Let us say you are some young Lakota Sioux brave on the High Plains with your spear, and you have the misfortune of seeing an American bison headed straight for you at top speed while you are in a box canyon of sorts. Having heard apocryphal tales of how white-man was able to withstand horse-charges by planting the butt of his spear in the ground and angling it upward to cause the horse to impale itself during the charge, and not having many other options due to your unfortunate location, you decide to try setting your spear against the charge.

Do you wind up going home a hero, or being found dead on the plains three days later, gored/run over by said bison?

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    $\begingroup$ I might point out the tales he heard about Infantry standing up against Cavalry also involved very long pikes, so even if there was impact, it was anywhere from 8 to 12 feet away from you, not in your face. $\endgroup$
    – Thucydides
    Sep 1, 2016 at 2:59
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    $\begingroup$ I think the solution is to re-ask this question, but replace our Lakota Sioux brave with a Scottsman, and the spear with a caber from the caber toss. For additional fun, assuming the Scottsman is piss drunk. For even more fun, assume the Scottsman got the bison drunk first! $\endgroup$
    – Cort Ammon
    Sep 1, 2016 at 3:44
  • $\begingroup$ If you want to have this dude return home a hero, have him fling the spear at the bison so that it stabs it in the eye, piercing all the way to the brain. This would require that the spear length be ~5 feet and it has a particularly sharp spike. The distance where the spear hits the bison should be nearly 30 feet from the Sioux hero. $\endgroup$ Sep 1, 2016 at 8:04
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    $\begingroup$ How is it related to worldbuilding? $\endgroup$
    – enkryptor
    Sep 1, 2016 at 10:03
  • $\begingroup$ @CortAmmon Are taking the piss out of a serious situation. The caber is excellent idea though. $\endgroup$
    – a4android
    Sep 1, 2016 at 10:25

4 Answers 4


He chose... poorly.

With a tough and dense enough haft, and a really solid set against a mass comparable to the animal in question, and most importantly, one of these:

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with a crosspiece to stop the animal in question from driving themselves right up the length of the spear and into you, you might accomplish that thing with minor injuries only.

Not with a light, short plains native spear though, which would probably bend and/or break on impact. Sorry, buddy.

  • $\begingroup$ The crosspiece is really the weak-point -- it would have to be strong enough not break off and big enough not to just bury itself in the bison. It's hard to see what material available to a Stone Age tribe would serve. And if it does, now the shaft has to be strong enough (and well anchored enough) to deflect three-quarters of a ton of angry pot-roast charging at 50kph almost 45° off course. I think the expression "Happy Hunting Ground" will take on a very sudden significance to our stalwart young Sioux. $\endgroup$ Oct 21, 2016 at 21:08
  • $\begingroup$ @Malvolio Lakota Sioux, white man, stone age tribe? I think you grossly misestimate either the time period this question clearly deals with, or the people it deals with. $\endgroup$
    – user
    Jan 23, 2017 at 19:19
  • $\begingroup$ @MichaelKjörling: I don't understand your comment. There was no native civilisation in the Americas which progressed beyond the Stone Age. They simply stayed in the Stone Age long after other people in other places moved on. $\endgroup$
    – AlexP
    Jan 23, 2017 at 22:09
  • $\begingroup$ @MichaelKjörling -- the Stone Age ends for a group when it learns to smelt metal. In Asia, Europe, and South America, that happened 10,000 years ago; in North America, Australia, and sub-Saharan Africa, only within the last few hundred years. There are many theories put forward for this discrepancy, but one that I find both convincing and relevant is that societies with access to large, domesticable animals (llamas, horses, water-buffalo, yaks, camels, and cows, but NOT bison, which are murderously intractable) could advance to the point of developing metallurgy, but if not, not. $\endgroup$ Jan 23, 2017 at 23:11
  • $\begingroup$ @AlexP -- I disagree. The Incans smelted gold, silver, copper, and bronze, which would qualify them as a Bronze Age people. Like the medieval Chinese, they never managed to leverage their advantages (metal-working, functioning civil society, llamas, wheels) to become a true technological society, I don't know why. Maybe the rough terrain of their geographical homeland made commerce too difficult. $\endgroup$ Jan 23, 2017 at 23:17

When spears were used against cavalry charges it was en mass. Multiple ranks of soldiers would stand shoulder to shoulder presenting a wall of spears to the enemy. This is what would dissuade horses from charging into the formation.

