I'm considering a situation where, in a certain environment, there are two specially adapted (to the environment) animals, a predator and its prey.

I'd like, for the purposes of a story, for both these species to develop intelligence. This would be to look at how this relationship between predator and prey changes as they evolve intelligence/sentience.

But, on earth at least, intelligent prey species don't seem to occur. But surely intelligence would be a benifit in evading predators? maybe just not the local maxima.

So I'm asking, how much pressure can this prey-predator relationship have on evolving intelligence? I envisage one getting more intelligent, more able to capture or evade the other, and the other having to evolve to compensate.

  • $\begingroup$ what do you consider intelligent? How clever/smart/resourceful need these animals to be to satify your criteria of intelligence? (keeping in mind that you claim that intelligent prey species don't seem to occur). $\endgroup$
    – Theraot
    Commented Feb 21, 2017 at 14:29
  • $\begingroup$ Although many prey animals aren't hugely smart, there doesn't seem to be an actual evolutionary bar to herbivores developing high levels of intelligence. Gorillas and elephants are all herbivores with high levels of intelligence. $\endgroup$ Commented Feb 21, 2017 at 14:31
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    $\begingroup$ Worth pointing out that we are intelligent prey animals. $\endgroup$
    – Joe Bloggs
    Commented Feb 21, 2017 at 14:38
  • $\begingroup$ I'd say a level where there is at least some language, and tool use. A rudimentary society, sentience as I've said. $\endgroup$
    – user28207
    Commented Feb 21, 2017 at 14:41
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    $\begingroup$ @princeprince Evolution of something as complex as intelligence is a process that takes millions of years. A common misconception is that evolution happens during the lifetime of an individual; that if the individual is subjected to pressure then a beneficial change will manifest itself. No, that is not how it works: either you are born with the advantage, or you are not. The pressure affects change over thousands of generations, nor during the lifetime of one generation. $\endgroup$
    – MichaelK
    Commented Feb 21, 2017 at 15:35

7 Answers 7


There is a reason why intelligence is not usually something that arises from selection pressures purely via predator-prey relationship. For a predator, it is usually more "cost-effective" to get immediate results by evolving larger claws, specialized teeth, bigger muscles, better digestion, camouflage, better vision, whatever physical enhancement they can get without sacrificing basic health and reproductivity. Similarly for prey, it's easier to evolve traits that will ensure they can pass their genes on better - faster run, body armour, horns, spikes, more camouflage, poison, herding behaviour. We have been having this kind of arms race since life evolved on earth and needed energy from somewhere for sustenance.

Intelligence is expensive. You need extra energy to sustain an organ/synaptic system/processing network (aka brain); you need that extra energy evenly all around the year, not just seasonally; you need to be able to sustain this added body weight of the above without compromising your survival ability; you may take much longer to develop and mature. Think about us - human females have dangerous and painful labour just to be able to deliver large-headed babies who need long gestation periods to develop; babies need a long period of education and protection before they are able to survive by themselves; we as people are interdependent on each other and our social constructs for even our basic daily needs; none of us can (without help, protection and tools) fight and survive against lions, tigers, wolves or even a pack of feral dogs. Our intelligence has come with a great 'expense' and the push towards intelligence needs to justify that expense. There has to be something so valuable that is gained that getting intelligence is worth more than getting physical adjustments.

Possible extra selection pressure for intelligence could come from:

  1. Climate change and environmental stress. Look at human evolution - we are champion generalists, able to adapt to any environment. Being adaptable means being able to make changes on the fly, asap, comapared to the thousands and millions of years it takes to evolve traits and changes by which time the situation may be wildly different. Evidence points we evolved this ability during a time of severe environmental change. Are your predators-prey living on a highly changing environment where they need to make quick decisions with limited basis in past behaviour/experience?

  2. Manual dexterity and ability to explore and make tools. Consider the octopus. Very limited interaction, if any, with parents, neural network distributed all over the body including limbs, mostly solitary, predator as well as prey, short-lived, nothing like the typical example of intelligent mammal we usually use to demonstrate intelligence. Still very intelligent and known to use tools. Any creature would need specialized appendages to explore and manipulate its surroundings. Having a sensory network to process, manipulate and make sense of the world around seems to be enough of a jumpstart to making ideas to change the "world" to suit better. Are your creatures living in a tactile world that can stimulate their curiosity and have appendages that can manipulate it to suit themselves?

  3. Continued access to nutritious food. Getting energy sources that can sustain a power-hungry brain and then getting the brain to think up new ways to getting that nutritious food, especially if it's not easily obtained (eg. bone marrow from scavenged prey, tools, fire). Omnivores and generalists have a advantage here. Sure, predators get a lot of nutrition but if their prey base is limited, they will only specialize towards better ways of catching that.

  4. Complex social structure and some form of 'language' or shared code of information storage. To survive tough times. Our vocal chords and linguistic ability may have started us on an upward spiral where getting smarter was the direct result of... getting smarter.

I can understand that these examples are a bit earth-bound but the basic question is still the same: sure, intelligence is cool but expensive to maintain; there needs to be something special to get it started.

