Large animals need more food than smaller animals, and their size restricts
where they can go to find it. Both factors determine not only where large
animals are found in nature, but also how much they are affected by human
activity such as deforestation.
A small animal needs a small amount of
food, and it can usually find it in a fairly limited area. Thus, a given patch
of forest can support many raccoons, but might only provide enough resources for
one or two bears. An average black bear may need as much as one hundred times
the space required by a raccoon. When a forest is disrupted — by the building of
a highway through it, for example — small forest dwellers may cope with the
change fairly readily, but a larger animal may find itself confined to only a
fraction of its former range, too small a space to sustain it.
While
being large reduces the danger from predators, it also poses challenges in
getting around — a big creature might have trouble moving through the dense
undergrowth of a forest, for instance. Thus, kodiak and polar bears tend to live
in open environments, while the smaller black bear, though it prefers forests,
can live in either. In western North America, as formerly open spaces have been
divided up for agriculture and pastures, the brown bears who once lived there
have disappeared, and the smaller black bears have replaced them. If these areas
continue to be developed, however, we can expect that the black bears will
eventually be squeezed out as well.
Animals have always occupied a prominent position in the human imagination. They
figure in our traditions, in our religions, and in the stories we tell each
other. The relationships of animals to each other and to their environment give
us something to compare ourselves to. This, in turn, provides us with a
framework for describing our relations to each other; animals are thus, in the
words of Claude Levi-Strauss, “good to think.” By examining and understanding
the different ways we talk about animals, we can begin to learn how we think
about ourselves.
In Western civilizations, for example, people have
historically drawn a sharp distinction between themselves and the animal
kingdom. As a result, Western gods take human form; also, people are thought to
have souls and afterlives, while animals do not. In the belief systems of
non-Western civilizations, however, animals, like people, often have afterlives
and appear as gods as well.
Totemism, which involves a mystical
relationship between a group of people and one or more species of animal, is one
particular way animals take on spiritual significance in human culture. The
animal (or animals) can be considered either an ancestor of the human lineage,
that at some point changed from animal to human form, or simply as a disguise
for a mythical culture hero. In totemistic belief, human society is just one of
the many animal societies that share the world; accordingly, an injury to a
totemic animal is frequently a crime, like the injury of a human.
In general, large animals tend to grow slowly, live a long time, and have few
offspring compared to smaller animals. Large-bodied animals also tend to evolve
in fairly stable environments. Why is this? In a stable environment, newborns
have a relatively good chance of surviving to adulthood; consequently, parents
tend to have few offspring and invest extensive amounts of time and energy in
them. Additionally, these offspring usually have long growth periods and end up
larger. By contrast, smaller animals often have many offspring, and invest
little effort in any one individual.
Most of the creatures in Large As
Life follow the large animal pattern, especially the bears, the cats, and the
rhino. For instance, among the big cats, litters of more than a half dozen are
rare. The squid is a notable rulebreaker, in that it lays millions of eggs at a
time, of which only a handful live long enough to reproduce. And while adult
cats will care for their cubs as they grow, baby squid have to make it on their
own.
In addition to limiting where it can live, an animal’s body size
affects its susceptibility to ecological disturbances. For large animals, to
which only a few young are born every year, an abrupt change, such as an
environmental shift or the intrusion of humans, can easily eliminate a whole
generation at a time. Moreover, once a population crash occurs, animals that
give birth to many offspring will be able to recover quickly, while large
animals, with their small litter sizes and slow maturation rates, can only
rebuild their population slowly, if at all.
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