Could genetically engineered horses make cavalry survivable on a battlefield with modern technology? While machineguns made cavalry obsolete, could there be a way that horses could be modified to be useful again? You would also get of one of the main issues of cavalry solved as you wouldn't have to worry about horse breeding making war horses rare. This cavalry can use both guns & any melee weapons. (Effectively the only thing that used to keep infantry from being destroyed by cavalry charges was formations but modern infantry doesn't take up formation so a cavalry charge would be effective against modern infantry if they didn't get annihilated on the way there.) This genetic engineering is limited by real world constraints. The tradeoffs between size & food consumption are still there. If an organ is included, it has to exist in a already existing animal. If another animal would be a better baseline for this, it can be used.

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    $\begingroup$ Could any downvoters answer WHY they downvoted so the OP can adjust his question accordingly? We should perhaps start introducing a forced comment for any downvoters to make sure the OP always has the chance to know what he could do to improve. $\endgroup$
    – Demigan
    Commented Jul 31, 2021 at 9:33
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    $\begingroup$ @Demigan: Downvoted for the unsustainable affirmation that modern infantry would be vulnerable to horse cavalry charges. Modern infantry battle tactics (as opposed to urban combat or anti-guerilla tactics) are designed to work against machine guns and cannon; any reasonably trained modern infantry battalion would laugh at an enemy trying to fight them with horse cavalry charges. The querent seems to have forgotten all the hard lessons so many people died in World War I to teach us of how modern infantry fights on a real battlefield. (The keyword is entrechment. Modern infantry digs.) $\endgroup$
    – AlexP
    Commented Jul 31, 2021 at 11:22
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    $\begingroup$ @AlexP but that is not what the OP is asking. Quite literally he says that cavalry charges were made obsolete due to machine guns and he asks for a way to make horses valuable on the battlefield again. He's not requiring that use to be cavalry charges, and mentions that cavalry charges would only be useful again if the horses could somehow make it passed that very machine gun fire you mention. $\endgroup$
    – Demigan
    Commented Jul 31, 2021 at 12:54
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    $\begingroup$ @AlexP My point isn't that modern infantry are vulnerable to cavalry charges, my point is that if cavalry could somehow get there the infantry would be destroyed. because without a formation there is no way for infantry to survive a cavalry charge if they somehow got there $\endgroup$
    – OT-64 SKOT
    Commented Jul 31, 2021 at 13:23
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    $\begingroup$ @jamesqf We need an artillery battery to create massed cannon fire. During WWI cavalry was still very successful when attacking infantry in a non-fortified position. After WWI, machine guns had become more mobile and ubiquitous (and rifles improved their firing rate too), so an average infantry platoon had become capable of repelling a cavalry attack. Development of tanks ("armored cavalry") had been the final nail in the good old cavalry's coffin. $\endgroup$
    – Alexander
    Commented Jul 31, 2021 at 18:08

7 Answers 7



Armoured cavalry is faster than horses, carries self-propelled guns, is more capable of traversing most terrain, and offers a much higher combat value-per-unit than any animal could.

You could make horses that ate half as much and spat acid, and they wouldn't come close to the utility of a tank brigade in modern warfare.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch
    Commented Aug 1, 2021 at 19:01
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    $\begingroup$ Sort of obvious, but perhaps answer could be better by adding that armored vehicles are going to be better armored that horses. $\endgroup$
    – Dast
    Commented Aug 2, 2021 at 15:13
  • $\begingroup$ What if the terrain is really steep? How much of a slope can a tank drive up? Horses are small and nimble (compared to tanks...) $\endgroup$ Commented Aug 2, 2021 at 15:32
  • $\begingroup$ @user253751 Experimentally, a tank can handle a 60 percent grade. There are probably specific rough terrain situations where a horse might be more manoeuvrable, but a hill is not a problem for a tank. Most equestrian magazines suggest not taking a horse up a trail with a grade steeper than about 20 percent because coming down they're prone to injury. $\endgroup$
    – jdunlop
    Commented Aug 3, 2021 at 6:23

Change the battlefield:

Frame challenge: To make horses practical on the battlefield, you need to change the nature of the modern battlefield. I think Nepene Nep covered good engineering for these horses. Short of giving intelligent hexapod horses functional arms to carry weapons in, you aren't going to change horses enough to make them practical on the field.

