Humanity is very powerful, our simple unique trait of sapience allowed us to conquer the planet with little to almost no resistance. In the popular science fiction series Planet of the Apes; apes, with the help of disease, are able to defeat humanity once they are given sapience.

Let's assume I want to be able to easily kill humanity using a similar method. I was inspired to use the method of giving a different species sapience by Planet of the Apes. But first I must choose my species. What species, given sapience, has the best odds of defeating humanity.

Two points must be addressed to avoid over broadness:

  • The chosen species does not need to be able to defeat humanity. They just need to have better odds when compared to other species.

  • Since there are literally millions of possible species available lets limit it to vertebrate land dwellers. As they would be best able to gain this sapience.

    To address Aify's concerns by Best, I mean that the species must at least stand not only a chance but when compared to other answers, clearly has a higher likely-hood of defeating humanity.

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    $\begingroup$ Stupid second rule.... sentient amoebas would destroy the human race! $\endgroup$
    – Cort Ammon
    Commented Jun 20, 2016 at 2:11
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    $\begingroup$ This is very opinion based. How are you going to determine which answer (which I assume will all have very convincing reasons as to why it's better) is the "correct" one? As it stands now, two different answers consisting of "cats" and "dogs" are both just as valid, and have essentially the same reasons behind them. $\endgroup$
    – Aify
    Commented Jun 20, 2016 at 2:35
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    $\begingroup$ I'm surprised by your restriction to land dwellers given the dolphin conspiracy going on... $\endgroup$
    – Ludwik
    Commented Jun 20, 2016 at 6:00
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    $\begingroup$ Defend the right to arm bears.... $\endgroup$
    – keshlam
    Commented Jun 20, 2016 at 6:26
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    $\begingroup$ Humanity has a very, very good chance of defeating humanity. $\endgroup$
    – Dale Emery
    Commented Jun 20, 2016 at 8:16

9 Answers 9


If you are limiting answers to land vertebrates, then it would be rats, followed by pigeons.

Rats are smart. They can learn how to avoid almost all kinds of traps. They reproduce really fast. And last but not least, they are vectors for deadly diseases.

If they consciously put those traits to work against us, we would need to fight really hard to extinguish them. Just think of it, we hate the buggers and have failed to kill them all so far. And while it may be true that we tolerate them because it's cheaper to have things as they are now, if we were forced to fight them to extinction, it wouldn't be without huge damage to our side.

Pigeons are the closest thing to winged rats, but they don't reproduce underground. We could take them all by attacking their nests. Tough, but not as much as rodents.

Other species wouldn't fare so well against us. Amphibians and reptiles got nothing on us as it is right now. Wild mammals and birds are becoming extinct by the second. Farm animals, like cows and goats, can at best commit mass suicide and force humanity to go vegetarian or start raising lizards for cattle.

Dogs could give us a couple hours of fight, but they are easy to take down. Even if it weren't so, if they became sapient they would also have to learn how to hunt, or else they'd starve. Eating humans is a no-no, we're too hard a prey and don't reproduce fast enough to make it sustainable.

Domestic cats would fare better on getting their own food, but have you ever seen a house cat kill a human? Me neither.

If we could break your vertebrate rule, I'd go for roaches. They'd basically be rats on steroids. We can't defeat them without extinguishing ourselves in the process, period. The movie Joe's Apartment comes to mind, with its theme song that says "we have been here for a hundred million years and we'll be here longer than you!"

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    $\begingroup$ en.wikipedia.org/wiki/Giant_rat $\endgroup$
    – Fiksdal
    Commented Jun 20, 2016 at 8:02
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    $\begingroup$ "Rats are smart. They can learn how to avoid almost all kinds of traps.": This would apply to any animal if given sapience. $\endgroup$
    – user15055
    Commented Jun 20, 2016 at 9:57
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    $\begingroup$ @Stefan I agree, but rats have a headstart there. Other animals would have a learning curve. $\endgroup$ Commented Jun 20, 2016 at 10:51
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    $\begingroup$ Why would cats need to kill humans? They are perfectly fine with humans being their servants and thinking themselves smarter. $\endgroup$
    – Peter S.
    Commented Jun 20, 2016 at 12:34
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    $\begingroup$ Human could extinct any bird very quickly. A robotic gun pointing at the sky could be made buy an amateur robotician. And it is hard to hide in flight. $\endgroup$
    – Madlozoz
    Commented Jun 22, 2016 at 0:54

An Extremely Important Point To Remember

Sapience does not include knowledge or higher intelligence.

