Hunched in the Cretaceous grassland on a breezy afternoon, the hunting party halts a thousand yards from the Monoclonius. Downwind from the beast, they watch it graze in listless tranquility. It's a youngster of the scattered herd, some two and a half tons of grayish green bulk, and in the low sunlight the single horn on its snout casts a shadow across its face.
The hidden hunters are livid green, with dark stripes along their backs. They are bipedal, standing eight feet tall, and their four-fingered scaly hands grasp cruel spears. Unknown descendants of what future primates will call the Saurornithoides, a species of Troontid, they are the warrior caste of their cave-dwelling tribe. Eggs will be hatching soon, and there will be many hungry mouths to feed. The hunt is essential.
The horned behemoth ahead of them can't comprehend what's about to happen. For millions of years it has understood that predators may spring out of the nearby woods, and when this happens you run away. It doesn't realize that ferocious intelligence has bloomed in the late Cretaceous.
The hunters wait, keeping low in the tall grass. Suddenly a blood-chilling shriek erupts on the far side of the Monoclonius herd. A collaborating group of hunters is enacting the first phase of the plan, as they spring from concealment and charge wildly at the massive animals. Predictably, the surprise startles the herd into a panicked run.
The young Monoclonius runs at the hunters without knowing they're there. Suddenly their spears erupt from the grasses, accompanied by wild gesticulations and shrieking scaly throats. The terrified Monoclonius dashes to the side and straight into the trap.
Just a few strides in and the ground collapses. The animal's weighty bulk impales it on numerous pikes set the day before. As it bleeds to death at the bottom of the pit, the last thing it sees is a ring of snake-like heads crowding the top, hissing with victory.
When it comes to the question of when intelligent life evolved on Earth, all available data puts the answer in our family tree, sometime in the last couple million years. Human civilization is the only civilization. It is the zenith of mammalian evolution; indeed, of all terrestrial evolution.
But what if it wasn't the first civilization? What if there had been a prehuman culture in the dim days of Earth's past, while our ancestors squeaked and scurried in the underbrush?
Science fiction has dabbled in this area, from the "sleestaks" of Land of the Lost to the evolved "hadrosaurs" of a Star Trek: Voyager episode. Robert E. Howard's imagined prehistory included various reptilian beings, which, we are to believe, descended from the mighty saurians. And even science, with a measure of anxiety, has posed the occasional thought experiment on the subject.
Of course, as scientists rightly point out, extraordinary claims require extraordinary evidence. Therefore, the idea of a dinosaur civilization is less claim than opportunity for speculation, a think-tank exercise on whether or not it was remotely possible.
After all, Earthly life has existed for some 3.5 billion years. Its story is a rise and fall of various species, success and failure. Against this timeline, human civilization is a peculiar footnote. Our history is recorded to about five thousand years ago, and evidence suggests that civilization—with permanent settlements and agriculture—may stretch back to the seventh millennium BCE or earlier (Jericho in Mesopotamia and the rice/millet farms of China). By contrast, dinosaurs reigned supreme for 160 million years, the unquestionable masters of Earth and great success story of evolution. They ranged from earthshaking titans to spry egg stealers. They took to the sky and sea. They were smart and simple, fast and slow, cold- and warm-blooded.
Could any of them have created a civilization?
The very question begs another. If humans went extinct tomorrow, what evidence of our existence might survive 65 million years into the future?
Alan Weisman tackles the question in his provocative work The World Without Us. Weisman consulted a host of experts in geology, biology, paleontology, and engineering. He visited abandoned locations in Cyprus and Korea's DMZ (Demilitarized Zone) where, in just decades, nature has reclaimed the old hotels, roads, and habitats of mankind. Should humans vanish tomorrow, he concludes, nature would sweep through our handiwork with alarming efficiency. In 500 years forests would return to our cities and suburbs and consume them. The following millennia would bring glaciers to flatten our accomplishments, wind and water to erode them, and all would be done with a strange irony, for many of our newest creations would be the first to disappear into the maw of rot, rust, and entropy. Our oldest habitats and materials—think caves, catacombs, and cast iron—would stand the best chance of preservation. Long after Manhattan had collapsed, fire hydrants might be found sticking out of future grasslands and deserts.
