  Recently, different dispersion strategies in population models subject to
geometric catastrophes have been considered as strategies to improve the chance
of po\-pu\-lation's survival. Such dispersion strategies have been contrasted
with the strategy where there is no dispersion, comparing the probabilities of
survival. In this article, we contrast survival strategies when extinction
occurs almost surely, evaluating which strategy prolongs population's life
span. Our results allow one to analyze what is the best strategy for survival
based on parameters as the probability that each individual exposed to
catastrophe survives, the growth rate of the colony, the type of dispersion and
the spatial restrictions.
