This is a partial extension to this question: What kind of natural armor would stop bullets?

I was wondering if a creature could grow armor in such a way which would allow for it to detach a portion of the armor, and use it as a shield. It does not need to develop naturally, we have bio engineering on our side for this question. A couple requirements:

  1. It needs to be somewhat easy to get off the body.
  2. It should be able to be "reattached" to the body, and it would be nice if the armor could continue growing after being "reattached".
  3. It should not be for the entire body, the detachable bit would be located on the back of the creature.

UDATE: The reason detachable armor is developed is for inter-species fighting, where in some scenarios its helpful to have more forward facing armor, kind of like how knights used shields, even though they had armor. It would also work as "deployable" cover in times with guns, so those with lighter armor could still be protected from hostile fire.

Not every creature gets the detachable armor, just like not every human in medieval times got a massive shield.

  • 5
    $\begingroup$ This sounds like a worsening of the concept "a blanket too short to cover both head and feet". What's the point of uncovering a part of your body to protect it? Either you are adding no protection or, worse, you are exposing it. $\endgroup$ – L.Dutch - Reinstate Monica Oct 31 '17 at 6:29
  • 2
    $\begingroup$ @L.Dutch There are situations where sacrificing an armoured back plate for greater, and more mobile forward protection might be preferable. $\endgroup$ – Ash Oct 31 '17 at 9:10
  • 3
    $\begingroup$ I think people are thinking about this wrong. I don't think moving armor from back to front is that valuable. Moving armor from close to center of gravity where it is easy to carry and has minimal impact on mobility to where it can cover extensions such as the head might be of real value. Any impact on mobility is a constant "tax" on available energy and not losing your head is usually considered valuable in combat. $\endgroup$ – Ville Niemi Oct 31 '17 at 12:23
  • 2
    $\begingroup$ Does it have to be a detachable shield? How about a portion of its forearm (I assume it has to have one in order to use a shield), being designed similar to the frill of the frill-necked lizard, but armored. Article: en.wikipedia.org/wiki/Chlamydosaurus. Or an expandable armored "hood" similar to a cobra, but for the arm? $\endgroup$ – Rissiepit Oct 31 '17 at 13:42
  • 1
    $\begingroup$ Does it have to be purely natural? Would, for instance, an octopus holding a rock as a shield count? (The rock wouldn't grow, obviously, but the octopus could get a bigger rock.) $\endgroup$ – Ghotir Oct 31 '17 at 13:59

I'm going to suggest a parasitic symbiosis as the solution to this, the armoured "shield plate" on it's back is not in fact an integral part of the creature but is attached leech-like to its host. When circumstances warrant the host can send a chemical signal that loosens the shield's feeding tubes and allows it to be pulled off and used to shield the front of the host rather than its apparently less vulnerable back. When the danger is past the plate can be reattached to its feeding points and heal up/grow on until next time.

Do note that if this creature misjudges the situation it finds itself in then popping its back plate is probably going to get it killed in short order.

  • 1
    $\begingroup$ Good, logical suggestion! Though parasites and symbiotes are different sides of the same coin, as I understand it - the parasite eventually kills its host, while the symbiote and host reach a sort of you scratch-my-back (or shield it) kind of arrangement. $\endgroup$ – Rissiepit Oct 31 '17 at 15:27
  • $\begingroup$ @Rissiepit I'd always understood it to go something like parasites feed off the host there's another category that I can't remember where the host gets feed, and either can can apply to symbiosis since it describes a stable relationship. $\endgroup$ – Ash Oct 31 '17 at 16:16
  • $\begingroup$ +1 Two separate organisms is about the only way this will work. $\endgroup$ – John Nov 1 '17 at 4:00

Crustaceans do this routinely.

lobster with shed shell

from http://www.public-record.org/video/lobster-shedding-it-s-old-shell-for-a-new-one/TDLb5WcSREM

When crustaceans grow, they outgrow their shell (their "armor"). So they split it, crawl out and grow new. There is a period once they are out when they are soft - the carapace or shell must harden over some hours.

This is not exactly the same as the OP requests since the lobster cannot put it back on. But it is armor and it is detachable, and I can imagine something like a hermit crab carrying its old armor in front of it or on top of it like a shield. Some crustaceans (and also some sea urchins) put stuff on top of themselves for camouflage / armor - this hermit crab is carrying a fire urchin, which I think is about the most awesome shield a crab could have. Good looking too!


hermit crab carrying fire urchin

  • 6
    $\begingroup$ That crab looks like it’s about to throw that urchin in some sort of aquatic wrestling match. $\endgroup$ – Joe Bloggs Oct 31 '17 at 17:35
  • 3
    $\begingroup$ Crabs have also been known to wield sea anemones as weapons. $\endgroup$ – John Nov 1 '17 at 3:58

Yes but it's tricky to pull off

This shield needs to do a couple things to be worthwhile.

  1. Freedom of movement: It needs to be segmented to support movement while stowed on the back. Humans get away with strapping shields to our backs because the shield only attaches at two points. This shield will have continuous contact. If not segmented then the creature will need to be molded in such a way that this big plate doesn't impede movement.
  2. Rapid Reattachment: The shield needs to support reattachment on the speed of seconds. Anything longer will require regrowing things and that takes too much energy (plus added risk of infection. Gross!)
  3. Rapid Regeneration:Rapid hook-up to blood supply. This shield will need to regrow after being used. Blood supply means the shield can be a living thing. You'll probably want to design a crazy strong immune system to handle the inevitable infections. Also, this is totally unprecedented since there's no organism I know of that has what amounts to a external hydraulic valve for blood.

