Trout don't eat metal, plastic, feathers or fur, and in the spring they rarely see any animal that burrows into the ground.
Why then are countless trout caught on lures and baits that look nothing like anything that is alive in the water?
With the opening of trout season just days away, the answer to that timeless question lies in the angler's ability to adapt to conditions and present the unnatural object in ways that stimulate the trout's senses.
"That's why the better fishermen catch more fish," said Ed Vaccari of Tackle Unlimited in Jefferson Hills. "They change what they're doing with the changing water, and they know how to use their lures to attract trout."
Rooster Tail spinners have been catching trout since the 1950s. The Daredevil spoon has been considered a prime trout lure since the early 1900s. Nearly 2,000 years ago Roman scribe Claudius Aelianus wrote of Macedonian fly fishermen on the Astraeus River "[fastening] red ... wool round a hook, and [fitting] onto the wool two feathers which grow under a cock's wattles, and which in colour are like wax." And probably as long as humans have lived in temperate latitudes, the earthworm has been dug up for trout bait. But none of those things are a natural food source for trout.
The scientific community is undecided on exactly why trout, which can at times be so famously persnickety, will sometimes take baits that neither look, smell nor act like natural foods. There's likely more than one good reason.
If you ordered a steak and the waiter dropped a piece of Styrofoam on your plate, you wouldn't take a bite -- your visual, nasal, auditory and tactile senses would alert you that the object is not food.
In constant competition for moving food items, trout have very little time to decide what is and isn't food. Reacting in an instant, often to objects at a distance, trout senses appear to suggest general characteristics to the brain, not necessarily conclusive identifying data. Sometimes that information generates a vague curiosity, which might move the fish to nibble to determine whether that smelly thing is food. Other times the sensation sparks an instinct to strike, generating a savage attack on a sharp reflection of light.
Hatchery-raised trout, which have been eating food pellets throughout their one year of life, face a steep and serious learning curve when they're abruptly stocked in a lake or stream. Trout of different sizes and levels of experience respond differently to potential food sources, and with varying tolerances to water temperature, pollution and other variables, brook, brown and rainbow trout can react differently, as well.
The most effective baits and lures are those that simultaneously stimulate more than one sense.
In spring, when earthworms are still buried deep in the ground, it's rare that a worm gets washed into the water. When used as bait, trout get a whiff of the unnatural scent and approach to investigate.
"They feel the vibration from all that wiggling, and see it moving around. There's three senses stimulated -- they bite," said Vaccari. "Brown trout are the meat eaters; they go for worms. That's why those butter worms work so well. [The South American fly larvae] don't like water and they wiggle more."
There's nothing natural about smelly paste baits, but they catch fish. The scent, the colors (often fluorescents reflecting light in the ultra-violet range) and perhaps the motion as the gob hangs under a bobber bouncing on surface chop, stimulate multiple sense organs of a hungry trout.
Pressed baits include the scent of fish oil or ground marine-animal parts mixed with a plastic compound and shaped to cause vibrations in the water as they're retrieved. Sold in a variety of colors, they stimulate three senses.
Metallic spinner blades might suggest sharp flashes of light reflecting from the scales of a thrashing minnow. Rig the blade in front of a plastic or fur body in a variety of colors, and work it through riffles or in jerky motions through still water to stimulate several trout senses.
While many flies are tied to suggest the size, shape and color of natural food sources, many tiers include sparkle materials to reflect light. Some streamer and wet fly patterns include specific feathers that ripple in the water, causing vibration.
"Freshly stocked trout are not really familiar yet with what food sources are in the area," said Bob Shuey, owner of Neshannock Creek Fly Shop in Volant, Lawrence County. "They're used to eating pellets in the hatchery. I think early in the season flies tied to imitate an egg may look like a familiar pellet. More experienced trout can be more selective. They're focused on the real McCoy -- caddis, mayfly, stone fly, whatever."
Whether the bait is a fly, lure, paste or live bait, said Shuey, anglers should be aware of three things.
"Presentation, size and color," he said. "Using their variety of senses, that's what trout are looking for as they evaluate an object to determine if it's a food source."
Most important, be willing to adapt to conditions.
"What worked on Monday might not work today," said Shuey. "Changing conditions are changing the way the [bait or lure] impacts the trout's senses."