Most people, when thinking about sentience or self awareness, automatically include high intelligence to come with it as a combined package. This assumption is incorrect. We (humans) have some very dumb individuals in our society who are barely socially functional at all. Yet they are as much conscious about themselves as the rest of us are.

Now as far as self awareness goes, probably most mammals are already self aware. Many mammals have enough brains to overcome their natural drives and plan their actions by the best of their experience and skills. Dogs (specially German Shepherds) and dolphins are prime examples of that. Also don't forget the chimpanzees.

Another thing which does not come with sapience, is knowledge. When people talk about some animal gaining human level self awareness, they automatically also think they would have all the knowledge of human inventions, communication and social structures. This is not the case.

For example, a herd of wild buffaloes will only charge directly at human populations when given a motive. They would not go planned and take out military outposts at night and block the roads with jammed vehicles (dragged to the road).

Which Creature Has The Best Chance Of Defeating Humanity?

If human-level knowledge is available to the creatures, then it is definitely going to be mosquitoes. Once they have the intellect and the knowledge of the diseases they are able to spread, there's no stopping them!

At first, all of Africa will be swept clean by the pandemics of malaria, dengue and yellow fever. Arabian peninsula, Asia, South America, central America, parts of Europe and most islands would follow. While humanity will survive in far north and south, the global dominance of humans would end within a decade, if not just a few years.

Wasps and hornets also have an amazing chance at this. However, intelligent wasps would not go on an all-out war with humans and ring the alarms immediately. Instead, they would first multiply in numbers and then begin to invade suburban homes at night, one after the other. When hornets charge a house, it will be a silent, but extremely horrible raid. A thousand hornets raiding sleeping occupants of a house one night. Every human individual will be stung by 30 or more of them. Eyes, hands and throat will be the targets of stings. This will impair the ability of the target humans to:

  • use cellphones to call for medical help
  • pick up and use any available bug spray
  • breathe (with swollen throats, breathing will be extremely hard)

The morning will see corpses of horrific corpses laying around in a suburban house. It will send a wave of panic in the region, but it will only help the hornets. They will make their hives near or inside human houses so that aerial spraying of insecticide no longer remains an option. They will continue to take one locality after another until the social structure collapses and all technological advancement is reversed. Once again, humans will be able to survive in extreme latitudes, but their dominance over the planet would be over.

Rats could have had a chance, if we were living in early 20th century, but rats (or any other mammal) holds no chance. Rat holes can be easily sealed and they can be easily starved to death by keeping all food items locked and not letting them feast on wasted food scraps. Cats too, do a great job of eradicating rats from a household.

Dogs might have had a chance. But there are just too few of them. And once humans understand the threat they are facing, we would quickly and easily eradicate all of them with guns and helicopters and whatnot.

Hares could have a chance by destroying all crops worldwide and throwing the human population into a global famine. However, I wonder if hares would survive after feasting heartily on pesticide-riddled crops we have. Also, we have a good chance of eradicating feral hares with airguns, traps, hunting dogs and poisoned baits.

All in all, I think only some species of insects (or arachnids) have the potential of launching human genocides and ending their reign of planet Earth.

Edit To Add: The Killing Potential Of Mosquitoes

Some members have suggested that mosquitoes are not as much of a threat as has been declared in this answer. And that mosquito-borne-diseases have a low mortality rate.

Remember that mosquitoes already kill around 725,000 people each year. A total of around 0.2 billion people are temporarily debilitated by malaria alone. And this is for mosquitoes which do not have any self awareness and their brains have a far lesser intelligence level than a cheap cellphone.

The diseases spread by mosquitoes include, but are not limited to malaria, elephantiasis, yellow fever, dengue fever, zika fever, chikungunya fever, polyarthritis, Rift Valley fever, Ross River fever, certain kinds of encephalitis and West Nile fever.

Members claiming that mosquitoes are easily contained and exterminated should keep in mind that West Nile virus was accidentally introduced into the United States in 1999 and by 2003 had spread to almost every state with over 3,000 cases in 2006. (source). And then again, this was for mosquitoes with no sapience (as we think) and almost no intellect at all.

Mosquitoes with self awareness and social communication skills have the potential to virtually wipe out human population from their entire areas. First stage would be to multiply by at least 10 times. The second stage would simply be to infect as many people with as many diseases as possible.

