The Critter Connection to Largemouth Bass
August 28, 2019
As suggested by their name, largemouth bass have been known for mouth size and what they can cram into it. Dozens of scientific studies describe the diet of this species. They’ve been conducted to describe its life history in various waters; to asses its level of competition with other species; effects on populations of preyfish; suitability for stocking in new waters; and its threat to endangered and threatened species.
The bass’ large mouth is ideal for feeding on preyfish that live throughout the water column. They use a variety of feeding tactics to engulf or overtake prey, or to pin them to the bottom. Over the years, biologists have documented more than 60 different preyfish from bass stomachs, but that’s surely a low estimate, as most waters remain unstudied, and the remains of small fish are quickly digested and become indistinguishable. But as we know, bass aren’t picky; they also consume a variety of aquatic creatures.
As far back as the mid-1950s, researchers studied the size of prey bass could consume, examining both the length and body depth of different types of preyfish. They found that a bass’ mouth gape limits what it can stuff down. It was obvious that bass could eat more slender prey and those without spines of greater length than broad fish with spines, such as sunfish and tilapia.
Bass could successfully engulf sunfish up to about one-third of their length, tadpoles to 40 percent, and perch about half their length. But these lengths represented maximums, and observers noted that bass most commonly ate far smaller prey, which typically are more abundant.
On the other hand, a study in Arizona found that bass had a hard time distinguishing prey that were too large to safely consume. It was initiated by reports of bass in reservoirs choking to death with large tilapia lodged in their throats. I’ve observed this as well in Mexican reservoirs where lunker bass rely on tilapia as well as shad. I’ve seen fish over 8 or 9 pounds, dead or struggling to survive on the surface, a tilapia lodged in their gullet, still alive. Occasionally, predator and prey can be separated and they survive the encounter, but bass usually are morbid.
Researchers found that bass would ingest bluegills and tilapia that exceeded the width of their gapes. When the dorsal spines lodged against a bass’ jaws, it choked. Bass would choke and cough, sometimes dislodging the preyfish. But the team found that bass didn’t learn from this lesson and would attack another excessively large preyfish soon after their first encounter, with the same result.
We know that bass are quick to learn to avoid unfamiliar items that they chase and strike, but prove fake, such as crankbaits. Experiments indicate that captive bass become progressively less interested in lures, finally ignoring them. But it seems impossible for bass to “learn” not to eat what are normally preferred prey, even if they’re too big to be eaten.
The Crayfish Connection
In many areas, crayfish are common prey, and bass sometimes eat craws up to one-third of their own length, though they typically eat far smaller ones. In diet studies, researchers have found crayfish comprising up to 60 percent by weight of bass stomach contents in waterways without shad. Fish nutritionists have wondered about this food choice, as 50 percent of the dry weight of a craw is inorganic salts and chitin, substances not digestible by fish. They’re not energetically beneficial, compared to fish or other macroinvertebrates like larval insects. And their potentially large size, defensive behavior, and armament make them imposing prey.
Recent research in Wisconsin has found a seasonal shift in crayfish consumption. Dr. Daniel Isermann of the University of Wisconsin at Stevens Point reports that craws form a larger part of the diet early in the year there. “In one of our study lakes, crayfish constituted 80 percent of bass prey in June, 40 percent in July, and they continued to decline in importance into fall,” he says. “But we see a lot of variation among lakes. Overall, crayfish are one of the three key items in bass diets in this area, along with bluegills and yellow perch.”
Texas-rigged crawbaits have been a staple for decades, beginning with Hale’s Craw Worm, designed by Robert Hale of East Texas, then Gene Larew’s Salt Craw, which started the salt craze in softbaits. Today we find an array of crawbaits that rival the 340 species that inhabit U.S. waters, some with realistic claws and some with flattened claws that flap when pulled, adding vibration to the presentation. They’re great as jig trailers or fished Texas-rigged. Craw shapes and colors have been prevalent in hardbaits as well.
But bass don’t stop there. Less common prey include most of the animal kingdom: mollusks, insects, amphibians, reptiles, birds, and mammals.
One of the iconic sights of summer is watching bass leap to intercept dragonflies that buzz above and occasionally dip down to the surface. They usually miss the bugs, but score often enough to inspire them to perform acrobatic leaps. Nature photographer Albert Lavallee has published a fascinating set of shots from Oklahoma, showing largemouths leaping to eat mating green darners and black saddleback dragonflies, species endemic to that region. According to Lavallee, bass select flies that are paired up in their mating ritual, as the two connected flies are much slower, and twice as nutritious.
While most bug chasers are small, I’ve watched some bass in the 2- to 3-pound class doing the same thing. At times, I’ve been able to convince them to strike a weedless frog around lily pads where they often chase dragonflies. Bass are picky in this situation, however, seemingly focused on flies. Their ability to aim their jump from under water to catch an insect flying in air is remarkable, given the refraction issues that distort vision from one medium to another.
