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Life had been good for a certain class of tetrapods. They evolved two layers graphene in a specialized collagen creating a relatively thin yet seemingly impenetrable hide. All of their natural predators moved on to other prey without such tough skin, but soon over competition for plants struck. Many of them remained herbivores, but in order for many members of this class to survive, carnivory had to evolve again. It would be difficult, but probably not impossible, as no creature could truly make perfect graphene. Perhaps small flaws in the collagen itself could be exploited.

The collagen not only contains graphene, but also copper to support its structure. Both copper and carbon are a major and plentiful part of the diet for these tetrapods.

I am mainly concerned about the required materials to damage the graphene. Would they be biologically attainable and maintainable? I omit to go in depth about the structure of the collagen so that liberties can be taken. After all, if the graphene collagen were too difficult to damage, the tetrapods would have faced mass extinction due to overpopulation. As a basis, currently, the creatures are constructed with the same elements animal life on Earth is, but in different concentrations. There is more copper than there is on Earth, but many animals use hemoglobin in their blood, plus iron in their bones.

I am always interested in hearing about new elements to incorporate in their biology, so if anything else would be helpful, it would be great to know. So far, I have pictured mostly teeth and/or claws, as those weapons seem to work very well for predators on Earth. In the end it comes down to whatever can get the job done (as long as the predator still has a good chance of being alive afterwards.)

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  • $\begingroup$ It depends on the Graphene what results might be viable. I always read that Graphene is about 5 to 300 times stronger than steel (but what type of steel is still a mystery to me). Pure Graphene is elastic so it would only keep sharp things out, it wouldn't stop a hammer from crushing whatever armor is below. Graphene with deliberate defects will become harder but also lose some of it's strength, so it might be pierced. The best way I can think of beating these type of creatures is by trying to send shockwaves through the armor into the body to rip bloodvessels, lungs and organs apart. $\endgroup$ – Demigan May 26 '18 at 7:56
  • $\begingroup$ Also it sounds a lot like these creatures created Diamene: graphene-info.com/… $\endgroup$ – Demigan May 26 '18 at 8:01
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    $\begingroup$ graphene is inflexible so either these creatures have large exploitable gaps or they are so stiff you can drop them in a shallow pit and let them starve to death. $\endgroup$ – John May 26 '18 at 14:19
  • $\begingroup$ @Demigan They did. That was why I mentioned two layers. $\endgroup$ – Roki May 26 '18 at 14:42
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Attack what inside and what is exposed.

No matter how you skin your creature it's going to suffer just as much from impact damage (think e.g. broken bones) and things like suffocation or crushing.

In addition shock waves from impacts will still travel through the body and cause damage. In this regard consider the effect of a nearby shell burst to a human which does not cause any exterior sign of injury. It can still rupture internal organs as a result of the shock wave and kill in moments.

An animal can blind you either temporarily or permanently. Deafen you.

Simply immobilize you. Eventually you starve to death.

Drag you to e.g. water and drown you.

I can heat you. Even if your skin is intact, the heat will cause damage internally and most creatures can be killed by heat (or lack of it) pretty quickly.

Poison. Always a good choice.

I am mainly concerned about the required materials to damage the graphene. Would they be biologically attainable and maintainable?

I'm not at all clear how your creature can biologically create graphene. It's not a process I can see being produced in nature.

My (limited) understanding is that graphene is brittle, especially when impure and is also prone to edge fracture (and somewhere there will be an edge).

By comparison methods of imparting high impact, crushing, suffocation and so on are innumerable. Nothing special required.

iron in their bones

This achieves what I wonder ? My knowledge of alloys is limited, but I can't think of a particular advantage of mixing iron and calcium.

I think you might need to read up on the complex structure that is typical animal bone.

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Eat the whole thing.

