Intelligence is a valuable thing, but it is not usually the key to survival. Sheer fecundity ... usually counts. The intelligent gorilla doesn't do as well as the less intelligent but more-fecund rat, which doesn't do as well as the still-less-intelligent but still-more-fecund cockroach, which doesn't do as well as the minimally-intelligent but maximally-fecund bacterium.

We starve the rats, creosote the ticks, swat the flies, step on the cockroaches and poison the scales. Yet when these pests appear in human form we go paralytic.