Adult bass also feed on large insect larvae that live on the bottom, notably the hellgrammite, a larval dobsonfly that reaches 4 inches and inhabits flowing waters with gravelly substrate. Young bass eat a variety of small larval insects that trout also favor. They’re all nutritious and rather easy to catch and digest.
Insect lures are available, but not many. Lunkerhunt’s Dragonfly is a recent entry in this category, built of a buoyant, tough material that can be Texas-rigged. It comes in six colors and floats a large offset-shank hook. It’s best cast on stout spinning tackle with braided line. Lunkerhunt offers the Yappa Bug, a 23/4-inch waterbug look-a-like with a Jitterbug-style lip to make it waddle slowly across the surface or pivot back and forth in walk-the-dog fashion. It weighs 3/4 ounce for long casts and is armed with a double hook that rides below the abdomen, weedless frog-style.
Megabass’ Grand Siglett (23/4 inches, 1/4 ounce) is another novel bug bait, modeled after a large cicada. It has a pair on hinged wings that fold close for easy casting but flip outward when the retrieve starts, giving it a gurgling, wobbling action, in the style of Heddon’s Crazy Crawler. Its motion activates a rattle chamber in the abdomen, designed to emulate the persistent buzzing of cicadas on a summer day.
Frogs are a bass feast as they coexist in warm swampy waters across their range. Diet studies show several species to be occasional prey in both the adult and larval tadpole stage. Experiments with tadpoles demonstrate that bullfrog tadpoles have an unpleasant flavor. Bass offered nothing else eventually eat them after spitting them out, but don’t eat enough to grow. They eagerly eat tadpoles of other species, however. Adult toads also seem toxic to fish, as they are to birds and mammals, and are rarely found in bass stomachs.
In recent decades, artificial frogs have dominated the softbait scene. From Snag-Proof’s Original weedless frog and Southern Lures’ Scum Frog, dozens of models are available, with new species discovered all the time. Most have a double-hook that allows it to fish over and through thick vegetation where they’re deadly. But they’re versatile, effective skipped under docks or fished across open water.
One new option is Hale-Stanley’s Sidetrac Mud Puppy, a 6-inch thick-bodied stickworm. Its has an “Action Maker” designed by Robert Hale. This tab allows an angler to fish the lure to run to the right or left, depending on how it’s rigged. With the lure on the left side of the hook shank, it runs right. This allows it to run on either side or underneath docks, fallen trees, stumps, and other cover.
In this category, I include so-called lizards, that popular and effective softbait shape. Whoever named them had an erroneous idea of bass diets, as I’m yet to find a reference to a lizard in a bass stomach. It’s certainly possible, as lizards lean to sip water from ponds and could slip. But this lure shape is surely meant to imitate a salamander instead. Most of the many salamander species are vulnerable in their aquatic larval stage, such as the “waterdog,” the gilled larval form of the tiger salamander. Adult newts are primarily aquatic and are eagerly eaten by bass that enter their swampy habitat.
In 1973, researchers at The University of Nevada, Las Vegas, found waterdogs the favorite livebait of anglers along the Colorado River. In diet tests, the meaty critters came out near the top of the favored food list for bass, preferred over golden shiners, goldfish, and other baitfish. In the late 1980s, the In-Fisherman staff found an importer of waterdogs and fished them in Minnesota lakes. Largemouth bass, along with walleyes, and pike couldn’t resist them, fished weightless on a weedless hook, or weighted. As I recall, they’d outfish nearly any artificial lure. Similarly, anglers at Lake Fork in Texas began fishing waterdogs and found them exceedingly effective for lunkers, so much so that a groundswell of opposition to the use of waterdogs arose, based on the assumption that many bass would be gut-hooked and die after release. In recent years, bans on livebait transfer among states have greatly limited their availability.
The Bird Bite
As omnivorous predators, bass are known to occasionally eat birds. They’re not common prey for obvious reasons—wings bring mobility in a different dimension. But there’s no denying the fascination of bass with birds.
Years ago when I lived in Massachusetts, I watched an adult red-winged blackbird seemingly taunt a lunker bass from its perch on a stand of cattails. The bird purposefully swooped down and fluttered just above the surface, as a bass that looked about six pounds rushed to the surface to try and intercept it. After the commotion settled, the bird did it again and again, until the bass lost interest or swam off. More often, bass consume more helpless prey, such as fuzzy ducklings following their mother across shallow bays, or fledgling birds that fall out of nearshore nests.
At the 2015 Bassmaster Elite tournament at Lake Havasu in Arizona in May, Aaron Martens came upon a bird-bite pattern and used as the basis of his victory there.
