The mangrove salt marsh snake (Nerodia clarkii compressicauda Baird and Girard) may experience varying levels of foraging success because the prop roots of the red mangrove (Rhizophora mangle L.) have a six-fold variation in density. Adult female N. c. compressicauda were allowed to forage for 24 h on a known density of prey in an enclosed habitat simulating one of four experimental prop root densities. Snake behaviors were recorded during the first hour of each trial, and the number of prey ingested was determined at the conclusion of the trial period. Individuals had the greatest success at the root density most often encountered in their habitat. More time was spent in the water than atop roots; but individuals were less likely to forage in the water at low root densities, suggesting that they, like their prey, may be afforded protection from avian and mammalian predation by the mangrove forest canopy. Mangrove salt marsh snakes spent the majority of time resting motionless and appeared to be opportunistic predators, attempting to ingest prey only during chance encounters.