Figure 1

Guest Blogger: Michael Vorhis, author of ARCHANGEL suspense thriller, OPEN DISTANCE adventure thriller & more to come

This blog post is more of an invitation for any and all readers to share theories than it is an attempt to treat a topic with some kind of professed thoroughness…because that would be impossible. It’s about a subject near and dear to all our hearts. It’s about jumping trout.

The question is…why do they do it? Yes, yes, the usual–to catch stuff, but I mean…in plain sight of anglers? I know a place I’ve been trying to decode for years, without success–a place where sizable trout leap completely out of the water with regularity, generally all day. I can see nothing in the air they’re going after, and they don’t seem to hit any dainty tidbits I offer, such as nice little mayfly patterns or Griffith’s Gnats or #20 gossamer drys or the Elk Hair Caddis. I’ve assumed they must be going after tiny midges or gnats invisible from where I stand a mere 20 feet away, although the light and clarity are always so good that I could see even a very small bug if it was there…and nothing ever is.

And it makes little sense to me that a beautiful, wild 15-inch rainbow would expend the energy to power itself fully out of the water, tail and all, in pursuit of prey whose biomass can’t possibly offer enough BTUs to make a hundredth of that effort worthwhile. Makes no survival sense at all.

Figure 1
Figure 1

I suppose one could speculate that trout, like the great cats, respond to fleeing prey without stopping to do the math; I concede that that can be the nature of hunters. But to expose themselves to the eyes of otters, hawks and men, all for a taste of something that couldn’t be any bigger than the point of a pin…basically I still don’t think Nature is that dumb. To jump for a bug, I think it would have to be a worthwhile bug to take the risk. Good fish will barely poke their noses out from their undercut banks for small insects. So launching bodily out of the water is a quantum leap from that cagey behavior.

Or I suppose one could speculate that some kind of insect so small a man cannot see them from a few feet away in rays of sunlight against dark green backgrounds might tastes so good that otherwise crafty predators throw caution to the wind in broad daylight. I find that about as believable as a man on the WWI French front leaping up out of his trench in pursuit of a getaway jellybean.

These fish also swirl on the surface, but again I can detect nothing emerging. The water here is glassy smooth, and eight or ten feet deep; it moves at a crawl–about two or three mph–very serenely toward a riffle 50 yards or more downstream.

I’ve heard the theories that jumping fish may be divesting themselves of parasites. But I find these musings somehow difficult to credit, for a number of reasons including the fact that air is no more abrasive than water and that the fish I’ve caught in this river are not exactly festooned with barnacles. If I move very slowly toward where my cast can reach the point of the last few leaps, I’ll see a leap upstream of me instead, just out of a cast’s reach. And if I try to cast there, another leap happens a little downstream. They know I’m there, but they leap anyway.

Aggravation doesn’t begin to describe it…and it happens in this particular place all winter and all summer. These are nice rainbows–wild rainbows.

If they’re going after something, it’s got to be either in the water or above it. Nabbing a tiny fish on the surface wouldn’t launch them bodily out of the water with their mouth at the apex of the jump. Nabbing an emerger wouldn’t either. The emerger theory does come to mind when the fish swirl, but there are no adult insects coming off the surface that I’ve ever been able to detect, and I can see no larvae rising toward the top from below.

Have you ever wrestled with the “what the heck are they leaping for” question? Then you must have tales to tell. Theories. Stories. Ways to prove them out. I think we’d all love to hear observations, and especially tales of having solved such a puzzle.

Figure 2
Figure 2

So fire away! Let’s hear those theories, experiences and suggestions. Don’t neglect the angle that leaping takes energy and that Nature should be smart enough to know what a mouthful of bug is worth. Well that’s a given in my mind anyway…but maybe not.

Honestly, the only theory I’ve ever heard that almost made sense was: “Trout jump in full view of fishermen because they don’t have middle fingers.” That one I can just about believe.


  1. I’m going to add a comment myself, as a starter: I went back out there today, and it’s still as I described. I think the full-breach leaping and the aggressive swirling, while they do occur with equal regularity in the same areas, have to be separated into two different categories of behavior.