The initial death toll would be around 300 million people, if not more. Furthermore, mosquitoes not only spread diseases to humans alone, but also infect cattle and other pet animals. Also, no combined, urgent, international team would be formed against this deadly threat because the governments would never know that it is not a natural mosquito infestation, but an extremely potent attack by mosquitoes.

In case of vertebrates, it would be immediately known that they are working cohesively against us (humans) and this will help making focussed decisions easy. On the contrary, even if humans do learn that mosquitoes are working collectively against us, it will take at least several years (maybe a decade), during which the losses would already be irrepairable.

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    $\begingroup$ The entire second half of this answer ignores the second rule $\endgroup$
    – TrEs-2b
    Commented Jun 20, 2016 at 6:09
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    $\begingroup$ Does indeed @TrEs-2b But considering that no vertebrate stands a chance at all ... $\endgroup$ Commented Jun 20, 2016 at 6:27
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    $\begingroup$ Other answers clearly point out how that isn't true $\endgroup$
    – TrEs-2b
    Commented Jun 20, 2016 at 6:32
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    $\begingroup$ Linnaeus used sapiens to describe humans (and only humans) to represent the unique level of intelligence that separates humans from the rest of the animals. Of course, it is also accurately used in the way you describe. Perhaps not all answers use the same definition. $\endgroup$ Commented Jun 20, 2016 at 11:19
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    $\begingroup$ There are effective vaccines and/or treatments for malaria, dengue fever, and yellow fever, all of which have a low mortality rate. Mosquitos also have fairly limited flight ranges, and a very short lifespan, making mass coordinated attacks impractical. Sorry, but we'd survive intelligent mosquitoes quite easily, although not without loss. $\endgroup$
    – Beofett
    Commented Jun 20, 2016 at 12:35

Hollywood has already shown us the way - Planet of the Apes.

Hard to say for sure which of the other primate species would be the strongest competitor for dominance, but if I had to pick one, I would go with the gorilla.

Several primate species share some important characteristics.

Upper and lower body strength and the ability to walk upright at least somewhat allows tool use, esp. when they also have opposable thumbs. Sufficient cranial capacity for higher brain function.

Respectable visual acuity, stereoscopic focus and tri-chromatic (color) vision is another advantage not shared by many other animals.

Lifespan is long enough to allow a productive lifespan even after extensive training.

They have group dynamics that support the raising of young that will be even more important with true sentience as this seems to require a longer childhood. They will naturally be able to infiltrate and grow in human society as their increased intelligence makes they valuable as workers, etc. They human-like features gives them an advantage as humans tend to have more empathy for them than other animals.

And of course, gorillas are naturals at guerrilla warfare. Yes, I know, lame, but I could not help myself.

Given high intelligences, apes would be able to successfully engage humans in warfare as they could operate many human weapons without modification. Gorillas are too large to operate jet fighters, tanks, etc. as they are designed as a tight fight for humans some other equipment require modifications too (guns where there is no room for the large trigger finger, etc.)

  • $\begingroup$ Disregarding the population of the species, gorillas do have a good chance. But considering there are only a hundred thousand of them, often in much smaller isolated colonies, I would not put too much money on them againist billions of people... $\endgroup$
    – Neinstein
    Commented Jun 20, 2016 at 8:47
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    $\begingroup$ @Neinstein - Agreed that population is against them today, that's why I posit that with intelligence, they would become workers that would grow in numbers, until the eventual revolt. $\endgroup$ Commented Jun 20, 2016 at 9:46
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    $\begingroup$ Gorillas main benefit over man is their strength... unfortunately they live in a world where warfare no longer relies on strength. $\endgroup$
    – NPSF3000
    Commented Jul 9, 2016 at 13:53

Sapience, to be effective at world domination, must be accompanied by the ability to build, i.e. manual dexterity, so I would imagine any animal with decent manual dexterity would suffice. (By decent, given sapience, I imagine a rat might be able to write and build.) They could make up for size and strength by intelligent design of machines, as humans do.

Pick an animal with an advantage over humans, for example, a much higher reproductive rate, and the combination should be convincing.


This question is a little tricky. Most animals have a pretty good sense of awareness. Dogs, cats, most other mammals, some reptiles, and some fish all have more or less the required self awareness now.

