between two walls that are two meters apart
from each other. While you are trying to find out
how, let us explain how a species of garden spider
has solved this problem.
Garden spiders sometimes spin their web between two distant branches.
Since such webs are quite large, they are ideal for catching prey.
Nevertheless, their large size results in a gradual decrease in the tautness of
the web, which means a decrease in the ability to catch prey. So spiders
need a solution to this. You might have thought that the spider would spin
a new web once the web is not taut enough any more. But instead of re-
placing the web the spider does something amazing: It secretes a thread
from the center of the web down to the ground, and fixes a small stone on
to that end of the thread which is close to ground. Returning to the web
and pulling the thread, it lifts the stone. Then it fastens the thread, at one
end of which the stone swings in the air, once again on the centre of the
web. Consequently, the web is tightened up again as the weight of the
stone hanging from the web stretches it down.
You would probably not come up with such a solution,
and neither would many people with no knowledge of
construction techniques. Spiders, however, know and
apply this technique. How does a spider know such an
admirable technique and apply it so well? Moreover,
every spider for millions of years has spun its web apply-
W O N D E R F U L C R E A T U R E S
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