The intensity of competition depends
upon the density of population. As the
population increases, relative to the
capacity of the environment, the competition
increases and, unlike predation.
cannot be diverted to other species. This
level of competition is inherent in the
psychology of the rats. Fortunately.
means to increase competition are readily
available in sanitation procedures.
Reduction of the food and harborage
increases competition and thereby decreases
the rat population. The important
point is that, in contrast to
predatory methods, sanitation is-feasible
on a scale that will reduce the rat population.
The biological principle governing
predation and competition is the
same but the practicabilities are greatly
different. Given our present conditions
as regards housing, human failings,
wages, etc., it is generally feasible to
increase competition btut rarely feasible
to increase predation.