  • Man-portable super weapons: If every individual soldier has a relatively cheap, rugged weapon that can destroy any vehicle on the field, then planes, tanks, and possibly eventually even trucks and jeeps will become an expensive and wasteful investment. There will still be a need for transport, but weapons will make the form of transport as cheap as possible. Trenches would be ineffective except as a fixed and vulnerable means of concealment. My favorite weapon in this case would be some form of mini rocket launcher with various types of specialty munitions, but lasers, plasma guns, and the like are all fodder for these weapons.
  • EMP: If these weapons (or related weapons) unleash massive amounts of electromagnetic interference, then drones and robotic weapons will be rendered increasingly worthless. even vehicle ignition systems will be rendered obsolete, and trucks would need to move troops to the edge of the battlefield, then drop them there or risk being incapacitated. Even missiles today are extremely dependent on electronics, and would need long "dumb" portions of their attack to overcome abundant EMP attacks. Surveillance and communications on the battlefield would be operated by simpler and simpler systems as even radios were destroyed.

So to actually carry men faster on the battlefield, or move supplies about in and quantity, you would need horses (or something like them). Infantry on horses with hit-and-run tactics would be more mobile than infantry. Any equipment in the direct field of conflict would get hauled by a horse or a horse-drawn cart.

Horses are still used in primitive conditions (especially in asymmetrical warfare) for hauling and mobility, but can't compete for these functions with modern equipment. So get rid of the modern equipment and see what happens. What is old is new again.

  • $\begingroup$ I like the EMP battlefield concept. You don’t need electronics for effective vehicles but they all have them now. There would be a period while you retooled your vehicles to go without electronics and during that window horses would be useful again. That would make exciting fiction! $\endgroup$
    – Willk
    Commented Jul 31, 2021 at 14:23
  • $\begingroup$ No weapon is likely to keep such big advantage for long. Some counter-measures will be developed rather quickly. $\endgroup$
    – Jan Hudec
    Commented Aug 1, 2021 at 22:04
  • $\begingroup$ A diesel engine does not need a single electric wire. Sure, most have electronic control these days, but they can run just fine without at the cost of a bit of efficiency, and using a hand-crank for start. And we can probably shield electronics well enough that an EMP will start killing people before it kills the electronics anyway—don't forget the heart is basically an electronic device too. $\endgroup$
    – Jan Hudec
    Commented Aug 1, 2021 at 22:06
  • $\begingroup$ @JanHudec That's why I led with a weapon capable of destroying all vehicles. You need to be able to destroy lots of stuff with a man-portable weapon - the kind of firepower-over-armor advantage that transforms the battlefield. EMP is just to take all the other recon/communications/robotics out that could counter the advantages of a guy on a horses over just a guy. Obviously no system can predominate forever, but it could long enough for the OP's world to go back to horses. Oh! EMP-resistant horses! And soldiers with AED's relying on their semi-intelligent horses while they are unconscious... $\endgroup$
    – DWKraus
    Commented Aug 2, 2021 at 2:06

Yes, however not as cavalry but as Dragoon type brigades.

Armies of today live on money, fuel, manpower, mobility, fuel, spare parts, money, skillful training, maintenance, production capcacity and money.

Thats a lot of money, but also a lot of fuel. Especially an area like europe if it was ever cut off from fuel import would have little capacity to create its own.

Using genetically engineered horses to reduce fuel consumption while still creating mobility is a good idea. Rather than replacing existing vehicles, they would simply be additions to currently un-mechanized infantry. The infantry would use the horses to get around faster than they would without vehicles and retain their stamina for a fight, while also carrying more supplies. The horses can be genetically engineered to eat just about anything, from grass to leaves and bark to human waste. That way they can survive for longer without needing specific food supplies.

In combat the horses are used as Dragoons: you ride them out of visual range of the enemy, then dismount just before you go to fight and leave the horses behind. This means each soldier can bring more supplies for combat, they can reach their destination on the battlefield faster and they have more stamina for the actual fighting. The horses are genetically engineered to be smart enough to recognize uniforms and not need tending while left behind. That way horses could hide themselves from danger, look for food or react to the soldiers calling them back should they need them again.

Edit: since any organ from other animals is allowed, to make the horses more resiliant to shrapnel and bullets you could use spider silks. Spidersilk could be made within the skin of the horse, where the surrounding cells will pull it between them allowing the strands to migrate and reinforce the skin. Spidersilk farming takes a lot of time and effort which makes it rare, but with the addition of many spidersilk glands throughout the horse's body and the fact that it will likely be a few years old before it is used it has time to create a reasonably thick layer of added spidersilk protections.