In the case of a lone Lakota Sioux standing against a charging buffalo, its inertia will be enough to carry it into you, probably crushing you in the process. If your aim is true you may be able to fatally wound it. Which is a weak consolation prize when you've been hit by the equivalent to a hatchback crashing into you at 30 mph.

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    $\begingroup$ So what you're saying is I need the spear plus a really good roll using my shoulder to get up and over the windscreen of the bison? This is going to be so awesome on YouTube. $\endgroup$ Sep 1, 2016 at 9:44

The american bison has a charge speed in the range of around 35 mph, weighing in at roughly 1400 - 2000 pounds. All of this calculates to over 13,000 Newtons of force.

A Lakota Sioux warrior's spear is only 57 inches, or about 4.75 feet.

Now adding that the Newtonian force required to break a human femur bone is around 4000 newtons, the most likely occurrence in this situation would be that whether or net the spear impaled the bison it would quickly snap or be torn from the young man's arms, and the bison would continue to quickly run him over.

So this would probably not be our friends most promising course of action. Sorry!


Now I was asked about my calculations. To calculate the amount of force in any situation, we use the equation; Force = Mass multiplied by acceleration.

For the mass variable in our equation we can estimate the american bison at 2000 pounds (probably the worst case scenario). we can convert that weight to just over 907 kg. The bison in question will have a speed of 35 mph, so where do we get our acceleration? In this instance we are concerned about the acceleration of the young man's spear, as well as himself. The young man is not moving relative to the earth but he will be quickly accelerated when the bison collides with his braced body. Thus our acceleration (the speed at which the bison will collide with the man and attempt to move him), at 35 mph is 15.6 m/s.

Edit 2: Sadly I'm a bit rusty when it comes to calculating force, but thanks to some comments I was advised on what needed to change.

So heres our calculation of acceleration: 15.6-0 divided by 0.05(the time in seconds, about halfway between an estimate given me) multiplied by 15.6 m/s^2

So this equation will actually give us a larger amount of force, because now our estimated acceleration is 20 m/s^2


So here's our equation now: Force = 907 kg * 20 --> Force = 18,140 Newtons

If our bison weighs in at a lower 1,400 pounds? Force = 725.7 kg * 20 --> Force = 14,514 Newtons

So when this best case scenario vs. worst case scenario are averaged out together it comes to about 16,300 Newtons! So after some recalculation and estimates, it seems the likely hood of surviving is even less likely, sorry again!

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    $\begingroup$ "The american bison has a charge speed in the range of around 35 mph, weighing in at roughly 1400 - 2000 pounds. All of this calculates to over 13,000 Newtons of force". Say what?! How did you make that calculation? Force is mass times acceleration, not mass times speed. $\endgroup$
    – MichaelK
    Sep 1, 2016 at 8:18
  • $\begingroup$ Well in this case it is DeltaV of a still standing person 0 and 35 mph. So the acceleration and the speed would be the same $\endgroup$ Sep 1, 2016 at 11:06
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    $\begingroup$ @Pakk isn't that what we try to achieve? $\endgroup$ Sep 1, 2016 at 11:13
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    $\begingroup$ @Pakk If the bison's deceleration would be half that, he'd take two seconds. Two times half the deceleration is still the full deceleration. If you exert half the force for twice the duration it's still the same amount of force. f=mass*(meter/second/second). We don't care how long it takes, so it becomes f=mass*(meter/second) $\endgroup$ Sep 1, 2016 at 12:48
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    $\begingroup$ @Micoxion: Less, definitely less; something around 0.01 to 0.1 s would be my estimate. And please give the equation for acceleration that you're using. Your calculations are misleading at first glance. $\endgroup$
    – nzaman
    Sep 1, 2016 at 17:13

The shaft would snap; the tip would pierce the skin, then slide off muscle; the bison would get angry(-ier); and the idiot standing 2 feet away from an angry, charging bison would get trampled.

If he's extremely lucky, the bison would think this was a good enough job instead of doubling back.

Smarter money is on running to the canyon walls and staying there. If it comes after him, the bison will risk running into the wall and injuring itself.

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    $\begingroup$ Or using the spear as a pole for pole-jumping over the charging bison :-) $\endgroup$
    – Falco
    Sep 1, 2016 at 11:35

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