Berkley Tacklebox: Why Do Bass Eat Plastic Worms?

Having a curious mind can have its drawbacks. For me it's a particular nuisance when I'm fishing trying to focus on the task at hand.

Having a curious mind can have its drawbacks. For me it's a particular nuisance when I'm fishing trying to focus on the task at hand. One minute I'll be casting to a log, intent on retrieving my lure, and before I know it the bait is sitting still while my mind races off reflecting on life's great mysteries.

 Like, why are fathead minnows called fatheads? They don't seem unusually fat around the heads to me. Or why aren't spinnerbaits called whirley-gigs? Wouldn't that be catchier? Or why do bass strike at plastic worms?

 For the life of me I couldn't figure out why bass would strike at anything remotely similar to a long slimy worm.

 To say that bass strike plastic worms because they resemble a natural food source suggests that bass think as humans, that they follow some sort of reasoning which goes something like, "I'm a bass. Bass eat worms. That's a worm. Let's eat!"

 But bass don't think like humans. They don't see what we see, hear what we hear, smell what we smell, feel what we feel, much less think what we think. If they reason at all it is highly unlikely they reason as we do. They have their own mental equipment, not ours. So any interpretation of bass behavior should shy away from shrouding bass in human characteristics.

Second, contrary to popular opinion, bass really don't eat worms — at least not very often. It's not that bass wouldn't eat them if given the chance, it's that worms aren't generally available.

 Worms and nightcrawlers are terrestrial animals not aquatic ones. For the most part they spend their lives burrowing through the soil. As fairly lousy swimmers they understandably don't make a point of frequenting the local swimming hole. A bass could go through its entire life without ever seeing one.

 In a series of tests at the Berkley Fish Research Center we took medium-sized largemouth bass which had been reared in farm ponds using only formulated hatchery feed as food and presented them with soft plastic cylinders. We reasoned that since the fish had never seen natural prey on any sort, if bass lure selection was based largely on past experience, then these naïve bass should not be predisposed to strike one lure more than another. To them, one piece of plastic should be about as good as the other.

But the bass didn't see it that way showing very little interest, even when the plastic pieces were tantilizingly close.

 However, when the bass were shown long worm-like cylinders the attacks were far more frequent and stronger, regardless of whether the lures were trolled, jigged or whatever.

 In other words, the worm-shaped plastic cylinders were ten times more effective than the cubic chunks of plastic, even on bass that had never before seen worms of any sort — real or not.

 Relying on worm shapes to release prey-striking behavior makes a lot sense for toads or birds, which in fact eat worms frequently. But for bass it doesn't make much sense at all.

 Which brings us back to the original question — why do bass strike at plastic worms? Admittedly, I'm stumped. But I intend on getting back out on the water, making a few casts, and letting my mind drift off to further reflect on life's great mysteries.