Just how absolute our erasure would be is up for debate, and Weisman is the first to point this out. For example, it is unknown how soon plastics would break down into baser particles. The material is too new and we have little to measure it against. If the record of life is any example, something would eventually evolve to take hungry advantage of the many billions of tons of plastic our civilization has produced thus far.
Yet this is almost beside the point. If we are postulating a saurian society, it needn't be one to match our own technological one. We spent more time in the Bronze Age than the Space Age, and significantly longer in the Stone Age. The tried-and-true toolkit of flint axe and bone-tipped spear worked really well, for a really long time.
Today, museums the world over display examples of these relics. An atlatl can be unearthed after 20,000 years of burial. But after 65 million? At what point does a flint knife start to look like, well, a fragment of flint?
Is flint even a requirement of rudimentary civilization?
Definitions of civilization vary, but largely recognize it as a complex organizational system distinguished from anarchy or "rudeness." It raises its adherents above mere scavengers, grazers, or opportunistic hunters. It cultivates the environment to service its needs—crop-keeping and domestication of livestock. Free from the brutal game of daily survival, the civilized creature is free to think, dream, invent. In short, we might call civilization a form of defiance against nature.
For human beings, defiance was essential. Without claws, natural armor, or poison sacs, the naked ape seemed destined for perpetual victimhood. Life in the savannah grasslands was brutal, and all our ancestors could hope was to spot the stray hair of concealed predators in time to raise the cry of alarm. This need, as well as that of saving energy, is believed to have precipitated our habit of standing upright, which freed our hands, which led to us filling those hands with sticks and rocks . . . which ultimately led to right now.
In fact, our ancestors had only a few small advantages. They possessed forward-facing, binocular vision; dexterous digits that included the opposable thumb; strong social skills; and a relatively large brain. Without such features, shaping the terrestrial environment is implausible. To compare, dolphins and whales are highly intelligent animals but are trapped in bodies that make environmental manipulation nearly impossible. Even if we're willing to grant that whalesong is a language of sorts, our friendly cetaceans don't seem capable of producing the features of permanence we recognize as necessary to civilization: written language, shelters, farming, tool use. For another comparison, many octopuses and squid are complex and quite intelligent animals, gifted with dexterous limbs and even problem-solving comprehension. Yet with a two to five year life expectancy and a watery environment as home, the prospects of a mighty mollusk civilization look faint.
But what of dinosaurs?
With the average dinosaur brain being the size of a walnut, the prospects of a dinocivilization are pretty bleak. Science fiction has happily stepped in, particularly with regards to that Jurassic Park celebrity, the Velociraptor. "Do they show any intelligence?" asks Sam Neil's paleontologist of one of the zookeepers. The reply he gets is this stunner: "As smart as chimpanzees."
Everything we know about dinosaurs contradicts this. While a brain's soft tissue doesn't survive 65 million years, scientists have devised a way of roughly estimating the intelligence of extinct animals. They call it the Encephalization Quotient (EQ), and it provides a calculation of the ratio of brain mass to body size. For living creatures, the EQ seems to work: human beings have an EQ between 5.0 and 8.0 (interpretations of the scale vary), and the aforementioned dolphins (the bottlenosed variety) come in second-place with an EQ of 3.6. Capuchin monkeys earn a 2.5.
How about dinosaurs? Prepare to be underwhelmed: Triceratops is rated at 0.11, and the head of the class were the Ornithomimids (EQ of 0.8) and the Troodons (EQ of 0.7). The late Carl Sagan commented on this fact, saying, "I am sure that Tyrannosaurus was an efficient and terrifying killing machine. But despite their awesome aspect, the dinosaurs look vulnerable to dedicated and intelligent adversaries—such as early mammals."
Nevertheless, some scientists—even Sagan—found good reason to see promise in the brighter-than-average dinos.
In his Pulitzer Prize-winning The Dragons of Eden, Sagan writes that some dinosaur species, namely the Saurornithoides, are "interesting beasts to speculate about." He wonders, if it weren't for the extinction event, would they have continued evolving into ever more intelligent forms, ultimately resulting in a world of Saurornithoides "reading and writing books, speculating on what would have happened had the mammals prevailed"? They might have considered that "base 8 arithmetic was quite natural, but base 10 a frill taught only in the 'New Math.'"
