Why Would Naturally Evolved Monsters Have Weak Points?

Question

This is akin to Why do my monster minions all have obvious weak points that instantly kill them?, but with one important difference: these monsters developed more or less naturally, they're animals that came into their present forms over years of Chaos Energy-induced mutation and natural selection.

Furthermore, small, relatively weak monsters (like Plops and Goblins) don't have weak points, it's only the big ones like, y'know, your typical dragon.

To make this even weirder, some powerful monsters don't have weak spots; things like boss-level ghosts and evil wizards. Most of these monsters are humanoids; in fact, chances are if a monster is related to or once was a member of humanity, they won't exhibit weak points. The few other monsters that don't exhibit weak points are things like Plopup, which lack a physiological weak point on their body but do have a single critical weakness (Plopup don't do fire, they don't regenerate when burned).

So, in essence, my question is: Why Do Naturally Developed, Powerful Monsters Have Obvious Weak Points? and only concerns those monsters that have these weak points.

In order for monsters to even have weak points, they should probably have some sort of advantage, or not affect one's chances of survival. The monsters who don't have weak points either lack a physiological weak point or don't, for whatever reason, ever develop obvious indicators of such weak points.

Basically, if magic is a natural energy cells can harness, why would it lead to magic-heavy creatures having glowing markings to indicate where their bodies are vulnerable? In other words, I'm asking why those monsters that have weak points would have them, when taking natural selection into account, as weak points would seem to impair one's chances of survival.

Going off this, please note that natural selection will likely affect weak points; they could end up in hard-to-reach points of the body, have some sort of protection that must be destroyed, removed, or worked around, or else be a relatively large vulnerable area instead of one crippling weak point. Also, monsters will be preyed on both by other monsters and adventurers, and this should be taken into consideration when answering the question.

Answer 1

The Square-Cube Law essentially states that if something, be it a chair or a person or whatever, were made twice as tall, twice as wide, and twice as deep, its volume and mass would increase by a factor of eight, but its ability to support that mass, its cross sectional area, would only increase by a factor of four.

https://kottke.org/15/10/scaling-laws-and-the-speed-of-animals

A creature as large as an adult dragon simply cannot exist without falling victim to the square-cube law and collapsing under it's own bulk. Unless, that is, it has a means of reinforcing its body using magic, which allows the laws of physics to be sidestepped.

The "weak point" is a specialised organ common in large monsters that taps the ambient magical field and passively provides a variety of magical effects required to support a large monster. Reinforcement of the bones and organs, an effect that allows the skin to remain tough but flexible (and a low-level passive healing ability to prevent pressure sores), perhaps a limited form of anti-gravity to relieve some of the mass... leading scientists and thaumaturges are uncertain about the exact mechanism, but adventurers know that if you can damage it enough the field will give out and the creature will have its lungs and organs crushed by its own bulk. This also explains the rarity of boss monster pelts, bones, etc. - most of it is damaged beyond use when the creature dies, and it is... challenging to skin and debone a live (and somewhat irate) dragon.

For your other creatures which are more reasonable in size, you might just say that some creatures are naturally so affected by chaos energies that they need a dedicated organ similar to the above that provides a significant natural healing or anti-magic effect just to "break even" (no or very mild passive healing so you can still hurt them, most of the organ's effort is simply put into not dying) and not be torn asunder by their own natural magic. Maybe this chaos energy builds up in the body over time, so older, more dangerous monsters have larger weak points to compensate.

I can think of a few reasons why the the "weak point" organ cannot be embedded inside the body - it needs to interface externally to absorb magical energy, or maybe it would work fine inside the body but the effects would not apply to the skin - the creature would be able to survive but immobile, or maybe it simply generates a lot of waste heat, and if it was entirely contained within the body it would cause burns (or some sort of nasty magical damage).

Answer 2

Evolution is not about the survival of one individual - but rather the survival of its genes

The common thread that applies not just to 'monsters' but to all life is that the genetic structure of an organism, not its individual strength, is what establishes progression.

This is why we have sacrificial plants that expend all their energy into a final 'flower', only to then be destroyed. Why? Because the act of pollination is more important than survival. Why do bees live sexless lives and die when they deliver only one sting? Because their sacrifice continues their genetic line in the form of their Queen.

