What a stickbait (senko) mimics and why it works

I’m actually not sure anyone knows exactly what a bass actually sees in a senko (stickbait) that makes it so incredibly enticing. Even Gary Yamamato himself.

But there is something about the slow fall of the big fat worm that just drives bass crazy. So it must mimic or do SOMETHING that makes them so interested.

In this article I’m going to lay out all of the theories of what a senko actually is imitating and what makes bass want to bite them when nothing else works. And if you haven’t used them yet, you need to!

How the senko was invented

First I have to explain how the senko was invented, as it was actually a mistake.

Gary Yamamato was the original inventor of the bait and built his entire company off of its success. But he never meant to design just a worm that fluttered on a fall. He actually was inspired by the slug-go worm, a popular soft jerkbait style worm at the time. He believed by using a better quality of soft plastic than competitors, he could create a more realistic moving slug-go that darted.

But he found when he made it with a slender design and the soft plastic that it was actually catching fish on the fall, not when he jerked it like a slug-go. So with a little tweaking we ended up with the senko – maybe the greatest bass catching bait of all time. 

So when the senko was invented – it wasn’t trying to mimic anything at all. It was really a fortunate accident that was just stumbled upon while trying to make a completely different bait!

what a senko imitates and why it works

A senko imitates a worm

If you go looking for a senko or any stickbait at your local tackle store, you’re going to find it in the section with all the other soft plastic worms. And for pretty good reason – it’s the type of soft plastic that it most resembles.

So naturally it’s very possible that a senko mimics a worm falling in the water and slowly sinking to the bottom of the lake. If you have every dropped a live nightcrawler into a pond you’ve likely seen this yourself. The worms will float momentarily and then slowly begin sinking, wiggling as they fall down.

This slow fall is maybe what a bass thinks a senko is in the water. A very very large earthworm or the like just falling to its depth and an easy meal to eat on it’s way down. 

The shape of a senko isn’t like most worms I have seen though. They are very large and thick, not like an earthworm which is much more slender. And how many worms just fall from the sky and in front of a bass’s mouth anyways? Sure they wash in or maybe get dropped by a bird. But they aren’t as common as say a crawdad or shad. But then maybe that is what makes them so irresistible… they’re unique!

A senko mimics a leech

what a senko imitates and why it works

A close cousin to the worm is the leech, which is another good option for what a senko is really mimicking to bass. Leech’s are parasites that live in freshwater, usually in shallower areas like swamps, and often attach themselves to living organisms to survive by feeding on blood.

So if you don’t believe a senko imitates a worm, you might believe instead that it mimics a leech. Leech’s are very often shorter than your typical worm and much fatter – particularly after a meal. If you look at a leech and a senko side by side, you can see a pretty good similarity.

But the issue is leech’s don’t just fall to the bottom of the water with a slow fluttering motion like many worms. They actually live in freshwater and can move in it easily, almost in a swimming motion. Could the senko wiggling as it falls seem like a leech swimming? Probably not.

So the size profile here does fit a little better. A senko probably looks most like a leech. But the movement? Leaves some room to be desired.

A senko resembles a dying or dead baitfish

What if a stickbait is supposed to look like dying bait fish? There are few things that get bass as exicted as a baitfish in distress. Flukes, crankbaits hitting the bottom, ned rigs, swimbaits, spinnerbaits, I can go on and on about the amount of baits that are meant to look like baitfish running away, swimming, or dying. We know that bass eat smaller fish as much as anything else. And a dying fish is an easy meal.

If you have ever seen a fish dying, you’ll know that they don’t just often die instantaneously. Often there is a period where they are swimming sideways, floating to the top, then kicking around back down into the water fighting for their life.

what a senko imitates and why it works

What if a senko is imitating that dying motion? Is a bass seeing it as a baitfish that is dying and floating around limply in the water and just jerking around every so often? 

This isn’t a theory that everyone agrees with, but I can see some validity to it. I mean I have caught plenty of bass in white and silver senkos that look just like shad or other minnows. And I have seen a dead fish floating with just a little movement that looks kind of like a senko. A baitfish on its side and stickbait kind of have the same profile as well.

The floating down part is hard for me to understand though since every dead fish I have seen floats to the surface, not the other way around. But whose to say bass are smart enough to know the difference between sinking and floating? 

A senko doesn't imitate anything - it's an invader!

We have covered the main three theories on what a senko is actually imitating, so lets go on to other theories of why bass bite them so well that doesn’t have anything to do with a stickbait looking like a food source bass often eat.

Bass are known to be predatory fish that will bite things as a reaction as much as because they are hungry. It isn’t just a meal, it’s almost as if they are asserting their dominance over smaller species or things that surprise them.

So when they see a large thing in the water just slowly falling down right by them, maybe they can’t help but bite it not because they’re hungry, but because they just don’t want it near them.

While other baits will go by a bass more quickly, a senko is maybe the only one that will sit right in a bass’s face for a few seconds. This is just enough time for the bass to get annoyed or anxious by its presence and therefore they bite it to get it away from them rather than actually eating it because it looks like food. Or it’s just a natural reaction to something that is so close to them.

This is an interesting thought that I think can’t be understated. Senkos are more unique than any other bait because they slowly fall instead of being worked or reeled. Almost no other lure is retrieved this way – which is maybe what makes them so powerful.

Also, this would explain why senkos work when nothing else does. You aren’t trying to encourage a bass to feed – you’re just annoying them with a potential invader in their space.

That said, I have seen bass travel a few feet to bite a senko as it falls as if they are attracted to it for some reason. Not just that it fell on their nose and they decided to eat it. So I’m not sure this answers why a stickbait works all the time. But I think it maybe is an overlooked aspect of it.

what a senko imitates and why it works


So now we get to why I believe a senko works so well and what it is imitating. And the answer is…. All of the above.

The beauty of a stickbait is that it actually mimics features of a lot of food sources bass eat. Worms, leeches, dying baitfish – it has aspects that remind bass of all of them which makes them so inclined to eat it. Then, on top of that, even when they aren’t hungry something falling so close to them turns on their aggressive mentality to bite it. Just to prove they are the predator and get it away from them.

I believe it’s this combination of all aspects that makes the senko a deadly bait for catching fish when nothing else will. If they want any type of food – it can imitate it. And even if they aren’t hungry it can just annoy them into biting. That is what makes it so special.

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