Is it at all possible there was a civilised species on Earth long before humans?

[MBobrik]

How many million years do you think a brick building will last? How about a grass hut?

Stone tools can last as long as any other stone = indefinitely.

[MBobrik]

Now if an ancient civilization existed more like 300 million years ago, and happened to make all their cities along subduction zones, there might not be any trace left of them.

Yeah. And never build anything nor lose any tool nor leave a wrecked vehicle that can fossilize outside of a narrow subduction zone. That would require knowledge of plate tectonics and intent to hide itself deliberately from the fossil record. And they would have to start with this before they first leave the subduction zone with tools. Which is impossible because they couldn't learn about plate tectonics w/o worldwide geological research.

[Awaras]

If there was another civilisation that reached a similar tech level as us, they would have probably used up most of the oil reserves and there would be none left for us...

[Kerbface]

I'm not asking about if they could have set up oil rigs, large mining operations, skyscrapers etc., I'm just asking basic level civilisations. Maybe they lived in mud huts and their only tools were stone axes or something.

[MBobrik]

Maybe they lived in mud huts and their only tools were stone axes or something.

Then we would find their stone axes. And some huts buried under landslides, flood deposits or pyroclastic flows. And we would find their skeletons in positions that suggest deliberate burial.

[Scotius]

What about all those mountains of plastic we produce? This stuff will last a long time too.

[Kerbface]

Then we would find their stone axes. And some huts buried under landslides, flood deposits or pyroclastic flows. And we would find their skeletons in positions that suggest deliberate burial.

Possibly, though I don't see how this means it's not possible we haven't found them yet even if they are preserved. We're constantly discovering fossils of things which have never been seen before, and the fossils we do have of things which may have been very common (Like various species of dinosaur) are in very limited number, incomplete skeletons etc.. Even civilisations in some places have had very little known about them until recent history, or we still know little about them, and signs of their civilisation is largely lost or destroyed. Recently, it's been suggested a large portion of the Amazon was manmade by an ancient culture (To do with the nature of the soil), the infrastructure of which has been lost and destroyed by the jungle.

[Nibb31]

The mud or wood huts might disappear, but we would have found fossils of them by now.

At least some evidence should exist before we start making crazy hypotheses. That's how science works. Otherwise, we might as well just speculate about teapots orbiting Saturn.

[MBobrik]

Possibly, though I don't see how this means it's not possible we haven't found them yet even if they are preserved.

It is very hard to completely miss a global civilization. And we went from simple tools to a global civilization in a blink of geological time. So the hypothetical ancient intelligent species would have to be extra-ordinarily unlucky to arise just a few tens of thousands of years before a mass extinction wipes them out so that they don't have a chance to spread around the globe.

Recently, it's been suggested a large portion of the Amazon was manmade by an ancient culture.

Extraordinary claim requires extraordinary evidence.

[Kerbface]

It is very hard to completely miss a global civilization. And we went from simple tools to a global civilization in a blink of geological time. So the hypothetical ancient intelligent species would have to be extra-ordinarily unlucky to arise just a few tens of thousands of years before a mass extinction wipes them out so that they don't have a chance to spread around the globe.

I guess it depends on the nature of the culture. There are plenty of human cultures that have remained at a tribal stage up to this point in time (or at least until they began interacting with more advanced cultures). The Australian Aborigines spent some 50,000 years spreading out over the whole continent without making a single permanent structure (as far as I know).

As for the amazon thing, I'm not going to argue for it, it may be wrong, I can't remember where I learned about that.

[MBobrik]

I guess it depends on the nature of the culture. There are plenty of human cultures that have remained at a tribal stage up to this point in time (or at least until they began interacting with more advanced cultures).

Plenty but not all. And it takes just a single one.

The Australian Aborigines spent some 50,000 years spreading out over the whole continent without making a single permanent structure (as far as I know).

Left plenty of evidence like stone/bone tools and animal bones bearing tool marks, though. the only way a sentient species could go undetected is to be wiped out before having a chance to spread out of its birthplace.

[Moon Goddess]

Bones don't corrode.

As for satellites, that's a good point. The Apollo landing sites on the Moon won't be going anywhere fast. They'd be noticable too, with those reflective mirrors they set up on them. Kind of sad that it would only be proof of 1969's technology level. Do we have many more recent active probes/rovers on non-atmospheric bodies?

I was wondering about Satalites the other day when I made the mistake of watching Terra Nova, they were complaining about no way to communicate with the future, and I was thinking a geostationary sat should sit there for 65 million years ok.... I researched it but found no good numbers, saw some people saying millions of years, some saying billions, most just saying "forever (or close enough to forever that it doesn't matter)"

Stone tools can last as long as any other stone = indefinitely.

