Ways to make a creature immune to bullets other than bulletproof skin? [duplicate]

In my story, I want a creature to be immune to bullets, but giving it bulletproof skin seems too obvious. I want it so that you could shoot the creature a few times at its seemingly vital spots (the head, heart, etc.), but it won't die right away and can still escape or attack you. The best way to make sure it dies quickly is by draining most of its blood, which means you have to get close enough to cause a large wound with a bladed weapon.

Yes, I know you can just use a really big gun or explosives to achieve the same effect, but in this scenario, the options are limited to something relatively cheap, lightweight, and doesn't cause a lot of collateral damage. To give you some image, the creature is about as agile, as strong, and as big as a polar bear.

Preferably the reason it's immune to bullets is based on real animals, or at least something that could exist in the natural world.

marked as duplicate by Tim B♦ science-based StackExchange.ready(function() { if (StackExchange.options.isMobile) return; $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() { var$hover = $(this).addClass('hover-bound'),$msg = $hover.siblings('.dupe-hammer-message');$hover.hover( function() { $hover.showInfoMessage('', { messageElement:$msg.clone().show(), transient: false, position: { my: 'bottom left', at: 'top center', offsetTop: -7 }, dismissable: false, relativeToBody: true }); }, function() { StackExchange.helpers.removeMessages(); } ); }); }); Jan 30 '18 at 11:31

• what sort of guns are shooting, what caliber bullets do you want to stop, there's a big difference – Kilisi Jan 30 '18 at 9:32
• The guns that people are required to take to the arctic are not your usual hunting rifles. A polar bear is dangerously close to bullet proof already. (Also the guns need to be very reliable in the cold). – Windlepon Jan 30 '18 at 9:34
• "which means you have to get close enough to cause a large wound with a bladed weapon." This is going to be your big problem. There are a number of ways to make animals mostly bulletproof, but they pretty much all make them blade-proof as well. I think you may be underestimating the amount of bleeding that gunshot wounds cause. Anything that can be killed with a sword or axe can pretty much without a doubt be killed by a mediocre rifle. Guns are just better at killing things than bladed weapons. That's sort of the whole point. – GrandOpener Jan 30 '18 at 9:46
• Remind me of the anime Blood, where vampire cannot be killed by bullet, you need to cause huge blood loss to kill them, hence sword fight in a modern setting. Their explanation boil down to "magic" however. – DrakaSAN Jan 30 '18 at 10:09
• @DonFusili Fair enough, but different guns and ammunition cause different size entry and exit wounds. Further, real hunters aim for penetration because piercing vital organs is a good way to kill stuff. In a world where making things bleed is how you kill stuff, the guns and the hunting tactics would be focused on that. I just don't see any realistic scenario where swords cause more damage than guns. – GrandOpener Jan 30 '18 at 10:49

The skull would protect the brain of course, and you could have a ribcage where the ribs are more tightly packed (or even overlapping dual layer, allowing expansion in both layers but still protecting against vital shots) so that lungs, heart et al are protected. You still need a circulatory system so the idea of large trauma from a blade still works.

Sure, you could get a shot into the arms or legs, but that would not be fatal. Even a stomach wound wouldn't kill the animal immediately meaning that it could still attack you.

It violates the possibility of the brain, heart or lungs being shot, but still provides for firearms to do damage generally, just not in critical areas that would cause immediate death.

This does have some precedent in nature; certain herd animals have hardened skulls, and there are plenty of dinosaurs with hardened skeletons as they used parts of their bodies as clubs, rams or spears.

