KROCHMAL, A.R.; University of Houston – Downtown: There�s no such thing as a free lunch: on the adaptive value of scavenging in snakes

Snakes are generally considered consummate predators, and therefore, scavenging by snakes has traditionally been discounted or ignored. However, recent reviews, combined with the ubiquitous observation that captive snakes regularly feed on carrion, indicate that snakes have a high propensity for scavenging. Documented episodes of scavenging by snakes have been touted as opportunistic events, but empirical investigations have shown that some species prefer carrion over live prey and that certain snake species consume either primarily or exclusively carrion. It therefore holds that there may be advantages to exploiting carrion as a food source which extend beyond energetic considerations. For example, snakes feeding on carrion might exhibit higher digestive rates and / or digestive efficiencies than do snakes consuming fresh prey items. Similarly, scavenging snakes might have a reduced basking time relative to snakes feeding on live prey items, and thus a reduced risk of predation. Finally, feeding on carrion might reduce the specific dynamic action of a snake, the spike in metabolic rate which follows feeding. To document and quantify the adaptive value of scavenging in snakes, I measured the digestive rate, digestive efficiency, basking time, and specific dynamic action of snakes relative to prey type (carrion vs. live prey). Findings will be discussed in light of the current utility of scavenging and will shed light on the initial adaptive force which drove the evolution of carrion feeding in snakes.