Problem with stone is, over the course of millions of years erosion does to it what it does to every stone. Just because the stone remains doesn't mean we can tell it was a tool.

I realize I'm arguing both sides of this here. Basically my point is after a couple million years it would take experts to even see a civilization. And of course our experts have looked, and seen nothing.

Here's a cool book for anyone thinking about this http://www.amazon.com/dp/0312427905

[MBobrik]

Problem with stone is, over the course of millions of years erosion does to it what it does to every stone. Just because the stone remains doesn't mean we can tell it was a tool.

.

tools that get buried won't erode.

[Cheebsta]

I get that in this case a reasonable comparison to our tech and development makes sense logically, but human knowledge versus the sum total knowledge of the universe is likely about the same as human size versus the size of the universe. Evidence that we have yet to realize as evidence shouldn't be taken off the table so easily, regardless how solid things appear. Everything we know was there for at least some period of time before we realized what it was. It is insane to think the "list" is complete.

Hypothetically speaking, a sufficiently advanced society could have seen disaster coming, and moved on. Entirely possible they scoured the planet for all items and took them along to avoid future contamination of what grew back. Yes, it is very unlikely, but is it actually impossible? Not very many things are.

[Inspector Gadget]

I'm thinking that there could've been a civilization on earth before but that would require that it was several million years ago (before 65 million years ago). Even plastic can't be presserved for that long and simple stone tools couldn't have lasted that long. Even our alloys now days would properbly have sunken in the ground by now and became chorused. Structures like Mt. Rushmore and the Giza Pyramids would've decayed so much that we wouldn't recognise them as made by intelligent life. So I'm fairly convinced that a civilisation could have existed.

They can't have evolved to our stage yet though fore more reasons:

1. If they were as advanced as we are they would've been using up oil reserves at very fast past like us. That means that if there were any other civilisation there would most likely be less oil reserves left now. This can be explained though. There could've been A LOT more oil before and they used up a big part of it, leaving what is left today. They could also have developed another way to power their machinery.

2. If they had developed space flight they most likely would've left traces on other planets and moons. Our appolo program have left a lot of traces on the moon and since there's now air out there and they have been build by some of our least corrosive materials. Just think of all the satellites there would be orbiting around our planet still if there had been any before. This could be explained by a disaster that would've wiped out, not just the earths population, but also the satellites in orbit. They could've been destroyed or flinged out of the earths sphere of influence so that we would no longer detect them. If they had left any traces on other planets like mars or venus, they would've properbly been destroyed by sandstorms, volcanic eruptions etc. I can't think of a disaster so devastating though.

3. We would need a VERY severe disaster in order to wipe out an entire civilisation like that. By that time they would proeprbly build bunkers or other safety measures that would protect them somehow, and those would most likely not decay for millions of years. The only thing I can think that could do this so quickly and devastating that they couldn't respond in time would either be a nuclear war, biological weapons or other WMDs. I'm not sure if that would actually leave any traces we would find. If didn't... it could be the cause of the last mass extinction If anyone could please verify that or prove me wrong please?

Another option would be that our planet was being engineered by a hyper advanced civilisation to sooth there needs. It would properbly change the structure of our planet so much that we might consider it a fundamental part of our planet. They could've engineered long ago to specifically make the planet habitable exactly for them and caused life on earth to evolve as it did. They could've introduced greenhouses gasses, tectonic plating... Now I'm just coming up with wild theories

[1of6Billion]

What if some sort of civilisation existed on the continent we now call Antarctica? It wasn't always our south pole.

Evidence would be hard to find. If there is anything left, not ground to dust by glaciers.

[NERVAfan]

Oh, we could probably have missed the remains of a low-tech (preindustrial) and localized civilization, if it was a long time ago... say Mesozoic...

The problem is that humans spread across the world while still Paleolithic, so keeping it localized is nontrivial.

An even bigger problem, though, is that there's nothing for them to have evolved from really. There were no really intelligent dinosaurs, judged by their brain sizes relative to body size - the smartest were IIRC about ostrich level. So we'd have to have missed not only the civilization-building species, but all the ancestors back to the equivalent of maybe when the monkey-ape-human line split from the other primates... several tens of millions of years at least.

"Ghost lineages" that long do exist for some groups, and small arboreal animals are not good fossilizers, so it's not impossible... but it does increase the odds against it.

