is quite conceivable that early animals were
divided in the matter; that the impulse of some was to escape from
danger, while others, frightened by the presence of the enemy,
remained absolutely still. Each plan has succeeded. Those which, on
running, ran fast enough to escape became the parents of others like
themselves, led eventually to a line of animals in whose speed lay
their safety. Those, however, which attempted to escape, and failed
because they were not swift enough, had their line cut off, and were
thus less likely to be represented in the following generation. The
constant result of errors along this line would be to destroy the slow
and preserve the swift, and in the course of time it is quite
thinkable that only the swift should remain. As the movements grew
more and more keen, even the slower of these would pass out, thus
tending always to produce the succeeding generation from those who
were most rapid, and hence most likely to transfer to their children a
similar power.

But there is another tendency of animals which leads them when
frightened by their enemies to remain quiet. If this impulse is obeyed
thoroughly enough, it is easy to see how the owner of this habit might
entirely escape detection by his enemy. Any restless animal unable to
restrain his nervous agitation naturally betrays his presence and is
picked off. The result of evolution along this line would be the exact
reverse of the preceding. Those that lay most absolutely quiet would
be the parents of succeeding generations, while those who were slow in
coming to rest, or were indifferent about remaining quiet, were picked
off, and their tendency eliminated from the future of the species. In
this way many animals have come to keep entirely quiet in the presence
of danger. It is not a sign of high intelligence. As a matter of fact,
it is rather a stupid procedure, so far as the animal itself is
concerned, but it is a preserving stupidity, and many animals have it.

The "June Bug" (which is not a bug, but a beetle, and arrives in May)
has this interesting habit of keeping quiet. If in its flight it
strikes the globe of an electric light, it falls at once to the
ground, and remains perfectly quiet for a time. After a short interval
it recovers and starts out to regain its previous activity. But this
recovery is by slow stages, and the whole procedure on its part looks
exceedingly stupid.

The little snake with flattened and expanded head, k