It is posited even, that limits of our life span are intentional - ie. even our lifespan is limited to promote our genes, for what use to a genome is an organism that lives forever and does not allow the genome to continue to improve?

So it is easily conceivable for your monsters to have 'weak points':

• it may have been past reproductive age and can be (and should be) sacrificed.
• it may not have a reproductive role, like a bee drone, and thus concentrate all efforts on offence (such as a bee sting) and tasks, but not on survivability
• it uses the weakness to procreate (much like your example of a one that has no resistance to fire, much like some plants that use the fire as a collective signal to germinate)
• signal theory - ie. the monster 'looks' like a monster with an obvious flaw, or feature, that its mate sees as desirable due to signal theory

In the end, a 'monster' is simply another life form, and succumbs to the same pressures, evolutionary quirks and signal theories that all life must contend with.

Answer 3

Runaway sexual selection

The point of a peacock's tail is that it is extravagant and wasteful. "Hey, look at me, girls! I can carry around this stupid thing, and not get eaten."

Likewise, the weak points are obvious to other monsters of its kind. This makes them more sexually attractive, because they can survive despite them.

Evolution being what it is, random factors prevented them from arising in all creatures. Some of these are particularly powerful for the lack. Others may have had a beginning, but those got picked off because they were weak.

Answer 4

Because natural evolution is a balance between results and efforts.

On one side you cannot have a creature which has a contermeasure to any possible threat, because those are potentially infinite, and as a natural creature you have to deal with finite resources. At a certain point the benefit of adding protections is uneconomical. Think of an animal which can be resistant to some crushing impacts: it can resist a wolf bite, a crocodile bite and going up, but it would still be crushable by something, and if it wants to become uncrushable it would have to deal with threat like a meteor impact and so on, becoming unfit for living.

Additionally, some weaknesses are a consequence of the particular evolutionary path taken by the creature: land organisms took the path of breathing in the atmosphere, resulting in the "weakness" that they drown if submerged in water for long enough times, while water breathing creatures suffocate if left outside of water for long times.

Answer 5

Specialization

Evolution, in many cases, develops very specialized traits that make them highly adapted to the environment they live in. Both predictor and prey do this, in a sort of biological arms race. These creatures' body plans expend a lot of energy and time refining traits that improve their success in the environment. However, this does tend to allow other traits to atrophy. Example, a creature develops protective traits, building a massive shell and thick skin. This creature's speed and agility will suffer greatly, but it's protected. A prey animal would want speed and agility, so it has a thin skin and sleek body plan, not adapt to taking a blow.

This plopup you talk about focused on its traits to attack and consume its prey, using a body chemistry that is highly vulnerable to fire. Its genetics chose a body plan that worked well in its environment, not in a rare situation like being set a blaze.

Humanoid creature do tend to be fairly generalized. Not very strong or fast or have fantastical claws and spikes, but they also do not have these highly specialized traits that hinder their other traits.

Now, many of these highly specialized creatures do tend to be the first to go extinct when changing environmental pressures are encountered. They are highly adapted to survive in the here and now. When exposed to situations that do not normally exist in their environment, they will probably not adapt very well.

Answer 6

Magic is like a disease.

Magic isn't natural to anyone, and anyone not very smart will have it grow in a single, glowing spot to power their abilities. Wizards and smarter monsters can learn to hide it, but the magic doesn't want to be hidden, so generally it isn't.

This glowing spot, when dislodged with swords or guns or claws, will then be available to infest another organism which is stronger. This is as the evolution of magic optimized.

Answer 7

The Weak Point is a "Magic Lung"

I am assuming you are referring to weak points equal or similar to the "Obvious weak points" of the original question, i.e.: instant-killing, colorful, bright, light-emitting.

All those monsters either evolve from a common ancestor or have achieved the same organ via convergent evolution. This organ is really useful in a magic-rich environment: is an organ that allows them to absorb magic from its surroundings. This magic absorption is now inherent to how the body feeds and obtains energy, and allows this monsters to be so powerful like, for example, being physics-defyingly big.

The deeper it is into the creature's insides, the more inefficient it is, because the creature's own body blocks the magic from reaching the organ. As a consequence, most of them are located in or near the body's surface.

As a side effect of the magic absorption, part of the magic is "lost" and is irradiated as energy (magic and not), which is, unfortunately, visible for most of the creatures, including humans.