The best bet would probably be a freakish island species that evolved on some Mesozoic island that was really far from anywhere and didn't survive to our day to have fossils, though it's hard to see a population that small and geographically restricted developing civilization.

Or a smaller-than-human entirely arboreal species that lived in the canopies of Mesozoic rainforests ... they could still make tools from wood and bone and build treehouse-huts and stuff.

But, yeah, it's pretty unlikely. Humans have become so dominant so fast...

[magnemoe]

Bones don't corrode.

As for satellites, that's a good point. The Apollo landing sites on the Moon won't be going anywhere fast. They'd be noticable too, with those reflective mirrors they set up on them. Kind of sad that it would only be proof of 1969's technology level. Do we have many more recent active probes/rovers on non-atmospheric bodies?

Bones breaks down far faster than even iron. The point is not to preserve the metal but have it turn into stone like fossilized bone. For aluminium this would probably be common as it last an very long time.

The moon landings was the largest objects put on the moon. (almost writing mun)

Has plenty of stuff in orbit but doubt it will stay for millions of years, in solar orbit it would be safe but hard to find.

[Cap'tain Kerk]

i know its not ksp related but look at this serie

http://www.youtube.com/watch?v=wSEuI3IZP-I

[lajoswinkler]

There are anthropologists who think that this did indeed happen. The Neanderthals developed tools, but then went extinct and other strains of primates took their place.

It is of course debatable if you can call all the different flavors of cavemen different species, or just different races of the same species. The line is pretty blurry in this regard.

Some anthropologists even go so far and claim that certain indigenous people, like the Aborigines or Inuit, are actually genetically so different from most other humans that they could be considered a different species. That would mean that this planet is actually shared by multiple intelligent species right now. Although this is a topic you should thread lightly on when discussing it, or you soon start to question if "human rights" actually apply to these people and you start justifying all kinds of atrocities which were committed and are still being committed against them.

Anthropology is interesting.

Those aren't anthropologists. Those are assholes who don't see beyond skull morphology and think that's the most important thing.

There is absolutely no evidence to support such statement. Humans are extremely similar at the level of genome and that's what matters. Today, because of molecular biology studies, we know even races aren't a concept that holds water in the biological sense. Two people from different "races" can be more similar on a genetic level than are two people from the same "race", which demolishes the very concept of it. The proper term is ethnicity.

Back on track, there is no evidence of any highly civilized society before humans. There were other species similar to Homo sapiens, and we've encountered them. There was even some genome mixing (I wonder what was the sex like, probably rough, LOL), but that's it. Those are the closest thing to a real race we've ever had.

Anyway, before all that mixing, before emerging from southern regions of Africa, the highest "civilization" on Earth were earlier hominids and they were not even "ooga booga" kind of guys, but dumb as rock compared to early Homo sapiens. Dumbass ape-like creatures that barely knew any tools.

Unless Earth was visited and used as a station millions of year ago by some alien species who were smart enough to avoid contamination (like we're careful about Europa and Titan), no pair of eyes ever looked into the sky and asked "who are we?". It was just eating, sleeping, f*cking, sh*ting, fighting.

As for the remnants of a civilization, if they were capable of producing concrete, which is not a terribly difficult thing to make, we'd know they exist. Concrete is durable stuff. Our skyscrapers will crumble tens of thousands of years after we're gone, but stub-like objects will last much longer. Things like reactor domes, supporting blocks for large structures, all that will outlast our species, unless we destroy it deliberately.

The only real recycler that would destroy everything on the surface of this planet is the tectonic plate subduction and that takes a long time.

[victory143]

'Insert quote of 1of6billion' Yes that could be correct, as the first land (late Paleozoic era, early Mesozoic) was squashed together in a super-continent called 'Pangaea' , so Antarctica wouldn't be that cold then.

[Diche Bach]

Not unless (a) they left virtually no record of themselves in the archaeological record, which at this point is pretty inconceivable; or ( their geographic extent was quite limited and we simply have not encountered the area where they existed.

Another issue that makes it pretty outlandish that a preceding sentient species had existed on Earth is the fossil record.

Paleontology and archaeology are all about "provenience," meaning the location of specimens or artifacts in space (lat/long/strata) and time. Hundreds if not thousands of scientists and amateurs have been collecting observations about what specimens can be found where and when for literally a couple hundred years. While there are places that remain largely inaccessible, most notably (i) the continental shelves which have been in the past, exposed by low sea levels during glaciation; (ii) areas under major ice caps (Antarctica and Greenland mainly); (iii) the deeper portions of the oceans which have been inundated for essentially the entire history of life. It is possible that all of the physical evidence for a past sentient species could be lying in one or more of these locations and we simply have not seen it. There are also areas of the world where there has been very little if any real fieldwork (major portions of Africa, South America and Asia).