    My best guess is that the leaping is indeed done to catch tiny little nothings–adult midges, which are usually present in the air in at least some minimal numbers when the leaping is occurring. Since an adult midge can’t possibly yield enough food value to make such a leap worthwhile, I suspect the motivation is “sport” or “practice” or maybe the tiny things just taste great. Mammals play and leap and chase things too, regardless of size, and while it’s true that mammal craniums are worlds more complex than those of fish, it’s also true that such practice and play and instinctive chase instincts serve most species well, in general, in the survival game. No need for the Supreme Being to wire a predator to chase but then apply complicated caveats like minimal size of prey…just wire them to chase, and be done with it…and it’ll all even out.

    That’s my best guess, for the leaping.

    The swirling is a very different matter…and more interesting. It’s definitely a predatorial attack–I see sizable fish “pouncing” on something that’s on or near the surface, either with a turn-and-slash or by coming down on the prey from above with a fast and targeted surface-breaking roll. I think this prey cannot be an emerger–the attacks are just too swift, too aggressive, too ambush-like. Emergers are not nearly agile enough to warrant such attacks–they can be sucked in from below. Unless fish are racing each other to each emerger (and I think I’d see evidence of competing fish if that were true), it’s just not necessary to mount a surprise attack on an emerger that hasn’t broken the surface yet.

    So I think the swirling and pouncing have to be attacks on something that is good at evading. My best guess is little baitfish–probably “minnows” (in the non-species-specific sense) that are themselves converging to go after the adult midges, which do represent a meaningful mouthful to them. And the swirling and pouncing is invariably seen near-ish the bank or some other structure, where one might expect little baitfish to hang out, looking for little bugs, so that tends to support my theory too.

    So: It’s the swirling and pouncing I should be targeting, not the wild leaping after bugs smaller than any #22 fly I own. If I’m right about the prey, then I’ll need a little streamer that resembles whatever “minnow” species are in this river.

    Well, that’s my latest theory. Still, I welcome stories that could help…even if they challenge my best guesses to date. I do very much want to decode this problem; these fish are very good fish for this stretch of river–I saw some today that I’d have given my spare reel to hook into. And whatever they’re preying on is bringing them to the surface in broad daylight. Hard to see that as anything other than a real opportunity.

    Stories and theories please! Lots of ’em! We all struggle with this kind of thing and we’d all welcome such experiential data.

    – Mike

    1. Mike,

      Asking why, when it comes to behaviors of trout or any other fish or animal is fraught with anthropomorphism. Although scientists do a good job of describing behaviors, they are generally left with merely theoretical explanations of why. Rarely is there any “scientific method” of experimentation that proves or disproves those theories. In a Jungian sort of why, trout jump because they can. Why remains a mystery. I’ve heard all the different explanations you mention–shedding parasites, because its fun, attacking prey, etc. None of which can be proven scientifically. I’ve even read that steelhead and salmon jump to loosen eggs from their skeins before spawning. The fact that Salmonids do jump, occasionally, is reassurance for the angler to their presence. Nothing is more frustrating on water you know holds a lot of fish than no rises, no follows or even no sightings. When that little guy leaves the water in your peripheral vision you are reassured that something is about to happen.


  2. Very true Mike, and I do take it as encouragement to see that good fish are present, healthy, & currently active. The task then turns from explaining them to enticing them, and any success has to be seen as support for (if not proof of) theories that give rise to it. If I adopt theories that lead toward better success, I’m happy to forego proof.

    Right now I’m going to focus more on the slashing and swirling more than the jumping. It’s clearly indicative of some serious feeding and tends to explain why multiple buggy offerings are being ignored by those particular fish. I’ll add more small streamers to my tactics on this river, up against the banks where I see slack water and midges in the air.

    Then we’ll just dang well see who has a middle finger and who doesn’t…. 🙂

    Thanks for your thoughts Mike,

    – Mike

  3. I have seen thirty inch open-mouth browns leap out if the water like tarpon on a particular lake fairly often. They are searching underneath feeding fry. Of course, this doesn’t explain eight to twelve inch trout leaping with wild abandon on the same lake. And it doesn’t explain similar leaps on streams.

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