Segmented Shield, Detach!

A couple things need to happen to make the shield useful.

  1. Detach blood supply of shield from creature. Probably want to flush the blood from the shield back to the creature. This prevents blood loss when the shield is damaged and gives the creature a kind of battle-boost of blood.
  2. Detach shield holding mechanism. The mechanism could be a bunch of gecko foot pad like things that grip or intertwine with the shield to hold it in place.
  3. Make the shield rigid. There are a number of ways this can be done. It can be made rigid by attaching it to the forearm of the creature.
    1. Rigidity would then come from the bones in the forearm though this seems dangerous to me unless the forearms are also strengthened for the added load.
    2. Alternatively, have each plate interlock with it's neighbors. When there's blood flow to the shield, the space between the plates are pressurized, forcing them apart. This greater distance increases the range of motion. When there's no blood, the plates are elastically drawn back together, making the whole shield rigid. If the pressurized shield is hard to imagine, think of a spinal column. All the vertebrae interlock. Normally, they have a pretty small range of motion ~18 degrees. However, if you increase the space between each vertebrae, the range of motion is increased.
  4. Clean up the cilia that hold the shield in place when not in use.

This is cool, why tricky?

It's awkward because usually you want armor all over. Also, there's no precedent for this anywhere in real life. You want armor to stay attached for the life of the creature. If additional armor is required, it just grows in that location. There are a lot of bioengineering challenges that will need to be overcome to make this work. The creature would need to be designed specifically to its shield. Also, all the tissue in the shield will need to be able to thrive in an an anaerobic environment for hours or days when the blood supply is cut-off. This likely means that regrowth will stop during that period.

  • 1
    $\begingroup$ The battle-boost of blood sure seems interesting. $\endgroup$ – OneSurvivor Nov 1 '17 at 22:41

Yes, But It Might (Might) Not Be Bullet Proof

Here is a link to an article about a recently discovered gecko as of February 2017 (Could be earlier) http://www.cbc.ca/news/technology/new-species-gecko-tears-off-skin-1.3971889

It fits your criteria 2/3 times. This armor doesn't cover the whole body (I may be wrong though about this one), it detaches really quickly, and it regrows in a few weeks. Unfortunately they cant be reattached.

About the bullet proof thing, there may be a workaround. Chitons are mollusks that make their own teeth out of magnetite which is the hardest material made by a living organism. If you could have a combination of the Gecko and Chiton, there you have it, Regenerative, Detachable, Possibly Bullet Proof, Natural Armor


How about this.

Treat this shield more like the shell of a mollusk.

  • Abalone shells are incredibly strong and virtually bullet proof.

  • shells aren't directly part of their creature but a product of.

  • your creature could work on his shell for maintenance or growth whenever there is down time.

could attach and detach from the shell via a muscle


Perhaps something along the lines of a rattlesnake's rattle. This forms when the snake sheds its skin, and a bit remains behind on the tail and hardens to form another link in the rattle.

Granted, a rattlesnake's rattle isn't exactly armor (although the sound definitely serves as a warning), but a theoretical creature could shed a skin or shell that hardens like the rattle, and then carry that around. Bonus would be - it would get a new shield periodically, in case the old one was damaged or lost.


Many shell animals like oisters have a muscle that is attached to the uppershell. If instead it can grab hold of it and also let it go, you can have what you want.

The armor would grow on a piece of flesh/skin that creates the armor substance. This piece is connected by detacheable bloodvessels, and the small area between the pieces is covered in mucus and such against infections.

The creature can have it's muscles let go of the armor, the bloodvessles detach and the creature can take it off. If you have similar armor pieces at various places, you could replace a busted piece of armor with a new piece, allowing the busted piece to heal on a less vital/less likely to hit area. Or as mentioned you can carry the piece of armor as a shield. When re-attaching a piece of armor the bloodvessles also re-attach and whatever constricted it lets go. It's likely that the muscle(s) holding on to the armor will simultaneously support bloodvessles and nerve endings that connect to the armor. Its also smart to have dozens of small muscles hold on to the armor and to have the muscle basically lock a bony potrusion in place so that it doesnt have to expend energy holding it. Another advantage of this is slight movement capability of the platings to increase or decrease agility. Decreasing agility can help with adding more forces when pushing or lifting for example.

Many operations on arms and legs happen by first taking the blood out, these operations can take up to 7 hours before the bodypart starts degrading permanently, so a piece of armor would likely survive for as much time as well. 7 hours is more than enough time for a battle, or temporary re-attachment.


a limb that folds back onto the creature's back, and with its extension shaped like a shield, would work. For example many kinds of crabs have one of its pincers very large to plug up the hole it lives in. When the creature is at rest, this limb folds back and functions as additional back armor/for easy carrying, and when in use, unfolds and docks to the creature's forearm, giving the impression that it is taking off a shield from its back.

  • 2
    $\begingroup$ Folding back is not the same as detachable. $\endgroup$ – L.Dutch - Reinstate Monica Sep 19 '18 at 7:16
  • $\begingroup$ We don't seek to unilaterally discourage answers that need to tweak the requirements of the question just a little. But when a good answer does that it justifies why tweaking the requirements actually gives a better answer to the spirit of the question. In this case the spirit of the question seems to be mostly about it being detachable, yet your folding limb is not. Why? If there is a good reason that could be interesting. $\endgroup$ – Jared K Sep 19 '18 at 14:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.