Add in other skin types, badger and bear skin both is thick, loose and tough. Bears can hit each other hard with sharp claws without causing significant damage, and Grizzly bears are notorious for their resistance to small-arms. This would also help the horses survive getting hit, although the most important word is "survive", not "remain fully capable of continueing". This is in no way a free pass to survive sustained fire, even if the skin was 100% bullet proof the sheer concussive impact of a machine gun would quickly incapacitate and eventually kill the horse. You could improve their ability by making them Grizzly sized animals but that would also mean a larger, more food consuming animal that would unlikely have the niche you want.

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    $\begingroup$ Don't forget that on some terrain horses can be used while armoured vehicles can not. Or more easily. Some rocky or mountainous terrain, or soil that is incredibly soft. Weight limitations and movement limitations. Horses in the meantime are more difficult to track compared to tanks while being able to carry heavy infantry weapons and supplies. Not saying they are better than armoured vehicles, but there's a reason some nations still have trained soldiers on ski's. They can offer advantages. $\endgroup$
    – Trioxidane
    Commented Jul 31, 2021 at 7:35
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    $\begingroup$ Horses (and animals in general) are horrible engines, from an efficiency point of view; aside from special uses (where they can go where tracked or wheeled vehicles cannot) their only advantage is that they can burn grass, but then Europe is not exactly a vast underpopulated grassland. You'd be better served to use modern-ish steam engines instead of horses. There is a reason why even primitive steam engines displaces horses as motors. $\endgroup$
    – AlexP
    Commented Jul 31, 2021 at 11:11
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    $\begingroup$ @AlexP that is what the genetic engineering is supposed to solve. Also that is why you would not replace vehicles, but instead use them for people who would normally not receive motorized transport near the battlefield. $\endgroup$
    – Demigan
    Commented Jul 31, 2021 at 12:47
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    $\begingroup$ @AlexP : "even primitive steam engines displaces horses as motors" - not really, not in all cases. They displaced them as convenient mass transportation, but even as far as in WW2, there were more horses used in total than all engines combined. $\endgroup$
    – vsz
    Commented Aug 1, 2021 at 0:42
  • $\begingroup$ @vsz, the use of horses during WWII was due to production limitations. The United States, which had as much industrial capacity as everyone else combined, used almost nothing but trucks. $\endgroup$
    – Mark
    Commented Aug 1, 2021 at 1:45

Yes, because machine guns aren't the top counter to horses.

Infantry are worse at handling machine gun fire than horses because they're slower. Only very heavily armored trucks can handle machine gun fire.

The main reason why armored cavalry replaced horses is because they have greater strategic flexibility. Horses require lots of water and food and die of exhaustion and while you can go 30 miles on a horse in a day, you can go that far in a few hours on a decent road in a truck, and they just need a load of gas to keep going, or a few replacement parts.

Horses also require riders to spend several hours a day grooming and feeding and training horses every day.

When trucks became much more cheap, it just wasn't financially worth it keeping horses around.

As such, there's a single simple modification that could make horses more valuable today.

Make them much, much smarter, loyal, and fearless.

Horses who were intelligent and loyal could clean and feed themselves. They could forage for food and train to be better hoses. They would be like human soldiers, but better. This would reduce their cost a lot, and give them greater flexibility.

Them being fearless would make them much more willing to ride through gunfire and artillery shells.

Make them able to eat a wider range of food.

Some alterations to stomach fauna would broaden their ability to survive on whatever foods. This would allow them to feed in hostile environments where it might be hard to get petrol for vehicles.

In terms of their role, we have long since moved past the time of infantry charges. Now small squad warfare is the norm. You have small flexible squads of soldiers that can work together to use cover, ambushes, and covering fire to defeat enemies with less casualties.

Horses with their immense agility would help do that. They could ensure machine gun ammo was in the right place, or quickly move a sniper to a safer position. They could fire at people from a position humans could never reach in time.

The goal would be to use their superior speed and tactical flexibility to hurt enemies more. They'd be of most use in places with bad roads or urban environments where pure speed and distances were less of a concern and places where air superiority is not assured so you can't just scout with a plane.

