If humans didn't exist, what species would populate the earth? Would an animal gain human-like intelligence if humans weren't here? What animal would gain dominance?

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    $\begingroup$ Please define "dominant species" — is it majority of biomass (per wiki), lack of predators, or perhaps technological advance to the point of being interesting to extra-whatever life forms? $\endgroup$
    – user2510
    Oct 29, 2014 at 8:07
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    $\begingroup$ If humans never existed, or if humans no longer existed? $\endgroup$ Oct 29, 2014 at 12:48
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    $\begingroup$ There are widely-supported although not proven theories about dolphins already having a level of intelligence comparable with that of humans... $\endgroup$
    – Mints97
    Apr 19, 2015 at 21:41
  • $\begingroup$ For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much — the wheel, New York, wars and so on — whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man — for precisely the same reasons. $\endgroup$
    – Thucydides
    Feb 26, 2018 at 4:34
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    $\begingroup$ According to Red Dwarf, nuclear war wipes out all life on Earth except for fruit flies, beetles and PE teachers. Fruit flies are now the dominant species. $\endgroup$
    – Thorne
    Feb 26, 2018 at 10:34

12 Answers 12


The Raccoons

Originally a North-American species, it has dexterious hands and thumbs, can stand upright not unlike a meerkat, is an omnivore, good at problem solving and has a complex social life. These are all traits that have been proposed as crucial for the development of Homo Sapiens.

Without human existence, present-day North America is full of large herbivores, with descendants of mammoths traversing the arctic from Scandinavia through Siberia and Canada. The Raccoons spread north and live on a mixture of scavenging on large prey and hunting down smaller or weaker prey in packs. Without human interference, the next glacial period arrives when it should and allow the Racoons to cross the Bering Strait. From there they spread rapidly throughout Asia and Europe.

In Europe they become a terrible invasive species, decimating birds, amphibians and other mammals just as they have done to a lesser extent in real-world Europe today. A line of Racoons radiate out on open grass-land, either in central Eurasia or Africa and develop a truly upright posture, to better survey the land for prey and predators. This frees up their already dexterious hands and sets off a feedback-cycle between tool-use, more dexterious hands, brain development and hunting techniques.

One sunny day, a million years from now, a young inquisitive racoon is left back in camp while her family hunts. Out of curiosity or boredom, she grabs a piece of flint and slams it against a rock laying in the dry grass...

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    $\begingroup$ This answer is just fantastic. Welcome to the site Abulafia $\endgroup$
    – James
    Oct 28, 2014 at 14:11
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    $\begingroup$ Great answer. Dolphins/whales are intelligent and social, but not dextrous enough to use tools. Cephalopods are intelligent and dextrous, but not social. Both are aquatic, so tools may not even be helpful, and fire is out of the question. It's doubtful whether elephants or birds are dextrous enough. Raccoons have the full package. $\endgroup$ Oct 29, 2014 at 17:09
  • $\begingroup$ While it's an excellent answer (we had a pet raccoon when I was a child) it's worth pointing out that raccoons need some evolving before they can take over the world ("What are we going to do tonight, Rocky?") They'll need to become bipedal, and their forelegs need to become something like arms, and they need to become much more social. As it stands, they are just too small to take on large predators with stone tools, and while they can manipulate objects they have no particular aptitude for the sort of actions (throwing, for instance) which would let them effectively use weapons. $\endgroup$ Jul 20, 2015 at 15:29
  • $\begingroup$ Only if Bradley Cooper could see it :D $\endgroup$ Sep 21, 2015 at 6:18
  • $\begingroup$ Why the upright posture is that important? Of course in a grass land it helps with prey and predator, but that's a location specific thing. Or it's the location that provides better condition to intelligence grow, therefore the most adapted specie will be the most "evolved"? For instance, in a rainforest i doubt that the most efficient solution would be to have 2 hands and 2 feet, but to have 4 hands instead (bonobo)? I'm interestd in this concept. $\endgroup$
    – theGarz
    Jun 1, 2018 at 16:07

Simplified, social behavior in animals demands more brain power for memory, communication, and interactions. Who is the leader? Is Jack watching for enemies? Bob is mad at me for stealing his food.

As early hominids evolved to keep track of many members of their 'tribe,' they evolved ever-larger brains to cope with the demand.

However, social behavior alone isn't a guarantee to evolving a dominant position on the planet. There are many social animals which are quite intelligent, but obviously have not achieved the same status as humans.

Intelligence can be a naturally selected trait for solving problems, and ultimately survival. There are many theories on how human intelligence came to be.