Losing this organ is fatal, just as losing the lungs is, as the creature could not "breathe" magic without it. Some mechanisms the creatures have developed to fight this vulnerability are:

• Developing multiple organs, so losing one can be (crippling but) survivable.
• Placing it in hardly accesible regions of the body, such as belly, under the tail, armpits... etc.
• Placing it under a hard skin, sacrificing efficiency for resistance.
• Placing it inside some sort of mouth (or the mouth itself), so it can be protected by closing it. This mouth still has to open to "breathe".

Answer 8

If the monsters aren't intrinsically magical, then they're only 'monstrous' based on their biology. And biology only has a limited tool kit to work with.

To put it another way, if your monster's are biological creatures then they're simply 'monstrous' in the sense that nature has taken normal physiological characteristics possessed by other animals and evolved them to extreme lengths.

So a creature becomes 'monstrous' when it becomes far larger, faster, more poisonous, more heavily armored, perhaps smarter etc and therefore far more DANGEROUS than all the other run of the mill creatures in its environment. Your monsters are the T-Rexs, great white sharks, stone fish, Triceratops, giant camouflaged spider etc of their local environments. All equipped by nature with a particular set of traits that make them deadly.

Two key points to remember though. The first point is that evolution is about compromise. Your 'monsters' can be giant fast predators, but they cant also be heavily armored and horned, they can be highly venomous and well camouflaged but won't be able to speed through the water like a mako shark. To excel at one set of traits, other traits have to be given up.

Its the same thing with humans BTW (apart from our brains). Humans are generalists, we can swim, run, and climb etc but we aren't particular 'good' at any of them compared to other animals of the same size. Same thing for our senses, we've got good color vision and hearing but our sense of small is way less developed than other species).

The second point? The term 'Monster' is one of perspective. It's a term humans apportion to creatures not necessarily something implicit to their nature. If they're not magical in any way then all you monsters are just potentially highly dangerous animals. The apex predators of their niche.

Answer 9

Three reasons working together:

The weakpoints haven't impacted survival

There are plenty of animals in nature with obvious weaknesses that would perhaps even be easy to exploit. But if the species still exists, it must mean that these weaknesses are not critical: even if one, two or twenty specimens end up crippled or dead because of the weakness, the situation is such that the species is able to go on: the damage happens sporadically enough that enough members are able to carry on the genes to the next generation.

Perhaps the weakpoints they have are not exploited by the fauna of their environment: evolution wouldn't "notice" something that doesn't threaten survival systematically. If the weakpoints are exploited, it doesn't happen on a large enough scale to matter.

Evolution is always ongoing

Evolution is not ever a settled matter: species evolve continuously, and over very long periods of time. Perhaps what makes the weaknesses weaknesses is a relatively new danger, introduced to the environment too little time ago to have any impact on evolution yet. Perhaps the weakpoints will be gone eventually, or perhaps they will not matter enough to be ever gone. Relying on evolution is not a good short-term survival strategy: perhaps the species will be wiped out far before the weakness could be eliminated by evolution.

Large creatures have significantly more cells, many orders of magnitude more than small ones. This makes natural evolution slower, especially if they are hard to kill: the less advantageous genes are not disadvantageous enough to allow or trigger a cull, and so they carry on.

Exposure to magic could accelerate mutation: that accelerates evolution, but, similarly to radiation, it's random and has no will of its own: no interest in creating mutations that are "good" or "useful": some could be weaknesses. Large creatures are more resistant to averse random mutation because their larger number of cells makes sure the probability of something bad being developed are much lower, but this is also true for positive things.

The weakness balances the species' population

Being able to reproduce without any hindrance is not an unconditionally good thing for a species: when too many individuals cohexist at the same time in the same place, resources become scarce, and this can lead to extinction if the lifespan of the creatures is long enough that there would be no time for the environment to recover by the time the surplus starves.

This is especially true for apex predators and very large creatures, since their survival depends on, respectively (but not exclusively), a healthy population of prey and very large amounts of resources.

A critical weakness that menaces in the environment can only exploit occasionally would help reduce population in the short-term, helping the environment resist the foraging by the large creatures enough that all can survive.

Disclaimer: I just like the topic, I'm not a biologist and I reported facts and expectations as I remember them and as they make sense to me, but my assumptions could very well be wrong.

