Prey

Adult largemouth bass most commonly feed on a wide array of fish, notably gizzard and threadfin shad in temperate or southern waters where they occur, and shiners, small sunfish, yellow perch, silversides, and alewives in other waters. They also favor the many species of crayfish that occupy nearly all bass waters of North and Central America. Though not particularly nutritious from a caloric standpoint, crayfish are relatively easy to capture, despite their imposing claws, which probably accounts for their prevalence in the diet of bass continentwide.

Less common prey include small ducks, snakes, mice, frogs, and salamanders. Studies show that young bass quickly learn to leave turtles alone, for the reptiles scratch and claw their mouths and throats, causing the fish to spit them out. Bass also ignore bullfrog tadpoles because of toxins in their skin.

Bass may try to eat prey almost as large as themselves, or they may settle for the larger forms of tiny zooplankton. The lower limit of prey seems determined by several factors. Prey must be large enough to be visible and worth chasing. Bass rarely waste more energy chasing food than they get from digesting it, but large mouthfuls of tiny prey may be nutritionally advantageous at times.

The upper limit of prey size is determined by the gape of the mouth and throat and the ability to catch and hold strong, struggling prey. Bass readily eat thin preyfish like shiners or shad in longer sizes than thicker sunfish. Adult bass occasionally eat prey up to 60 percent of their own length. Typically, however, they eat prey between 10 and 50 percent of their own length, as shown by stomach samples. The most common range of prey size is 20 to 40 percent. Fish of this size offer the best balance between energy needed to capture them and energy gained from eating them.

Common prey in a body of water are, of course, some of the most important guides to lure and livebait selection. Successful bass anglers match crankbaits, spinnerbaits, and even jigs to colors of preyfish and crayfish, particularly in clear water. Topwater lures appeal to the largemouth’s generalist attitude. Any crippled-looking creature on the surface is fair game if it fits into that expansive maw.

At times, seasonal movements of prey can make bass highly selective in their feeding.