If humans' ancestors had not existed, it's possible a different type of hominid would have risen up—literally—to take our place. Some theories of human intelligence link bipedalism, at least in part, to our success.

Perhaps one of the "most intelligent" animals on the planet would have found a niche without humans present, and evolved even greater intelligence, becoming dominant. The list frequently changes, but among them are:

  • Dolphins
  • Elephants
  • Parrots
  • Crows
  • Dogs

Perhaps it would take another few hundred million years for dolphins to become what you would consider dominant. (Perhaps that is happening anyway!)

If humans had not evolved, it's possible no other animal would ever evolve human-like intelligence. It's difficult to say if humans' presence has somehow had an effect that caused another species' intelligence to cease being a favored attribute in natural selection.

Perhaps instead, we are a catalyst for hastening the rise of a smarter species than ourselves. It may be only millennia, you see, before all the dog training we've taken part in, becomes our undoing.

  • $\begingroup$ So what, no change cats could have ruled the Earth? :( $\endgroup$
    – Cthulhu
    Oct 28, 2014 at 9:02
  • $\begingroup$ @Cthulhu: as an answer to that, I suggest the comic short story "A Dream of a Thousand Cats", which is part of Neil Gaiman's Sandman. $\endgroup$ Oct 28, 2014 at 9:49
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    $\begingroup$ Elephants are already too dominant in size, there's no reason to evolve other than to be smaller if food becomes scarce. Dolphins would need quite the evolutionary leap to get past the restrictions of being confined to water and having no limbs to create anything. Birds can fly, nothing can hurt them except other birds and clear windows, so their need to evolve is minimal. Dogs need more fingers. I think it'd have to be a primate, or something similar like a lemur. I'll go with lemurs, I like lemurs. The answer is lemurs. $\endgroup$
    – coburne
    Oct 28, 2014 at 14:36
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    $\begingroup$ Dogs only came to be after humans had already been around for a very long time. If your aim is to list animals that might have taken humans' place if humans hadn't been around, dogs don't belong on the list, although it's possible that some other canine (wolves? dire wolves? foxes?) would have. $\endgroup$
    – user
    Oct 28, 2014 at 14:37
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    $\begingroup$ @glenatron You just reminded me of something: "Dogs have owners, cats have personnel". Need I say more ? $\endgroup$
    – Tonny
    Oct 28, 2014 at 19:53

In terms of non-great ape animals (which I assume is not what you want, since they will basically just evolve into something that is, well, more or less like humans, probably… unless you're going for a Planet of the Apes-type vibe) I believe that African grey parrots are probably the closest in terms of having the “full package” towards intelligence, including a decent ability to manipulate their surroundings with their talons, with the added benefit that they can also fly! They're not quite there in terms of being able to use tools, but in terms of everything else, they're close to being “sapience-ready,” I think.

The other contender, often overlooked in my opinion, is the cuttlefish. They have a surprising number of highly-advanced mental capacities, especially considering that invertebrates are often thought of as being universally far less sophisticated or “less evolved” than vertebrates, and they have their tentacles that they can use to pick things up and move them around… plus, if you go with the cuttlefish, you can have them evolve into a Cthulhu-like or Illithid-type race, which is a cool trope, I think!

There are lots of different theories about what aspects of a creature push it more towards overall “intelligence,” as we would probably define it in a worldbuilding context. Social behaviors and ability to manipulate one's surroundings are two of the most important ones, I believe.

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    $\begingroup$ Yes! I was going to say cephalopods. Definitely the smartest invertabrates and on an evolutionary course that appears to favour intelligence. $\endgroup$
    – glenatron
    Oct 28, 2014 at 10:31
  • $\begingroup$ That's very true… $\endgroup$ Oct 28, 2014 at 11:19
  • $\begingroup$ @Glenatron And the sad thing is that they only live about two years… I feel like their culture, if and when it evolved, would be very fixated on this… a bit like Ancient Egypt, lots of R'lyeh-like undersea cyclopean mausolea, necropoli, monuments and attempts at immortality, or at least extending their lives beyond two years… $\endgroup$ Oct 28, 2014 at 11:29
  • $\begingroup$ @JoshZmijewski: chances are that evolving intelligence, which would likely require social interaction and involve teaching , would naturally lead to a longer lifespan. If not, I feel very fast-paced lives and an obsession with having a legacy everyone will remember are also possibilities. $\endgroup$
    – Alendyias
    Jul 21, 2021 at 1:18

Insects are sometimes viewed as currently dominant taxonomic group. They may have social behavior, hierarchies, bees can communicate each other the location and build relatively complex structures like honeycomb. These families may be superior to human families as they consist of big number of adult, fully capable individuals, not just of two adults and children who cannot do much.

