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Animal Noses
Nature Bulletin No. 729 October 26, 1963
Forest Preserve District of Cook County
Seymour Simon, President
Roberts Mann, Conservation Editor
ANIMAL NOSES
"Of all the animals, man has the poorest nose; he has virtually lost the
sense of smell". Like so many general statements, that remark by
Ernest Thompson Seton, the great naturalist, artist and storyteller,
should be taken with a grain of salt. Seton was speaking of mammals
only.
Modern man does have a sense of smell and in some individuals, such
as wine tasters, coffee tasters and perfumers, it is highly developed but,
in general, his nose is far inferior to the smellers of other mammals.
Nearly all of them have noses which provide the most acute and
discriminating of the five senses: smell, sight, hearing, touch and
taste. Among the few exceptions are the toothed whales, believed to
have no sense of smell at all.
There are other groups in the animal kingdom which apparently have
no sense of smell comparable to that of mammals. The lower
invertebrates have none. Birds, with few exceptions, have none.
Contrary to popular belief, vultures find their prey -- dead animals --
by means of their marvelous telescopic vision and not by any ability to
smell it. They commonly find carrion before it begins to rot and stink.
However, experiments have demonstrated that some seabirds -- petrels,
shearwaters, and the albatross --do have a well-developed sense of
smell; and that the kiwi, a queer humpbacked flightless bird in New
Zealand, finds its prey at night by means of its acute senses of smell
and hearing. There are slit-like sensitive nostrils near the end of the
long bill.
Many insects notably moths, some butterflies, honeybees and ants --
have an extraordinary sense of smell. Lacking any nose, they have
sensory organs located in the outer segments of their antennae or
"feelers". We know of an instance when the scent of a female Cecropia
moth, newly emerged from a cocoon in a cage within a greenhouse
where a few windows were partially open, attracted scores of males --
some of them from miles away. Bees in search of nectar are attracted
to flowers as much or more by their scent as by their color. Ants follow
odor trails made by co-workers. They live in a world of smells.
Fish
are commonly ranked among the supersmellers but most
scientists agree that, instead, they are supertasters. As explained in
Bulletin No. 270 (Smells and Smellers), smell and taste are closely
related chemical senses but odors come as minute particles in gaseous
form, whereas taste is a sensation produced by particles in a solution
such as water. Some fish have sense organs located from mouth to tail,
so that they literally taste with the whole body.
Having such poor noses ourselves and no other way of detecting or
measuring odors, it is difficult for us to appreciate how important --
how vital -- an acute sense of smell is to most wild four-footed
animals. By means of it they find their food, evade their enemies, find
others of their kind and find mates. For deer, rabbits and other
defenseless species it spells life or death. It enables an arctic hare to
survive by finding the tops of dwarf willows beneath several feet of
snow, or a squirrel to find acorns that he buried in autumn.
Much of what we know about animal noses has been learned by
observers and hunters of wildlife; also from dogs bred and trained to
trail and find certain kinds of game. A dog's sense of smell is as
marvelous as that of a wolf or an elephant. A 'coon hound, for
instance, knows when a raccoon's track was made, how fast it was
traveling, and in what direction. He will ignore the scent of a rabbit or
any other animal.
"Does it not betray itself by its odor?" (Cicero)
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