This is a pretty cool article, although I'd like to see the actual paper.
Competition among males is often expressed in the form of elaborate weapons made of bone, horn or chitin. The weapons often start off small and then, under the pressure of competition, may evolve to attain gigantic proportions.
The underlying message being that bigger weapons are more intimidating, and therefor require less use. If, as a male, you spend less energy on defending your territory, you have more available for procreation. That, and injuries in the animal kingdom are often fatal, either directly or indirectly. It's best to avoid the fight in the first place.
Sexual selection was Darwin’s solution to a problem posed by the cumbersome weapons sported by many species, and the baroque ornaments developed by others. They seemed positive handicaps in the struggle for survival, and therefore contrary to his theory of natural selection. To account for these extravagances, Darwin proposed that both armaments and ornaments must have been shaped by competition for mates.
Darwin's concepts of sexual selection have been expanded upon, of course, but the basic idea holds true. Nothing with an energy cost fails to have a purpose... and realistically, that purpose should end up in a net energetic savings (active biological use of energy, not an entropic sense).
The article goes on to discuss the process of turning harmful weapons into display weapons, and the gradual adjustment from one to another. Many organisms (crabs are cited) have weapons that are used for both purposes. Humans, who's weapons are manufactured rather than genetically inbuilt (memetically coded weapons?)have only recently developed them for display rather than potential use. With the exception of their initial use at Hiroshima and Nagasaki, this is a solid explanation for the existence and lack of use of atomic arms. Humans would prefer to explain this by rationalising that "we knew what the outcome would be", which is understandable... if you fail to account for all the other horrible weapons we have developed for which we also know the outcomes (VX and Tabun Gas, anyone?). Once we're able to demonstrate that we have the ability to use such a display weapon, it is no longer necessary to put it to use... the people/organism with the best ritualised bluster wins (see Cuban Missle Crisis).