The only problem is the small size (so limited size of the brain), but say Hercules beetle may be 17 cm long so the brain need not be very small. Titan beetle is slightly shorter but has more massive body. The problem is probably that social insects are not as big as these beetles. Also, it may possible to have distributed brain built from brains of multiple individuals, using sound or electromagnetic waves to communicate. A bee brain contains about 950 000 neurons, human has about 100 billion. 105 000 bees would be required to have the same number of neural cells. That much can easily live in just two hives standing nearby (60 000 per hive) - fully realistic.

It may be only a question of time before the nature hits that opportunity.

  • $\begingroup$ Arthropods have been around way longer than us, so probably if they had needed our level of intelligence they would have evolved it- I would think that the best chance for advanced insect intelligence would be related to a distributed colony-intelligence in social insects. Maybe also smart-shoals in aquatic animals. $\endgroup$
    – glenatron
    Oct 28, 2014 at 10:07
  • $\begingroup$ Vertebrates where human belongs originated somewhat 500 million years ago, but only as recently as 2.5 million years ago, since Homo Habilis, they started to look seriously as the origin of civilization. Arthropods may make a similar sprint. $\endgroup$
    – eigenvalue
    Oct 28, 2014 at 18:02

By the definition given here: http://www.biology-online.org/dictionary/Dominant_species, any species' "dominance" is only relative to a specified environment. A variety of animals could be considered dominant to us in their natural habitats - though if we instead define "dominance" by our ability to dominate/subdue/kill other species in their natural habitats (this seems to be the definition used by the OP and most replies here), and thus dominate those habitats that we are not native to - then I would argue that there would not be a dominant species other than us.

If we humans were out of the picture, I don't know if any other species would exhibit our "will to dominate all life". on such a scale that we could consider them to be the globally dominant species. Other species tend to stay in their own habitats, and are not likely to be able to adapt or survive outside of them. Such dominance as we have achieved would certainly not be gained by another species quickly (much evolution and learning would be required), so while an interesting question to consider, I doubt we'd ever come close to guessing the species that would evolve to our level first. Who knows, maybe a bacteria would begin wiping out enough of the life on the planet such that it would become the dominant life form by overall biomass, overall prevalence, and kill-count.

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    $\begingroup$ So evolution would not repeat itself and create another intelligent, sentient species that would dominate the planet? Didn't our ancestors tend to stay in their own habitats until they didn't? $\endgroup$ Jun 1, 2018 at 19:58
  • $\begingroup$ @TracyCramer Read my comment, specifically the second to last sentence. ;) I suggest that such evolution is certainly possible, but not something I think we should expect any time soon. $\endgroup$ Oct 12, 2018 at 14:19

I'm surprised nobody has yet mentioned rats. Just to piggyback on the reasoning of other answers, rats are social, intelligent w/problem solving skills, dextrous, and omniverous. When working together, much like we think primitive humans did, they can overcome a predator, and bring down prey larger than themselves.


Lots of neat answers here, but I would propose.. Troodude!

OK, I got that from a kids show, I don't even remember which one. It talks about a possible evolutionary progression from a particular Dinosaur called the Troodon.

The Troodon was a small therapod, possibly omnivorous. It was often put forward as an unusually smart dinosaur

The smart dinosaur theory puts forward that if they had survived the KT event, they would by know have evolved human level intelligence. The reasoning for this is that their brain in relation to body mass was unusually high. They had binocular vision based on eye placement. Their tooth shape suggests they may have been opportunistic omnivores. Their forelimbs could have easily turned into "hands" with manipulative digits.

More fanciful interpretations depict something that looks kind of like a sleestak from "Land of the Lost"

Who knows, If that little guy could have survived the KT, he may have eaten our most distant ancestors and supplanted us that way.


To slightly change the question, could an earth-like planet with slightly altered geographical/geo-historical features, themselves based on slightly different chemistry and thus climate and land-altering features, have a different dominant species? Moreover, if this species also evolved abstract science faster than we on earth and they sent astronauts to observe earth, what would this species and its proxies and assistants be? (I.e., human/dog/horse complex on earth)

I changed the question because I think a species like the feline, which clearly dominates every predatory food chain it has co-evolved with, is given short shrift on your list. Especially since otherwise worthless cats - we certainly don't breed, protect, pamper and give medical attention to cats anymore because of their rat-killing ability, in fact, that aspect of feline behavior is looked at with disgust by most modern "western" humans - are now the fastest growing mammal population worldwide, even surpassing racoons, which several of your contributors rightly pegged as another possibility.

