At least 79% of predaceous land-dwelling arthropods use extra-oral digestion (EOD) as a means of utilizing relatively large prey with intractable cuticles. Through the injection of potent hydrolytic enzymes, either by refluxing or nonrefluxing application, these predators greatly increase the efficiency of prey extraction and nutrient concentration. The advantages of EOD are expressed ecologically as an abbreviation of handling time and an increase in the nutrient density of consumed food, allowing small predators to consume relatively large prey. The basis of EOD is a highly coordinated combination of biochemical, morphological, and behavioral adaptations that vary with different taxa.