The main reason that it is very unlikely that the physical evidence is out there in one of these locations and it just hasn't been found is two-fold. First, very few species have ranges that are so circumscribed that they would only leave evidence of in such pockets. Second, and this is the really biggie, the fossil record is relatively seamless and it is difficult to know where exactly such a preceding sentient species would fit in the phylogeny of the animals.

Presumably a sentient species, one that has 'civilization' as you've basically defined it, would never just emerge out of thin air (unless it came from space obviously). Sentience very likely necessitates: (a) Mammalian, or a very mammal-like reptile; ( strong mother-offspring bonding as a requisite for the evolution of complex social communication; © significant encephalization; (d) substantial capacity to develop tools, which for most animals tends to involve elaboration of distal appendages (although Crows do a pretty darn good job with their beaks too). At present in the fossil record, there is really only one 'branch' on the phylogenetic tree that shows all of these prerequisites for the evolution of civilization: the primates, and most especially the apes. Primates first appear in the fossil record about 60 million years ago, but with 'primitive' precursor forms perhaps as early as 85 mya during "Dinosaur times." Apes have only been around for about 23 my.

Its just pretty hard to imagine that a whole evolutionary lineage that culminated in a big-brained, tool-using, highly social, sentient animal would have been missed at this point because that sort of thing would have presumably left a quite large 'imprint' in the fossil record, both in terms of geographic extent and in terms of temporal extent.

Edited September 3, 2013 by Diche Bach

[Seret]

Folks, metals don't fossilise. Fossils are formed when minerals infiltrate a porous substrate. Metals aren't porous, they're crystalline. How exactly would they fossilise?

Metals sit quite happily in rock formations, that's how they occur naturally. Generally they'll oxidize all to hell, but there are some like gold that naturally occurs (and is used by us) in elemental form. All of our gold artifacts (such as components in electronics) will last pretty much forever.

[Ralathon]

If there ever was such a civilization it must've either existed very very long ago (talking permian times here) and/or never industrialized. If humanity would vanish this instant it is unlikely that any subsequent civilizations would manage to industrialize. We used up the easy oil, coal and metals. Since we had access to those resources it means previous civilizations never used them.

[Diche Bach]

A couple of other comments about hominids and other close phylogenetic relatives to modern humans.

The question of "what is a human" is really the central question in anthropology and you will get different answers from different anthropologists. As we go back in time, using the various methods at our disposal (archaeology mainly but also biological inference such as various 'molecular clock' techniques) a few things become obvious:

1. All living people today are the same species. Divisions of us into sub-types like "race" are bull**** from a scientific standpoint. If biologically valid sub-species taxonomies of modern humans were developed, there would likely have to be thousands of different categories. Race is a strictly socially constructed system of categorizing us.

2. The earliest unquestionable evidence for anatomically and culturally fully modern humans is only about 35,000 to 50,000 years ago (depending on how discerning you want to be with respect to the material evidence that shows without any doubt that modern human intellectual capacity was fully operative). Civilization (writing, cities, agriculture, social stratification, etc.) is only 6,000 to 8,000 years old, but the transition from 'pre-civilization' was likely a very gradual process, so there were long periods of time where civilization was incipient; for example, people were making extensive use of quite complex tools (including metals and pottery), people were actively engaged in domestication and exploitation of domesticated plants and animals, and permanent habitation of areas was occurring.

3. Despite this rather "recent' minimum time frame for unquestionably modern humans, we have been very human-like for a very long time. Here we start to get a bit more into the realm of opinion, but I happen to know that the opinions I will next express are not unique; other anthropologists have expressed similar things, though indeed others would disagree heartily. In my opinion, Neanderthals _were_ human (in a broad sense). They were a arctic-adapted sub-species, a real and true "race" of humanity, as different from their African Archaic Homo sapiens ancestors as any true sub-species is from another. This means that, the tropical dweling Homo sapiens heidelbergensis or however you choose to divide them up very likely would have been able to produce offspring which were at least somewhat viable. I tend to suspect that modern northern European populations have received a healthy 'dose' of Neanderthal ancestry, and I'm certainly not alone in that.

The problem with these debates is that they rage quite fiercely for decades and then some discovery or breakthrough is made and *poof* the debate is over, the final answer becomes clear. Too many 'experts' are far too comfortable expressing too strong of opinions about things that we shouldn't be in such a rush to be absolutely sure about.