To get to the point: a species that can enlist a species superior in some respects (let's say on their planets apelike creatures also developed spoken language) to work for them can't be counted out entirely. The ability to coerce or trick another species into helping them in very a one-sided relationship may be a better indication of evolutionary success than mere "intelligence", whatever that generalized concept means pragmatically.

Also, many niche species on earth that are not well known have developed fingers and even thumbs much like ours - certain rain forest tree frogs, for example. And the tentacles of intelligent octopi or other cephalopods could easily be surrogates for hands.

And the whole question of language implying a need for writing is also erroneous. Animals IMO can have as sophisticated a nonverbal language, based as mammals and birds clearly must be on visual images - mandalas, icons, emogees, whatever in human terms - and they could transmit knowledge and information via that language in many ways besides with fingers and thumbs.

They could have, as I indicated, if they ever needed a written language, have adopted hominid pets to do it for them, the way we adopted wolves for hunting help and horses and oxen for hard work. ( My cat forced me to write this. Actually I think dolphins are the best choi ...

  • $\begingroup$ You make an interesting answer, but I find it largely avoiding actually answering the question. As you have written it, it looks like a six paragraph long comment to another answer where just the single last sentence answer the question asked. I know you changed the question slightly, but you don't really answer the changed question either. What makes you choose dolphins as the next life-form to achieve a human-like level? They sure are clever now, but would they ever go further? $\endgroup$
    – Mrkvička
    Apr 6, 2017 at 17:55
  • $\begingroup$ I know this is years old and my comment is completely off-topic, but I love the fact that I'm reading a comment on cat answer by someone called Mrkvička with my own cat I call Mrkvička (proper name Mrkev) sitting besides me :D Sorry, I'll see myself out now. $\endgroup$ Jun 14, 2021 at 9:14

I see several answers for this, so I'll list them off.

*If only humans are taken out of the picture, then I believe it would be another hominid species, like Neanderthals, who would not have had to deal with competition from Homo Sapiens.

*If by humans you mean homonids, I believe that cephalopods would dominate the sea and either avians or felines would have dominated the land. Then, depending on how fast their intelligence grew after naturally dominating their habitats, it would either be a world of squids, cats, or birds. Or maybe evolution pulls something out of left field and we get talking horses instead. Who knows?


I think that "dominance" should be defined better, especially because it seems to be direclty linked to intelligence. It's true, we are dominant because of our intelligence but it's worth to underline that we are NOW dominant because of intelligence AND ESPECIALLY TECHNOLOGY. (a physic professor won't be really dominant if left naked in the savannah) We are dominant all around the world because of the same reasons. Dominance and intelligence are not welded together, we evolved a lot because intelligence (our main power) was/is the best tool at that/in this era. We didn't do anything "special", we didn't actually choose to be intelligent rather than strong or poisonous, it happened to be the best option and we came out on top of the food chain.

If the earth situation/climate is more or less the current one, and if by dominance we mean superior intelligence/technology, i'd go with primates or racoon as other people already explained. Otherwise, the question is not complete enough to be answered.


If "dominance" is defined by which kills off the other, then.... Whatever virus, bacterium, or fungus that (largely) kills off humanity. A future gen of a highly deadly virus like Ebola that's evolved to be airborne and thus highly contagious*; or a highly contagious antibiotic-resistant bacterium. Predicted to happen in the next few centuries.

*we've been lucky that most past microbes have been either deadly or contagious but not both. When one evolves that is both, watch out: see http://www.businessinsider.com/how-contagious-is-ebola-2014-10

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    $\begingroup$ This does not answer the question. Please edit or rephrase the answer. $\endgroup$ Nov 8, 2014 at 4:50

If by "dominance" you mean using your own intelligence, strength, mobility etc., then I don't know. But if by "dominance" you mean usurping these abilities of other species if you don't have them yourself, and controlling these abilities of other species to further your own agenda, then the answer is GRASS. What other organism has made itself so valuable to (an)other species that it uses the strength of others to clear forests to give it more living space (all the grain grasses), the intelligence of others to ward off predators/pests and to provide more nourishment (same grain grasses benefitting from pesticides and fertilizer), and even the visual/tactile tastes of others to rip up whatever else was there before and roll sod over it (your good old front lawn)?


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