooked role for ourselves. Tucker's title suggests we will hear about the sweet-looking carnivore in our living room, but instead of telling us how cats behave and why - which has been done many times before - she relates where cats come from, why they may have been domesticated and why we hold them so dear. We are a pet-loving species, even more so in our modern urban lives than before, which is why we like to read up on our furry companions while they purr in our laps or snore at our feet. Dogs and cats have more in common than people assume - they're predators, after all. FRANS DE WAAL is a primatologist, a professor of psychology at Emory University and the author of "Are We Smart Enough to Know How Smart Animals Are?"