It depends on where the "different behavior" originates from, but in the case of traits like olfactory acuity that probably have a large genetic component, it's

It depends on where the "different behavior" originates from, but in the case of traits like olfactory acuity that probably have a large genetic component, it's related to the general idea of http://en.wikipedia.org/wiki/Genetic_diversity http://en.wikipedia.org/wiki/Genetic_diversity. I am also reminded of http://en.wikipedia.org/wiki/Fisher%27s_fundamental_theorem_of_natural_selection http://en.wikipedia.org/wiki/Fisher%27s_fundamental_theorem_....