Answer 10

The monsters are very good at fighting other animals once they get relatively close, but especially the very big ones are very heavy and need to spend a lot of energy to move around. On the other hand, they also need to eat a lot, but chasing the pray would be too expensive. Therefore they try to get their prey to come to them.

Originally the only individuals which were approached by other predators were individuals which had some apparent exploitable weakness and therefore these could prey on the predators without having to go on extensive hunts, giving them a evolutionary advantage. In contrast, the disadvantage of being vulnerable wasn't significant since everything coming close enough to exploit the weakness barely had a chance to fight the monster anyway.

Of course, since these points are basically used as a lure, it makes sense to make them as visible as possible, e.g. via magical lights.

Answer 11

If I may add something. I would say that a flaw/weakness may be present because it was at the beginning of the evolution, and in the current environment, nothing made it evolve.

See : we squishy male humans have a weak spot in our groin : hitting it will make us defenseless.

But our environment did not prompt us to evolve a protection for that.

I hope I make sense.

Answer 12

All your monsters have both weak spots and more defended places.

Humans hunting them have only taken note of those that proved beneficial to hit. For the smaller ones you can just hit them wherever. Humans are strong enough that what armour they have is trivial to pierce. For the massive ones. Their weak spots are armoured enough that humans have difficulty abusing them. Leaving only the in-between open to actually have enough armour in some parts to resist most of the damage a human can do. Whist still having weak points that are useful to exploit.

Plate armour that humans make has obvious weak spots near the joints. Natural evolved armour will have a similar construction. Creating weak points at places that need to move. Then for those monsters that have no obvious weak spot. then you may be looking at it in the wrong way. For those monsters everything is a weak spot. Just failing to notice any difference between parts of a body does not mean a lack of weak spots.

Answer 13

Extreme Biology

The biology of your world includes a variety of more.. esoteric capabilities that aren't generally common to ours and these typically require large external nodes which are both vulnerable to damage and signs of the creature's powerful nature in one go.

Imagine a creature with Flame-breath like a dragon, it needs a fuel-tank, because its glands can't generate enough fuel at a high enough rate to actually be useful. So it has a sort of expanded Craw in its throat like some birds that serves as containment for volatile incendiary chemicals. (The caustic nature of the fuel represents a problem similar in some respects to stomach-acid, with similar solutions)

Such a fuel-tank is obviously a major hazard if ruptured, so it has some armour plates to protect it, and generally hunches around it to keep the swipes of rival creature's claws from tearing it open. It may also use the fuel-tank rather like the expansive inflatable throat of a bullfrog, lighting it up with phosphorescence, or colouring it with vibrant skin-pigments as a mating display.

For another creature, they may well have huge engorged glands on their body that serve to pump regenerative substances into their blood in and after combat. Allowing a creature the size of a bus to re-grow lost limbs, heal mortal injuries and generally be more indestructible. Such glands are naturally rather vulnerable and will be protected vigorously, but cannot be kept inside the body because of temperature-control reasons, similar to human testicles.

They may even need to be destroyed in order to kill the creature without massive extreme overkill. As a side-note, such glandular secretions may have amazing medical properties if harvested..

Answer 14

Many real-world creatures have obvious "weak points" that aren't much of a hazard to them in practice because they are well-defended otherwise, one way or another. Humans sometimes represent an unusual threat to such creatures because we devise means of intensively exploiting these "weak points" that other animals might not engage in. It could well be in this setting that the monsters evolved glowing weak points long ago, but are too threatening/large/armored/etc. for them to matter, except when it comes to skilled human adventurers or what have you.

As an example, consider the right whale. Right whales are nearly extinct in the Northern Hemisphere, mainly due to intensive hunting. This is because right whales move slowly, tend to stay near the surface of the water, and float when killed due to their high blubber content. This makes them accessible and attractive prey for their only two known predators, humans and orcas. However, they can be over 60 feet long and can weigh 100 tons, making them difficult for any animal alive to hunt without using a sophisticated social strategy; as a result, there wasn't much pressure on them for most of their history to develop more robust defenses against predation beyond their size.

In your setting, it could be that all the non-humanoid monsters have a common ancestor that first developed the ability to use magic. Perhaps this was facilitated by a special glowing magic organ which was located near the skin/exoskeleton, making it visible from the outside. It could be that over time this species became reliant on magic to stay alive, and thus could easily be killed in theory if this organ was badly injured, but had other adaptations that made it very hard to prey on. If this species was very successful and this happened a long time ago, you could well have a situation where there is now a whole family of species all with an organ like this that are not much subject to predation on the whole on account of their natural defenses.