4. Prior to the domination of Earth by anatomically modern humans (the last Neanderthals or other distinctive sub-species may have been as recent as 30,000 years ago), it appears that there were a number of different 'sub-species of modern or nearly modern hominids who existed during overlapping periods and probably with some degree of overlapping ranges. Some of these different species or sub-species of pre-modern humans probably fought against one another and/or interbred with one another during the last 100,000 years. These taxonomies are being debated and revised year after year and the leading expert proponents for the rival models are constantly vying for the 'consensus' in the field. Slowly, as more evidence emerges, one model may prevail. Suffice to say, oral traditions of strange not-quite human creatures like 'ogres' may have some ancient basis in our ancestors interactions with one of the other sub-species which was either driven to extinction, or partially assimilated through interbreeding or a combination of the two. Personally I tend to think it was the latter with respect to Neanderthals.

5. Now we go back to the 'pre-human' forms, which in my opinion still can be thought of as being "human" in a number of ways. Homo heidelbergensis and Homo antecessor which are probably just the far ends of a geographic cline. These guys controlled fire, made camps, probably had a fairly sophisticated communication system. True 'language' maybe not, but even Chimpanzees have an exceptionally complex communicative capacity, so it stands to reason that these guys were probably quite capable of sophisticated communication. Some populations of these guys might have been really remarkable in being gigantic in stature (2.1 meters). But on the whole, I tend to think that if you dressed up one of these guys in modern clothing and stuck him on a bus somewhere on modern Earth, and 'tutored' him/her in how to behave, he/she would only draw some very intense and uncomfortable stares. It would probably be quite obvious that they were not 'normal' but at the same time, they probably would appear to be quite 'human-like.' Whether a human mating with one of these archaic extinct ancestors could produce viable offspring (the definition of species) is a good question, but it is certainly possible. So in sum, if you accept a broad interpretation of what is human, you could even include these guys, which takes us back 600,000 years and possibly as far as 1 million.

6. Then we got the "early" Homo forms Homo ergaster and Homo erectus. Smaller brains, more robust chimplike muscultature, but nonetheless a fire controlling, stone tool making (indeed fairly 'sophisticated' stone tools, not just rocks cracked in half like the Australopithecines made), hut making, cooperative big-game hunting, Homo erectus or ergaster, dressed up in modern garb would definitely 'stick out' in a crowd but again, seems pretty dang human to me, though obviously not a full fledged modern human. Capacity for quantification, even some arithmetic? With coaching I'm sure, because even Chimpanzees can do that. Ability to recognize and use symbols, including displacement (reference things remote in time and space) and creativity (stringing together novel syntax), almost assuredly, given that chimps can be taught to do these things. But at the same time, they may have had very limited ability to perform speech as we know it, and they might appear to be pretty stupid about certain things. Generally dim-witted and dull; hell no! Chimps certainly do not appear to be dim-witted and dull, if anything it is scary how smart they are.

7. The preceding forms, the Australopithecines are intermediates between a chimpanzee like ancestors, and the more modern Homo genus. These were the first of our ancestors to walk upright. I always think of these guys as: take a chimpanzee, reshape his pelvis and lower limbs a bit so he is a more proficient upright walker, now you have an Australpithecine. It is more than just that, but that captures the essence of it. There appears to have been considerable variability in these guys which roamed all over Africa for several million years (8 or 10 mya up to 1.5mya or thereabouts). They also made stone tools, but in this case fairly simple ones: take a rock and break it a couple times, use a sharp edge to hack a leg off of a carcass. Thing here to keep in mind is: modern extant chimpanzees are EXCEPTIONAL tool makers; it is now quite clear that chimpanzees have culture, i.e., socially-transmitted traditions about how to make tools and/or do things like hunt or extract termites, etc. Language and all its associated mental sophistication are quite simply not a prerequisite for culture, although culture is more elaborated, diversified and complex in humans than in any other animal we know of. Given that modern great apes are known to be culture bearing and tool making, we shouldn't be surprised if the earliest human ancestors were also sophisticated tool users.

Lastly, I would say that, from an ethical standpoint it is very difficult to distinguish a chimpanzee or other great ape (bonobo, gorilla, orangutan) from a human. Intellectually, they are on average about equivalent to a human toddler (1.5 years roughly?) and the most exceptional Great Apes (e.g, Kanzi) are on a par with any six or seven year old human.

http://www.youtube.com/watch?v=QBlDGX95eys

Edited September 3, 2013 by Diche Bach