• I like the idea of a double ribcage, but how would it evolve? – John Dvorak Jan 30 '18 at 7:11
• @John the same way our ribcage did, but on a planet with much higher risk of mechanical damage? – Mołot Jan 30 '18 at 7:26
• @JohnDvorak, Molot's right but that mechanical damage might have first taken the form of (say) a T-Rex jaw. If you have large predators in the past and dual layer ribcages protect lungs and heart from the teeth, the predator may not have the crush capability to kill its prey. If it relies on sharp teeth penetrating vital organs, this seems like a logical evolutionary defence. – Tim B II Jan 30 '18 at 7:59
• @TimB Well to be fair, to survive the jaw of a T-Rex your ribcage would have to be made of steel and be able to resist to 400,000 pounds per square inch of pressure. But you have a point – Hankrecords Jan 30 '18 at 9:53
• Actually I was quite interested in this T-Rex thing, so I asked it in a separate question – Hankrecords Jan 30 '18 at 10:17

Um why not use an actual polar bear? Or something very similar; bears, especially the big bears, (Polar and Grisly) are notoriously hard to kill with small calibre rounds, the combination of muscle layers, fat, and fur over their primary body cavity makes getting at their organs really unlikely with handgun rounds. They also have very thick muscles and bones in their skulls so headshots often lodge near the surface breaking bone but not punching through.

• Yeah, but you can still kill a polar bear with a large caliber rifle... – M Arif Rahman Winandar Jan 30 '18 at 10:06
• @MArifRahmanWinandar You certainly can but the OP did say the only available gun was a "light weight". – Ash Jan 30 '18 at 10:17
• I don't think "get close enough to cause a large wound with a bladed weapon" is a recommended technique for killing polar bears though. A skilled martial artist might manage it, but "shoot the bear through its eye socket" would work for a sufficiently skilled shooter (and accurate gun). – armb Jan 30 '18 at 11:27
• @armb Boarspear is the recommended weapon if you're dumb enough to want to take on a bear at that range. In theory it's long enough that the bear can't kill you while it's on one end and you're on the other. – Ash Jan 30 '18 at 12:08
• +1 because this makes the most sense without having to invent a new creature. And because polar bears are awesome. – Hankrecords Jan 30 '18 at 13:55

Amorphism, if the creature has no vital organs but rather is composed of "full function" non-specialised cells that all do a bit of everything but require a certain critical mass to function as a whole. Then point damage like a bullet wound does little to no damage to the overall organism while cutting it up with a sword reduces individual sections below survival mass killing chunks of it off until the whole no longer has enough cells to grow back. Something like the Oozes of Dungeons and Dragons or Calvin in Life. Real world examples of amorphic life are the Sponges that have mutable cell functions based on location rather than a fixed function for a given cell.

• Yeah, my first thought as well. If the creature is vaguely humanoid in external appearance, you don't even need to have a convoluted way of killing it - just disable them from doing harm. Running at you with claws? Cut the hands off. Teeth? Cut the head off. Even if it doesn't kill them, it will stop them. Then it's just garbage to throw in the furnace. The key is decentralization - instead of a "tree" of arteries and veins like we have, have a uniform network of capillaries; a bullet round can't cause much bleeding, and it can't cause hydro-static shock. Severing the limbs still works. – Luaan Jan 30 '18 at 11:37

Backup Organs

You can make it resistant to most attacks, including bullets, by having redundant vital organs. Combined with a fully shared cardiovascular system and enhanced coagulation, this seems to fit your prerequisites.

• Shooting it will hurt and damage it, but the backup organ will take over, allowing it to flee and fight another day.
• Enhanced coagulation makes sure normal wounds not targeted to drain the blood supply will not result in too much blood loss.
• A fully shared cardiovascular system allows major blood drains to be fatal.

Examples of this exist in nature where certain animals have multiple copies of the same organ. Taking one out vastly reduces their quality of life, but still allows them to survive (Octopi and their three hearts, most insects and their compound eyes etc.). Evolution is as such not a problem, your species would just take existing features and take them to the next level.