It could be that the humans in your setting have only recently developed the ability to hunt these monsters; some sort of new technology that allows their magic organ to be targeted has emerged, and monster-hunting types have seized upon it. Suddenly monster hunting is a new, dangerous, glamorous sort of profession that many daring people have decided to take up. Perhaps the potent stores of magical chaos energy concentrated in these monsters can be harvested from their carcasses and used as a resource to power things or increase the potency of human-cast spells—that would definitely generate intense interest in exploiting them if it could be done. A whole industry would develop before long.

If you wanted to dramatize this in the plot, you could have the organs become more robust or deeply internal (and thus less visible) or whatnot over time due to selective pressure exerted by large-scale monster hunting, if the monsters breed rapidly. This might lead to an "arms race" akin to the dynamics around pesticides or antibiotics, with hunters trying to develop novel strategies and new technologies being developed to target their magic organs despite their new adaptations. If they don't breed rapidly, then humans might quickly deplete their populations once hunting them has become commonplace, which might precipitate a crisis if the magic energy harvested from them is being widely used. You could even have both happening at once for different species, if the monsters are sufficiently diverse.

Answer 15

Constraints

You can't grow thick armour everywhere.

Real animals have vulnerable throats even when they might have thick armor plating on their backs.

Evolution only selects for resistance to threats your ancestors encountered

Real organisms that grew in the darkness of deepwater vents may be entirely incapable of coping with changes in pressure and light may burn their skin.

We, as humans, cannot detect when we're in a nitrogen atmosphere because our lungs detect high CO2, not low oxygen. We just fall over and die without panic. Because pure-nitrogen atmospheres are rare in nature.

If a creatures ancestors always lived somewhere hot they may have no system for surviving cold shocks.

Magic

When it comes to magical creatures, organs that allow powerful creatures to absorb Mana, by their nature, may need to be free from armor if they're to allow the creature to absorb mana. Maybe the nature of that organ and the mana it absorbs makes the thin skin glow.

Cover the magic-absorbing organ with thick skin or armour and it "suffocates" for lack of magic.

And it may need serious blood supplies to that organ such that wounds to that area are extra-deadly.

Smaller creatures or those not physically dependant on fast mana regen may not need such an organ. Much like how insects don't need lungs where larger creatures like humans do in order to get enough oxygen.

But a big powerful elemental beast? it might be able to shield it's mana-lung for a time but eventually it will need to "breath" mana, particularly after it's tired itself out from magical attacks, which means exposing it to the air.

Answer 16

I'm be no means biologist but kinda like evolution and have couple of free flowing ideas that you might incorporate, nothing very concrete but I hope it might be inspirational.

It really depends how you define weak point, if you go on more holistic route like your Plopup and fire. When you really think about every animal has that kind of weak point such reliance on oxygen content, pressure, temperature (especially cold blooded), exhaustion, starvation (small animal can literally die when they stop eating for few hours especially herbivores), sunlight/darkness, lack or too much reliance on single sense think (echolocation into middle of rock concert).

Although I admit that most of these weakness are either relatively slow and agonizing or unavoidable, instant. Neither is as fun for a plot as say critical spot or vulnerability to silver or something.

Apart from sexual selection that can lead to detrimental features, like infamous peacock tail. There is another rule that you might use ie. honest signals are expensive and they must be expensive, otherwise they could easily be copied by fraudulent individuals, making whole signal useless.

I can't think of any super concrete example but some critical spots that might be indicator that particular individual is highly resistant to disease, some kind of magic, harsh conditions or otherwise has some desirable trait.

There might also be another system in play albeit slightly far-fetched, their ancestors evolved some trait that used to be desired but now is detrimental and it's extremely difficult to evolve out of it usually applies to extremely basic traits like (4 limbs of tetrapod, or bilateral symmetry) or they some monsters had no time to do so.

Small animals usually reproduce faster so those pesky goblins could already evolve to at least cover traces of the weak point while ogres are on their way. Similarly small animals might be more pressured to cover it to survive while apex predators don't have that much of a pressure to do so so their rate is even slower.