Big baits are all the rage on the bass cast-for-cash circuits. But recreational bass anglers more into catching than casting also have learned the merits of big lures — giant worms, super-size swimbaits, oversize crankbaits, 8-inch flutter spoons — for triggering bass bites.

And mid-summer on into the fall is the best time for these outsized lures. Here’s a little biology that goes along with the bigger-is-better trend.

Energy supply

Bass need energy to grow, and develop eggs and sperm to reproduce. The best way to gain energy is to swallow big prey.

A bass gets more energy from a 6-inch shad than a 2-inch shad. Assuming the larger shad are abundant and easily caught, bigger means more energy per bite.

And more energy per bite is especially important in the Deep South, where water temperatures climb into the high 80s and bass’ metabolic machinery burns a lot of energy. A bass has to consume more energy than it burns to grow.

I read a lot about downsizing baits when the bite is tough, like after a cold front or for heavily pressured bass. This works, at times; maybe bass like a snack now and then.

But you also hear a lot about “reaction bites” and “triggering bites.” A big, energy-rich meal that is in a bass’ face and easily captured is the “energy-smart” meal.

Yes, dainty “snack food” like drop-shots and shaky head finesse worms might be the best way to sack a limit on any given day. But from an energetic standpoint, always show bass big lures — even on tough-bite days.

Match the hatch

The concept of “search image” is a well-established principle in animal behavior, and it especially applies to fish. The principle predicts that a predator, when provided with an abundant food source, seeks forage — you might say, “locks on” — that matches the search image.

Search image can be a particular color pattern, the position in the water or a certain narrow size range.

Match-the-hatch is all about search images.

As summer advances, forage fish are growing. Yes, the young-of-the-year shad and sunfish might be only 2 to 3 inches long, but last year’s shad are now 6 to 8 inches and sunfish are 4 to 5 inches.

The bass can go tiny or they can go large; there is little in between. The energetically desirable search image is for something large.

Hooking up

Ever wonder how you can hook a bass on a 10- or 12-inch worm with the point of a 3/0 hook only 1 ½ to 2 inches from the front of the worm?

Six decades ago, J.M. Lawrence earned his doctorate in fisheries at Iowa State University studying feeding behavior of largemouth bass. Lawrence first observed that bass ingested fish head first.

When a bass caught a forage fish sideways or tail first, the fish was spit out and quickly ingested head first.

Smart bass: Forage fish swim better forward and are less likely to escape in reverse.

Also, headfirst down the throat is more streamlined and would “disarm” a prey’s anatomical defense mechanisms, like fin spines.

So you don’t need a ridiculously large hook on a giant worm — you just need one with a wide-enough gap so the bulk of the worm doesn’t interfere with the hook point sticking the bass. The same goes for a big swimbait.

If you think giant spoons don’t fit this model, think again. Supposedly, these spoons resemble shad. Typically, bass hit the spoon on the fall.

When a distressed shad is sinking to the bottom or diving to seek shelter, it does so nose first. The nose of the shad is the “blunt” end, and so is the bottom, hook-bearing end of the spoon.

The bass does not have to engulf that entire 8-inch spoon to the hook; it eats the spoon hook-end first. 

Note that “head first” doesn’t apply to crayfish. I’ve caught a lot of bass with crayfish claws visible in their gullet but never with a crayfish tail visible. Tail first definitely is a safer way to eat a crayfish.

So bass probably eat a jig with a big trailer by ingesting the jig first.

How big is too big

Having established that bass ingest forage fish head first, Iowa State University’s Lawrence learned largemouth bass could — and would — consume forage fish whose body depth was slightly greater than the bass’ mouth width.

Bass anglers don’t routinely measure bass’ mouth widths or lure widths, so let me put this in terms of bass and lure length.

As a rule of thumb, a largemouth can eat a slender-bodied forage fish like a shad (or a shiner, trout, blueback herring, or a swimbait) up to one half its length and a deep-bodied forage fish like sunfish up to one third its length.

A 3-pound largemouth can easily handle an 8-inch spoon or a 6-inch Bull Shad swimbait. 

Lawrence didn’t measure mouth widths of smallmouth bass, but I would “guesstimate” that a smallie can eat a slender-bodied prey up to a third its length and a deep-bodied prey up to a fourth its length. 

So bigger can be better, even on a tough bite day — and I doubt you have anything in your tackle box too big for a bass.