While snake venoms are well characterized pharmacologically, the evolutionary history and functional utility of snake venoms has not been thoroughly investigated. Hypotheses advanced over the past hundred years suggest that snake venoms may increase evolutionary fitness by facilitating one or more of three functions; prey capture, defense, and digestion. This review provides a new approach to analyzing these hypotheses by reviewing patterns of venom enzyme activity from over one hundred species of venomous snakes. The patterns uncovered suggest that venoms found among the subfamilies, Elapinae, Viperinae, and Crotalinae do not statistically differ with regard to phospholipase A 2 , phosphomonoesterase, and phosphodiesterase activities. While this finding supports theories that venomous snakes may have evolved from a single common ancestor, viperine and crotaline venoms are shown to have proteolytic activities (e.g. L-amino acid oxidase, nonspecific endopeptidase, and trypsin-like activity) that are dramatically higher than elapine venoms. The proteolytic activities of venoms are significantly higher in the more recently derived crotalines, suggesting that the evolution of these venoms may be influenced by their digestive function. This review also introduces a novel index for comparing 'toxic risk', a measure that takes into account venom yield as well as toxicity. The results suggest that the toxic risk of these three subfamilies do not differ significantly despite their distinct evolutionary histories. This review also identifies taxa whose venom enzyme activities are dissimilar from their confamilials. Because of their unique venom properties, taxa whose venom greatly differs from their confamilials may prove useful for testing forthcoming hypotheses about the biological function and evolutionary history of snake venoms.