“I was way up shallow flipping large expanses of tules,” he reported. “Red-winged blackbirds had built nests among the stalks. While I never saw a bass eat a baby bird, I did catch one with feathers in its mouth, and found feathers in the livewell at the end of the day.” Though they were focused on red/black targets, the bass weren’t picky. Martens caught them on Texas-rigged green-pumpkin crawbaits with 1/2- and 3/4-ounce weights to penetrate the thick vertical vegetation.
Two years ago, I was fishing a local lake with a buddy in early summer and skipped a jig beneath a boat dock. I hooked and landed a beautiful fish around 41/2 pounds. While unhooking it, I noticed a bill extending from the bass’ esophagus. At first I thought it had eaten a pike, but upon further inspection, it was the bill of a small duck, not a hatchling but closer to half-grown.
Luremakers have responded with lures to imitate bird prey in shape and color. Persuader has a set of wooden Baby Ducks colored like different species and Savage Gear, a leader in making lures to imitate unusual prey, made waves with the 3D Suicide Duck, which won Best of Show in the Hardbait category at the 2016 ICAST Show. The lifelike 6-inch topwater sports a pair of paddling feet that buzz as it’s retrieved. Its treble hooks are adorned with yellowish duck feathers as well. Several companies offer topwater lures with bird coloration as well.
In the 1881 classic, Book of the Black Bass, Dr. James Henshall shares the account of a fellow naturalist who witnessed two largemouth bass simultaneously attempting to eat a snake that had been swimming across a pool in a creek in Iowa. A bass initially attacked it, swallowing the head region, when a smaller bass seized the tail end and began ingesting it, coming closer to the other bass. They reportedly engaged in this tug-o-war for some time.
There are a few references to snakes as bass prey in more recent literature. Texas biologists reported an 18-inch water snake in a 12-inch bass. The late Doug Hannon was a believer in the appeal of snakes to big bass, and he contributed to the design of Norman’s Snatrix worm, a 7- or 9-incher that was tightly curled so it would swim in snakelike fashion when retrieved. He later marketed a kit with big snakelike worms with the rigging essentials to bring them to life.
The latest snake bait is Hale-Stanley’s Sidetrac Cobra, a thick-bodied stickworm with the company’s Sidetrac system that allows anglers to rig it to run to either side of an object or rise or dive, depending on where the “Action Maker” is positioned on the hook.
Over the years, hatchling turtles have been found in bass stomachs, but further investigations led researchers to believe most were eaten after they died or were moribund. Experiments showed that tiny turtles would bite and scratch the mouths of bass that swallowed them, eventually forcing the fish to spit them out. The bass would persist for a number of attacks, but with the turtles resisting strongly, bass eventually learned to ignore them. But that hasn’t kept a few manufacturers from offering turtle lures, including the Bombshell Turtle that was offered by several lure companies until it was discontinued.
Mammals are the least likely of bass prey. Aquatic critters typically are large: beavers, nutrias, otters, muskrats. Only newborns would be vulnerable, but they remain in nests or borrows until they’re considerably larger. Most small rodents typically don’t go too close to water, but even agile voles and mice sometimes misjudge their footing and tumble into a lake or pond. I’ve had two turn up in my livewell after tournaments, both mouselike rodents.
Indiana biologist Jeremy Price was electrofishing and collected a 131/2-inch bass and noticed its bulging gut. When Price looked down its gullet, he was amazed to see the pointed nose and massive front claws of an eastern mole that apparently wandered off the bank.
Despite the infrequency of mammals in bass diets, mammal-imitating lures are widely known. In 1929, Heddon’s Meadow Mouse appeared, complete with leather eyes and tail, which became immediately popular, leading to a fur-finished model soon after, which sold for $1. It’s still a collector favorite.
At the 2011 ICAST Show, LiveTarget was awarded the award for Best in Show in the softbait category for their Hollow Body Field Mouse, a weedless lure styled like weedless frogs, but with a mousy shape and tail. It’s available in three lengths from 21/4 inches to 31/2 inches (3/8- to 3/4-ounce).
Another weedless model is Lunkerhunt’s Yappa Rat, a 23/4-inch surface bait with a double hook and Jitterbug-style mouth in the style of the Yappa Bug. It weighs 3/4 ounce to cast far and create a commotion in shallow slop habitat.
SPRO’s BBZ-1 Rat is a large surface or near-surface swimmer designed by California big bass expert Bill Siemantel. It’s jointed and sports a rubbery, replaceable tail. Four sizes run from 21/2 to 51/4 inches, weighing up to 21/4 ounces. They’re armed with a pair of extra-strong Gamakatsu hooks to handle the outsize bass that would be the most likely to feed on mammals.
While these attempts at realism fall far short of imitating the motions of these prey items, the lesson is that bass typically aren’t too picky about what they try to eat. If a lure’s in the right place and looking vulnerable, it may well get attacked. Note, too, that bass aren’t intimidated by large prey, even items too big to fit into their large mouths.
*In-Fisherman Field Editor Steve Quinn is a fishery scientist and bass expert who has written for In-Fisherman publications for over three decades.