• Resist piercing: Projectile immunity is usually best achieved by avoiding getting pierced. Some ways to shed bullets include:
• hard surfaces
• angled surfaces
• low coefficients of friction
• active deflection (springy bristle like hairs could provide this, as would orienting body surfaces)
• Resist momentum: Projectiles impart momentum and that is the source of damage. Ways to resist imparted momentum are:
• having a much larger mass
• "low viscosity" or low yield strength (if we fail at a point then we can't spread the momentum to areas adjacent to the point as easily)
• mass shedding. Having a skin layer absorb momentum and shear off means we have ablative armor that carries momentum away .
• Die to bleeding:
• Blades would have trouble finding purchase on a surface smooth enough to help deflect bullets. But conversely that may make catching on the non-slick wound easier. Repetitive damage in a single area is generally not good.
• In a creature with low viscosity overall it would lose internal fluids quickly. To not die from a bullet it would need something like a self-healing skin, porous and highly elastic. So bullets could open a pinhole. But a blade would open a larger wound which would be fatal. Alternatively you could add something like platelets that congeal on contact with air. Larger wounds are just harder to congeal.
• Extremely hard materials could be brittle (typically a standard trade-off) so the higher impact from a blade or hammer could be enough to break it where a bullet would not. Death by bleeding then just being standard.
• Extremely large objects absorb the momentum outright and the bullets and blades can only go so deep. But Blades have the potential to hack away chunks of material and dig deeper. Something a bullet has a hard time doing.

Hardness and mass tend to hand-in-hand material wise. So you could go with a tank-like creature. Alternatively something akin to a slime with special skin would work as well. Mix and match if you need protected areas (skull for example). Other options exist as well.

Your creatures may have a reasonably thick layer of ballistic gel or blubber-like material under their skin, which scope shall be to slow down and thus absorb most of the kinetic energy of bullets, sparing damages to vital organs.

You can either change the density of the material (shortcoming: it makes the thing heavier) or its viscosity to improve the effectiveness of the dissipation.

• Ballistic gel is made to reassemble pig meat, so that's exactly what a hunting weapon is designed to pierce, isn't it? And it's heavy. Why would any creature evolve so much dead weight? – Mołot Jan 30 '18 at 8:26
• @Mołot, just trying to fit in OP's specs. In a world where lots of bullets fly, a dead weight might be better than a dead body. – L.Dutch Jan 30 '18 at 8:57
• Maybe change the "ballistic gel" to something like blubber (bullet absorbing blubber) as it seems the only special property of ballistic gel (it simulates tissue) isn't really important for this answer to work. In fact, looks like there were some advances in non-newtonian fluids which apply to bullet prooffing (e.g. this and this) - they'll probably won't block serrated blades though... – G0BLiN Jan 30 '18 at 9:13
• What if it was something like sand? – Hankrecords Jan 30 '18 at 9:55
• Isn't this just a variation of bulleproof skin? – M Arif Rahman Winandar Jan 30 '18 at 10:06

How big is this creature allowed to be?

I'd like to take this in a different direction than the other answers: make the creature "sparse" (as the crown of a tree) and/or large (as a coral reef), so that point-effect weapons (such as bullets) have a very low chance of doing significant damage.

Maybe combined with vital organs somehow being distributed or in unforeseeable places, and you really have to hack it to pieces in order to kill it.

I realize this makes it look more like a very lively plant than an animal, but depending on your reality ... that line can be surprisingly blurry anyway.

Redundancy.

Bigger than necessity organs due to evolutionary pressure to survive wounds and duplicated vascularisation with the possibility of closing many veins/arteries if severed.

Wherever you hit, there will be another part of the organ able to take over the function and the blood drain will be minor because the tissue can survive a long time without blood while healing and the arteries are closed or almost closed.

People can live with literally half their brain missing, make that per design and you can destroy half the head without problems.

Bonus: to kill it you need to severe both vital arteries at one of the few points where they are near each other.

FUR

What about a massive stubborn fur, that is thick enough to absorb most of a bullets energy or/and deflect it from it's original path.

HORNS

The creature also could have horn like growths around its vital spots, which can deflect a bullet from the vital area when incoming on certain angels.

This still mean that a bullet may be deflected to a less vital area or if shot at the right angel (which might be difficult) still might hit a vital area. This makes it also very challenging to hunt such a creature.

Self-Regenerative tissue

your creature has a very fast inmune and regenerative system, making beheading (or very big caliber shots on the head), and thus cutting all neural links, the only way to kill it.

disclaimer: your creature might have strong bonds to young-adult self destructive women, cigars, muscle cars and alcohol.

regeneration by chemical reaction is possible