If you have an impenetrable shell, that will not help if you are eaten in your entirety. Eventually your shell will open, or your digested substance will come out through your eye holes. This is the method gray whales use on clams.

gray whale feeding on bottom sediment

https://www.arkive.org/gray-whale/eschrichtius-robustus/video-08a.html

This species is the only cetacean to feed by straining the sediment on the sea floor. Individuals roll onto their sides after diving to the bottom and take large amounts of sediment into their mouth. As the whale rises to the surface it strains the contents of the mouth through the baleen, leaving a trail of mud and sand behind it. The invertebrate prey consisting of bottom-dwelling crustaceans, worms and molluscs is isolated in this way and swallowed.

So too your creature. Its predator eats it in its entirety. Maybe the predator is much larger, as a whale is larger than a clam. Or maybe the predator has an expansile stomach like a gulper eel or anaconda. In any case - in it goes and then time and enzymes do the rest.

The untouched graphene skin might be retrieved from the feces of this predator.

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When people talk about Graphene being strong, they often forget that there are many different types of strengths. The strength of macroscopic materials also are highly dependent on the lack or presence of defects. Graphene with defects only has about 4% the strength of pristine graphene.

Typically small samples of graphene are tested. The weakness of graphene will be in small defects. Well it turns out graphene is actually kinda brittle.

There is a good chance that the skin of your tetrapods at the joints, and other flexible points will have many cracks. Predators would eventually learn to go for those joints.

However, if you don't like that, you could just have the graphene skin be impenetrable. It does not mean that they would go extinct from over population. Many species do not have natural predators and other environmental pressures can keep their population in check (such as limited food supply).

However, there is another route you can take. Graphene can react chemically (though for the most part it requires defect sites to do so).

If a predator could oxide some of the graphene skin (such as if it had evolved a way to produce a mixture of sulfuric acid H2SO4, sodium nitrate NaNO3, and potassium permanganate KMnO, or something similar), it could spray it on the skin. Once graphene become oxized, it is easily permeable by water (and I am assuming blood), and your tetrapod would bleed out through its skin.

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Tasers

Graphene is an excellent conductor of electricity. Getting hit with a taser would be devastating because the impact would not be localized between the impact points as it is in humans and would instead spread across the whole body and in extreme cases, cook the organism inside.

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    $\begingroup$ Actually the other way around. Graphene is an excellent conductor of electricity so you'll experience absolutely nothing. Normally a taser will send electricity into your skin, where it will then mess with your nervous system which is better at conducting electricity and the electricity will try to find a way to the earth. With a Graphene skin, the electricity will just move through the least resistence IE the skin and into the ground. Lower resistance also means less heat production so less chance of scorching whatever is against the Graphene. $\endgroup$ – Demigan May 26 '18 at 8:00
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Option 1

Graphene is essentially pure carbon, several carbon atoms arranged in an hexagonal pattern on a plane.

Carbon is well known for its eagerness to oxidation, and the lack of any other atomic species around make it just easier for the chemical reaction to start.

So my guess would be that any attack based on oxidative species (oxygen, halogen gases, etc.) would have good chances of being successful at damaging the graphene skin.

Option 2

Another possible direction is the usually played games of evolution: when a defense gets better, the offense improves, too.

Graphene, like diamond or rubber, can be good against 1 particular attack, but can be vulnerable to others. It's just a matter of exploiting it. Take porcupines, for example. They might look tough to attack, yet some predators have learned that flipping them on their back gives access to a juicy lunch.

For the case in discussion, if graphene can be developed by living organisms, nothing forbids that also predators can produce and use it in their jaws/claws.

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  • $\begingroup$ So given that a substance that oxidizes causes damage, if claws and teeth were covered in a mucus or saliva containing say, hydrogen peroxide, could the skin be weakened enough? $\endgroup$ – Roki May 26 '18 at 3:33
  • $\begingroup$ @Roki I think a better question would be "could the skin be weakened fast enough". If it takes half an hour before you can finish off your target it's kind of a weak way to attack it, especially if you have to find the exact same area to bite again. But I'm also interested in how well Graphene oxidizes. $\endgroup$ – Demigan May 26 '18 at 8:04

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