Also missing is a reason to expend all that energy. For example, let's take the dog. Why in the world would my dog want to kill me. I am it's primary source of food. It's much easier to roll-over and sit, then it is to hunt other animals. That's the entire reason that dogs are such good pets.

So to answer your question, we need a "reason" as well as a "means". There is also the issue of numbers and ability. For example a lion is a mean animal, and could easily kill a whole household of humans. But after the hunt the lion needs a long time to rest. Lions are horrid "runners", yes there fast, but if they can't eat a massive amount of food after their run they stave. So lions aren't going to be able to run much.

Finally were going to have to address adaptability. Humans can do one thing really well. That's adapt. After the first billion of us are killed by our new enemies, we will just adapt. Move to colder climates to avoid reptiles and such. What ever is going to wipe us out is going to have to be able to adapt to the different climates around the world. Not many animals can live outside a specific climate.

So what I'm looking for in a new overlord master is adaptability, large enough numbers, and some kind of "reason". I have two candidates.

Canis latrans (Coyote)

A lot like dogs, but different. These things are massively adaptable. They can live in almost every climate. They eat nearly everything. They reproduce "fast enough". They can easily kill humans. There smart, and out cities are already home to thousands of them, not to mention the ones in the wild. The can hunt in packs or alone. They are hard to see, and difficult to hunt. Now let's be clear if a military action is called against all Coyotes then there in trouble. But that's true of almost anything that doesn't violate "rule two".

What the coyote is missing is a reason. They scavenge. So just like possums or raccoons it's almost better for them if we humans keep making a mess and providing them ample food to live off of without hunting. The closest thing I can come up with for a reason is our "new" (historically speaking) desire to be eco-friendly. By producing less waste, while still living in cities were reducing their food supply. Less waste means they need to hunt more, but because we keep other animals away, they could turn to hunting us.

Ursus arctos (brown bear)

Much like the Coyote ,these things can live nearly anywhere and eat most anything. They like meat the best, but they can totally live off of veggies. There tough as hell to kill, and one could easily kill several humans. Matter of fact, the only reason they don't is because there are other food sources around. Were just not worth the trouble.

They reproduce fast enough, but they are only really in rural areas. They are much easier to spot then a coyote, but much harder to kill. Again if we figure in a military action, then there gonna have a hard time, but, once again, that's true for anything not breaking rule two.

As to reason, they already have one, and they already are a nuisance. As we expand our population centers, they get reduced area to hunt in. n rural areas this is a real problem, as, at times, they will turn around and actually hunt humans. If they were to make some kind of effort to do so on a large scale, we would be in some serious trouble. As it is now, we try to kill all of the bears that kill humans. We don't succeed. In a lot of cases we simply "give up" the area to the bear. "That's bear country, stay clear of there." If they tried to have a more focused area, they could really push us back.

A note not asked for

The largest problem for humans should an animal species decide to come at us is arrogance. We would spend, probably decades, blaming ourselves. Something along the lines of "Were the smart ones, so we should have known better then to build over their habitat. We need to do better at taking case of the ecosystem." Other ideas like "It's our job as the dominant species on the planet to make sure that our wildlife has what it need to survive. In the case of the attacking animal here we failed. We need to work together as masters of this planet to ensure that attacking animal here has enough resources to survive." It's very likely, that we wouldn't even realize that we were in a conflict, till it was far too late.



They're already on the path to world domination. An extra injection of sentience would only hasten their plans.

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    $\begingroup$ LOL Not on the path. They have dominated the world already. $\endgroup$
    – cytsunny
    Commented Jun 20, 2016 at 5:17
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    $\begingroup$ This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. - From Review $\endgroup$
    – JDługosz
    Commented Jun 20, 2016 at 5:22
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    $\begingroup$ @JDługosz The question was "What species .... " and I answered. I suppose I could have gone with Felus catus. The two criterion given were that it had to be a vertebrae land animal (check), and that it had to have the best chance of succeeding, to which I pointed out that they're already on their way, giving them quite the head start. In what way does this not answer the question? $\endgroup$
    – Cort Ammon
    Commented Jun 20, 2016 at 5:27
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    $\begingroup$ The offered buttons when voting are not always clear. Just listing a species isn't an answer; it needs elaboration. I took your second paragraph as a humorous comment, not an actual answer. $\endgroup$
    – JDługosz
    Commented Jun 20, 2016 at 5:32
  • $\begingroup$ @JDługosz: It is an answer, if not a particularly good one. As shown in the canned comment you submitted, the "Not An Answer" flag is for comments, which are pieces of text critiquing or requesting clarification from an author. Clearly, this answer does neither. Please don't misuse your flagging privileges whenever you see a short answer! You can downvote if you do not like an answer, think it insufficient etc. $\endgroup$ Commented Jul 10, 2016 at 0:22