  • $\begingroup$ I think it's an interesting point you make about us being generalists. I had considered that they would become highly adapted to a specific environment, at which point the pressure from the predator/prey link would push them further up an evolutionary chain, as it were. Think I'll experiment with changes in the environment, how the organisms might cope. do you consider being generalists as an important step towards intelligence? $\endgroup$
    – user28207
    Commented Feb 23, 2017 at 11:03
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    $\begingroup$ @princeprince The main benefit to intelligence is adaptability. Being able to benefit from a large amount of possible food sources means there is more of a reason to learn which foods are good and which are bad, and the best way of getting each kind. If a species eats only a few kinds of food, learning new things is a waste of time and energy - evolution will just "hard-code" everything it needs to know about its selected prey into its instinct instead. $\endgroup$ Commented Feb 23, 2017 at 12:59

Most prey species don't develop intelligence because grass doesn't need to be outwitted. All they require is the speed to escape or the strength to survive, and the ability to out-think a meadow. Then again, most predator species don't develop intelligence either, all they need to do is either outrun or out-think something that has a greater IQ than a meadow.

It's not a particularly inspiring situation is it?

The arms race is speed and horns and claws, not tools and intelligence.

Where do we see intelligence?

Apes, birds, ocean mammals, elephants, bees.

In here there is a predator-prey relationship between 'intelligent' species: Killer whales and whales. Both are predators near the top of the food chain, there's not much that can eat a whale other than an orca. Unfortunately neither are tool using so they're not what you're looking for.

Another consideration is of course the human. An intelligent mid-chain species, prey to big cats, predator to anything too slow to get away. We turned our intelligence and tool use to our advantage to eliminate the bulk of our predators. However neither prey nor predators developed a matching level of intelligence.

Where could an intelligence arms race lead?

The most likely answer to this is "out of each others food chain", the predator-prey relationship would rapidly break down. The clearest example of this comes back to humans and big cats, intelligence has mostly taken us off their menu. Why risk hunting something that fights back when you can eat something that doesn't? Lions don't much hunt elephants when there are softer targets around, but bears will eat each other when they're hungry enough.

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    $\begingroup$ Corrected a small grammar mistake and noticed 'orca' was marked as not a word, but one of the suggested fixes was 'orcs'. I'm officially confused. $\endgroup$
    – Frostfyre
    Commented Feb 21, 2017 at 14:56
  • $\begingroup$ Yeah, as I feared. I'm wishing to constrain it though to try and mitigate some of these things happening. Possibly by having a hostile environment. One in which both animals are highly specialised, and there is scarcity of food for herbivores, $\endgroup$
    – user28207
    Commented Feb 21, 2017 at 15:00
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    $\begingroup$ @Frostfyre, orcas are obviously orcs in disguise, at some point they'll rise up and eat us all. $\endgroup$
    – Separatrix
    Commented Feb 21, 2017 at 15:46
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    $\begingroup$ So the OP might be better off having them evolve separately (say on different continents) at first then meet each other at the fire and stone tool stage. $\endgroup$
    – John
    Commented Feb 21, 2017 at 16:51
  • $\begingroup$ @John, that would probably leave them in conflict over resources but not technically preying on each other. Though ritual eating of the defeated after combat may take place. One would eventually displace the other in the same way as homo-sapiens displaced the neanderthals. $\endgroup$
    – Separatrix
    Commented Feb 22, 2017 at 9:15

I want to share the same sentiment as Separatrix. Most prey have their "Intelligence" hidden in their ability to survive... usually traits developed through evolution.... Look at lizards for example... their tails can be removed and regrown so that if an attacker grabs them by the tail and removes it, they can still run off. Or you also have the reptiles that blend into their surroundings.

As stated in another answer, someone of the prey category in the current animal world doesn't really think too much as more of it is instinct. They don't walk up to a pile of grass and go hmmm, this looks tastey but if I eat this, I am down wind and my scent will be carried to the pack of wolves over there.

In your story, you can definitely make it so the prey-predator relationship develops into a chess match with the prey being your "defensive" oriented mind and the Predator being the "offensive" oriented mind like in sports. First you would need each side to develop the ability to critically think. Once that happens, you can pretty much take their mental growth anywhere.

As it was also commented though, this game of chess could very well lead to the fact that a predator would just give up and move on to an easier prey instead of constantly forcing the issue. This is a common trait in predators of all forms. Rapists, murders, thieves, narcissists, and so on and so forth. They target the easy person. A girl walking down the street wearing a skirt all by herself at 1 am with her head buried in the phone and not situationally aware of what is going on around her is MORE likely (please note the more likely and not this definitely will) to fall victim than a woman who is walking down the street, in a skirt, with her head up, all by herself at 1 am. The key difference is that with her head up and aware she is able to pay attention to anything sneaking up on her and be a better deterrent. Unless an attacker is dead set on this particular person (which it does happen), an attacker will more likely wait for an easier target than one that will fight and struggle.