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    $\begingroup$ Hmm. First, you're talking about breeding an intelligent/ sentient animal purely for war. Which is a major ethical issue. What if this new species rebels? Or when the war ends? Secondly, each new-born "centaur" is going to need to be raised/trained. Which will be costly and take years - at least humans are usually teenagers with a basic education by the time a gun is shoved in their hand. Then too, horses are big (vs humans) and slow (vs vehicles) and consume a lot of resources, even if you assume they can forage. Overall, it'd be better to genetically engineer the humans! $\endgroup$
    – Juice
    Commented Aug 1, 2021 at 0:50
  • $\begingroup$ Horses can rebel even if you don't Gm modify them, so, and with modification you can make them loyal. Op didn't ask for me to explain how to decommission the GM horses, or to be ethical. Horses are more agile than vehicles, especially in congested environments like cities. $\endgroup$
    – Nepene Nep
    Commented Aug 1, 2021 at 15:22
  • $\begingroup$ Not quiet, at the beginning of WW1 there where dedicated horse battalions, especially on french side, who where devastated and completely wrecked. I recall especially one situation where only 2 machine gun positions killed over 800 soldiers in less than 10 minutes. It's not about whether a horse backs down from mashine gun fire, but it is pretty unhandy to bring a 2 m target onto a battlefield. Mashine guns ARE the number 1 counter to horses! $\endgroup$
    – user59660
    Commented Aug 1, 2021 at 20:33
  • $\begingroup$ Machine guns devastated everyone in ww1, infantry and horses. They kept using infantry and horses, and had some successes with horses. $\endgroup$
    – Nepene Nep
    Commented Aug 1, 2021 at 21:42

No, not cavalry

Modern combat tactics are mostly about stealth because offensive power has (generally) outstripped defensive power. This is visible in modern infantry doctrine, which revolves around small squads moving from cover to cover to gain a tactical advantage before engaging or providing intelligence that let them direct more powerful weapons like CAS or a mortar attack. Basically, there are very, very, few situations in modern military combat where you can see the enemy and you can't almost instantly kill them or be killed by them.

This means that cavalry wasn't phased out because horses are vulnerable to machine gun fire, it means cavalry was phased out because the strategy is incompatible with modern military doctrine. A cavalry force is a large mass of soldiers who ride against an enemy in battle, but who are they going to engage? It's not like there will be a couple hundred or thousand enemy soldiers conveniently lined up in a field somewhere for the cavalry to run down. No, they'll all be in small squads, spread out and hidden, and ready to blast the highly-visible cavalry group away.

That said, the modern military still uses horses, particularly in special operations environments where mobility over extremely tough terrain is required and large loads need to be transported stealthily. A genetically engineered horse could fill that role, and there's a reason that the military invested millions of dollars into robotic pack-animals that combine the best of both worlds: easy handling and care along with all-terrain legs without the detrimental psyche and animal needs of a horse and the inflexibility of wheeled vehicles:



Limited by real world constraints? No.

Horses are big targets that aren't good at moving quickly other than in straight lines, and getting shot one time is enough to seriously reduce their effectiveness. Now, consider that these days, every infantryman carries around an automatic weapon, and consider the fact that there is no genetic modification that lets a horse survive getting shot multiple times.

They work better for special forces rather than cavalry.

Now, if we had supertech on hand, this might be possible, but the resultant creature wouldn't really look or act like a horse anymore.

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    $\begingroup$ Surely horses move in L shapes not straight lines! (Sorry, I couldn't resist.) $\endgroup$
    – IMSoP
    Commented Jul 31, 2021 at 21:59
  • $\begingroup$ LOLl Indeed, that's the only modern battlefield they are still effective on. $\endgroup$
    – Jasen
    Commented Aug 1, 2021 at 3:31

To expand a bit on @DWKraus's answer (better individual weapons): Turns out metal is incredibly easy to detect, and large masses of metal (say, anything larger than cell phone) aren't really viable on the battlefied any more. Man-portable smart missiles made primarily of plastics have removed essentially all vehicles from the battlefield (and probably all squad weapons to. Maybe you don't even want to carry a pistol any more...); the missiles have enough smarts that you just aim them in the vague direction of anything and it's going to get hit and destroyed. Valiant efforts by tank units to do point defense with their own missiles were unsuccessful because the plastic missiles are great at killing metal objects, but not great at killing each other.

You're going to want transport still. Wooden wagons, horses, etc. The horses probably still won't get used as cavalry (as in fighting from horseback), but fighting as dragoons (dismount to fight) is extremely common.

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    $\begingroup$ Metal's easy to detect, but giant warm animals aren't? This seems like it'd have to involve a lot more than just genetic modification. $\endgroup$
    – jdunlop
    Commented Aug 1, 2021 at 2:45
  • $\begingroup$ @jdunlop You're not wrong, but it seems like the handwaving you need to say that "sensors can easily detect metal" + "really good man-portable ATGMs" + "we can confuse heat sensors more easily than metal sensors" seems like it's perhaps a bit more acceptable than pure-fantasy genetic engineering - but this is probably just a matter of taste. You're 100% right that neither one of them are actually realistic. $\endgroup$ Commented Aug 1, 2021 at 22:44

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