Frogs -

Which, under the guidance of their leader "Dandelion Ponddweller of house Lillipad, first of her name, mother of tadpoles, rightful queen of the swamp, lady of the flies", could launch a single coordinated attack on humanity by poisoning food supplies and unbalancing ecosystems that would reduce the human population to a meagre fraction of its current state almost over night. And bearing in mind that she commands some of the deadliest assassins known to man, able to move almost completely unnoticed and to kill with a single touch, the stragglers would soon follow.

How then could it be anything else?

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    $\begingroup$ "Frogs" isn't a single species, although I suppose it doesn't really matter which particular species of poison arrow frog it is. $\endgroup$ Commented Jun 20, 2016 at 9:11
  • $\begingroup$ @stevejessop Yeah, I thought about being more specific but I'd have probably had to start my own "which species of frog is most likely to overthrow humanity if given sapience" question. $\endgroup$ Commented Jun 20, 2016 at 9:13
  • $\begingroup$ Except the poison arrow frogs only live in jungles, they are rare, and people have gloves. $\endgroup$ Commented Jun 20, 2016 at 12:43
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    $\begingroup$ @DonaldHobson There are plenty of ways to poison someone. Do you plan to eat later, or drink? Organising a simultaneous swim in the reservoirs supplying all of earth's major cities and larger towns would be a good start. I expect there's enough frogs for that. If not I'm sure the human-intelligence frogs will find a fun way to remedy that situation. I'm pretty certain travel arrangements would be made easy enough by that same intelligence too. Sure maybe a few frogs will be spotted and captured, but by the time the people begin to panic it will already be too late... MWAHAHAHA! $\endgroup$ Commented Jun 20, 2016 at 13:01
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    $\begingroup$ As an aside, give intelligence to frogs, and they can store up the food needed for all of their offspring, and arrange defenses as well. They technically have one of the highest reproduction rates. Just so many young are lost early. $\endgroup$
    – PCSgtL
    Commented Jun 21, 2016 at 14:50

Ants or some other form of insects, what the lack in size and strength the make up for in numbers. and it would be pretty hard for us to kill them all so even if they fail once they can rebuild and try again.

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    $\begingroup$ The second rule clearly excludes invertebrates $\endgroup$
    – TrEs-2b
    Commented Jun 20, 2016 at 3:25
  • $\begingroup$ @TrEs-2b My bad I didn't catch that part sorry. $\endgroup$ Commented Jun 20, 2016 at 3:29
  • $\begingroup$ Don't worry It's okay $\endgroup$
    – TrEs-2b
    Commented Jun 20, 2016 at 3:29
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    $\begingroup$ That's easy: as the ants develop sentience they also develop teensy little spines. Boom, crisis averted. $\endgroup$
    – The Nate
    Commented Jun 20, 2016 at 4:33

Technically we have the same Sapience of most animals on earth , +13 on the SQ scale, no more and no less ,self awareness is already the same across all mammals,reptiles and even some fish.

If you mean human-intelligence then I'd bet Rats as suggested previously.

rats mate with 500 different partners per year leaving a minimum of 2000 descendants , this number could grow up to x5 times as much if they learn to use medicines to prevent infantile deaths.

They need no training or weapons just a great determination to exterminate humans and they could take over the world before we even notice.

If you wanted to count also insects and non vertebrates then Bees could exterminate 90%-95% of life on earth in a few months because they decide if nature has to live or not.

  • $\begingroup$ There are many species of bees and other pollinating insects. If they all suddenly stop then a team of people with fluffy brushes could replace them in pollinating. It would raise food prices but not by much as brushing each plant takes seconds. $\endgroup$ Commented Jun 20, 2016 at 12:48
  • $\begingroup$ People may start in pollinating their own food as you suggested , but what about all the vegetables in nature ? they would die out causing a chain effect : plant dies > herbivore dies> predator dies and so on ... $\endgroup$
    – user21718
    Commented Jun 20, 2016 at 13:46

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