Same can be said about burglary. If you got a dog, chances are, your house won't be broken into because a dog will bark their heads off giving more attention than what a burglar wants. Screen doors are an added layer of security to a house that someone would have to break through just to get to the normal door and can also be a deterrent. The key here is doing things that are a deterrent. That doesn't mean 100% of the time you are safe, but it helps increase the chances.

I could keep going on and on but I think you understand the point I am trying to make... the smarter the potential victim, the less likely they become a victim at all and will eventually be ignored all together as not worth the time.


Um....until we developed tools we were prey especially to the big cats on the African plains. We still are occasionally. House cats called polydactyls have one or more extra toes. These are sometimes called Hemingway cats. Often these extra digit form a unit in the place where the thumb exists in a human. We have one of these cats and have raised severe as fosters for the local SPCA. I swear they are more intelligent than your average house cat and they can use the opposable extra digits as we do an opposable thumb. Mine opens a cabinet door with them. If tigers or lions started developing extra digits like house cats I would be afraid, very afraid!


At least for the purpose of a story, I consider it perfectly acceptable to "invent" the traits and mechanics of an ecosystem to make your story work.

Because - looking at our evolution - it seems entirely arbitrary in many aspects.

Take a pack (7-15) wolves vs a large herd of prey (bisons etc.). If they had spent their "evolution mana" into intelligence, they could improve on their team play and in fact start to hunt the wolf pack down. They could maneuver - lay traps, encircle, isolate wolves - the mind game could be on. And they have the numbers.

The fact, that they usually don't fight "team work" with "team work" - IMHO stems from the fact that they have competition within the group. Any of your fellow prey getting eaten by the predator is one less competing for mating success etc.

So, in summary - the outward survival stress combined with the inward competition led to "stupid prey". "Everyone for themselves" seems to trump "Us vs them" in terms of evolution.

Just watch how some people play online team games... and how they fail and betray and abandon their allies (thanks wargaming for giving me that insight with your games) - and you know that it takes a lot of intelligence and trust, to play the game. Or - maybe - this internal competition within the prey group is also a part of us humans, in spite of our intelligence. Trivial example: Those who go to fight in a war usually do not profit from the war. Those starting a war usually do not fight and and often profit from it.


I always believe we limit ourselves in this forum by the history observed on our own planet. But it is the only model we have to consult, and the only way we are absolutely know will survive.

I agree with the idea John went with, continental division. Whether by drift or separation of disastrous cause, like an earthquake. Let’s not discount other worldly means. Maybe the predator cannot migrate north for the summer or breathe toxic atmosphere that drops into a valley for a few thousand years. I’m going to go in the opposite direction, maybe they leave each other long enough to accomplish this goal. My ideal solution would be predator that is suddenly denied access to the prey, allowing each the opportunity to develop intelligence. I always think of that as the cognizance to recognize the consequence of their actions and the actions taken against them, allowing the foresight to correct or prevent such outcomes.

Another solution that I like is the introduction of new food sources or the hunting of the slower, easier prey to extinction. Would becoming a lesser food source for a number of years allow the prey to rise to equal terms with the predator? Even if changing environmental situations never allowed the species to look for substance from each other, in the race for supremacy old grudges never really die. Hunters/hunted or not. Maybe both the prey and predatory enjoy eating the unfortunately slower new kid on the block. The prey would certainly be kicking itself when the ramifications of exhausting a natural resource took hold.

There’s no time limit involved to allow the creatures to evolve, as long as they keep their ability or social values from the destruction of each other. Your hail-mary would be a Jurassic Park that ran out a foe they underestimated. They wouldn’t have to stay toe to toe the entire time, especially if it was the predatory species that retired early.


We developed from the primates, and not from the biggest of them. Primates are not really supreme predators nor they are full prey. One important feature is the hand. You need to have a structure that can grab and manipulate tools. Another problem is that without eating meat you do not really have the energy, minerals and vitamins to develop a large brain, so I can't see how the pray would develop intelligence. I mean you could have some exotic food that provides all that, but then I can't see why they would not both eat that.

So to explain your world, you would need more then just the 2 species I guess. your 2 species would both have to develop in an area with woods, and it should be for both of them a requirement to develop hands that can help them climb. There should be other full carnivore predators, that would make their adaption of hands to climb needed. Then they evolve to also retreat in trees, where they maybe eat the strange fruit that offers all nutrition needed for large brains. The "predator" you want should be omnivore, but maybe during this initial development it would only hunt smaller pray (like birds, rats, squirrels etc). It should also be a bit bigger than the other specie. During this development stage, they maybe develop on different areas of the planet (like one in Africa and one in Europe for example if we consider Earth). Then maybe something catastrophic happens (like a super volcano) and the quantity of fruits decreases at least in one area (the predators area). This would first trigger it to hunt more, make them from "omnivore with a lot of fruits" to "omnivore mostly carnivore". As the volcano induced winter prolongs (it should be something that affects the world for thousands of years and also decrease the general flora and fauna), the predators have to migrate, at least in part, because they cannot find enough food in their area. The effects of the super-volcano must be in some way mitigated in the other area of the world (lets say there are some mushrooms that develop there that can provide enough nutrition for the pray specie).


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