_Defense, and Escape_
The behavior patterns that are associated with defense and escape in
snakes are widespread. The common racer is typical of the more
generalized snakes. Almost all elements of the racer's behavior are
found in snakes of other genera and perhaps, of other families. The
racer differs from these only in minor details of its behavior, in the
circumstances under which various behavioral traits are elicited, and
their relative importance. The common racer is one of the swiftest of
North American snakes, and it usually depends upon speed to avoid
enemies. Racers crossing roads may detect approaching automobiles at a
distance, and thereby may be stimulated to accelerate their movements
and so escape onto the shoulders rather than becoming traffic
casualties as many individuals of most other kinds of snakes do under
the same circumstances. The chances of such escape are of course much
better on dirt roads that are relatively narrow and have a rough
surface permitting efficient traction, than on wide smooth, paved
highways. The snakes are somewhat reluctant to venture onto open
expanses of pavement.