Nose Knowledge - What the Dog Knows - page 20

ceptor, it fires an olfactory neuron. Bam. That is not the only theory out there, but it's the
reigning one. You would think that researchers would be further along in understanding this
particular sense, but amid the general devaluing of the sense of smell in the Western world,
the chemical complexity of odors, and the complexity of the neural circuitry that underlies
even the act of sniffing, they have a ways to go.
As for comparing one nose with another? Neurobiologists aren't that interested in setting
up olfaction competitions between species. They don't care which species' nose is “the best.”
What does that mean, in any case? This kind of speculation is better left to Animal Planet's
Creature Countdowns , featuring the “Top 10 Animal Troublemakers” and “Top 10 Animal
Skills.” The bloodhound made number nine on that last list, with a sense of smell so fine,
according to the producers, that it is “up to a million times more sensitive than that of hu-
mans.” I am not making this up. Animal Planet is.
Some species' noses do rise above the rest, literally and figuratively. I bet if we could train
bears to track, their noses would confer real bragging rights. Biologists believe that grizzly
bears generally have a much better sense of smell than any dog. Bears' noses get less press than
dogs' for all the obvious reasons. If you ever get the chance to stare at a grizzly's nose close up,
you can see what a stunning instrument it is—tilted up at the end, with huge flaring nostrils.
If you are at exactly the right angle, you can see through that nostril space to the blue sky
beyond. The grizzly bear can manipulate her nose like a flautist can flex her fingers. If you
could peer inside her horribilis skull at the nasal cavity, you would see delicate structures that
look like two huge morel mushrooms or rounded honeycombs planted side by side. Their job
is to process scent. How well? Pretty darn well. For miles, it's estimated.
But maybe not for miles and miles and miles. Nonetheless, Animal Planet, some topics,
and a number of bear websites use the following phrase: “Some scientists say bears can smell
carrion from up to 18 miles (29 kilometers) away.” It's rather odd, I thought, that “some
scientists” would all agree on such a specific bear mileage. The figure's genesis, I discovered,
was one 1976 bear-conference paper noting that one radio-tracked bear traveled twenty-nine
kilometers with some speed and ended up at a carcass. The ecologist, Frank Craighead, stip-
ulated, “It was not determined just when and how the carcass was detected.”
Nor are there good comparative studies about the capacities of one animal's nose versus
another, said Larry Meyers of Auburn University College of Veterinary Medicine. Repeat
falsehoods enough, though, and they don't just take on the patina of truth, they become its
replacement. Bears don't care, and inventions about their olfactory capacity probably matter
less because bear handlers don't end up testifying in criminal court about their abilities. Nor
are bears' noses depended on for finding lost children alive.
Besides, there's just no great bear-nose grant money these days. The same isn't true for re-
search on human noses. We're always interested in ourselves, and it's easier and safer to get