Indeed, the entire family of Troodons shows eerie promise. Troodons possessed binocular vision, large brains relative to their body mass, flexible clawed hands with partially opposable thumbs, and lengthy arms. This promise was further explored in 1982, when paleontologist Dale Russell of the National Museum of Canada worked with artist/taxidermist Ron Sequin to invent the hypothetical "Dinosauroid." Like Sagan, the duo wanted to speculate on whether or not dinosaurs might have achieved sentience if no extinction ever happened.
The science fiction writer in me can't help but flip things around, though. I am picturing an intelligent creature in the future, long after humans are gone, finding a capuchin monkey skull and saying, "Look, its EQ was only 2.5! Given time, they might have evolved sentience, but clearly no primates ever did. After all, we have the complete collection of primate skulls: capuchin, spider monkey, lemur, and uakari. They just weren't that bright."
Clever Bird Brains
Troodons' brains put them on par with modern-day birds. So how smart does that make them?
The phrase "birdbrain" is no longer the insult it once was. Recent studies of birds show they can be quite clever and resourceful, and they even use tools. The Caledonian crow has been known to shape leaves into "hooks," which it then lowers into crevices to scoop out tasty insects. It passes this knowledge on to its offspring.
Japanese crows have gleaned a few survival habits from watching busy intersections. When traffic-lights turn red, they will swoop down and leave a hard-shelled nut on the road for cars to crack open. At the next red light, it's feeding time!
Research on pigeons has revealed that they can memorize up to 725 different visual patterns, and even employ deceit against competitors by "pretending" to have found a food source (and thereby leading other birds to the spot), only to stealthily return to the real booty. And parrots can accumulate vocabulary, and sound out words like a child.
Not bad for having no arms. And remember that Troodon had arms. Lengthy, dexterous ones at that. If a crow can go fishing with its feet, is it unthinkable that a four-fingered dinosaur with an equivalent brain and opposable thumbs could have learned to use spears?
Yet our little thought experiment is not suggesting that known Troodons ever pioneered a dinocivilization. Rather, could it be that an undiscovered relative of theirs, existing sometime in the late Cretaceous, attained sentience and the beginnings of civilization? Remember that in just a couple million years, humans distinguished themselves from the rest of the primate tree. Might not a dinocivilian have done the same . . . before the asteroid came knocking?
In an infamous argument on evolution between Simon Conway Morris and Stephen Jay Gould in Natural History magazine, Morris stated, "Contingency or no, I believe that a creature with intelligence and self-awareness on a level with our own would surely have evolved—although perhaps not from a tailless, upright ape. Almost any planet with life, in my view, will produce living creatures we would recognize as parallel in form and function to our own biota . . . were we to let evolution take another route than it did, why not grant (as, Gould will not) that another kind of being would have evolved to fill our special place in nature?"
Gould disagreed. In his book Wonderful Life, he writes, "We must assume that consciousness would not have evolved on our planet if a cosmic catastrophe had not claimed the dinosaurs as victims." The common belief that mammals were already ascending toward intelligent domination towards the end of saurian reign is a "fiction," he states. Mammals had been around since the Triassic. Small-bodied and small-brained, their ascendancy was pure chance, and Gould makes the case that if not for the extinction event our furry progenitors would still—to this day—be living in the underbrush.
However, the other side of Gould's argument is that dinosaurs would not have developed intelligence because "such a prospect may lie outside the capabilities of reptilian design." This statement seems based on the older conception of dinosaurs—that they were essentially oversized lizards. Today, it is understood that many dinosaur brains are better compared to the feathered avians.
What we know about the Age of Dinosaurs reflects only what we have found.
Our bestiary of dinosaur species is rooted in what paleontologists sift from the few fossil beds we know of. Fossils themselves are fortunate accidents, hardly the inevitable fate of bones. Paleontologists like Zhao Xijin of the China Academy of Sciences put the chances of a dinosaur bone becoming a fossil at one in a million.
The vast majority of yesterday's skeletons are lost forever, gnawed on by scavengers, broken by the elements, dissolved by soil that's too acidic, or buried somewhere far from the bulldozers of human beings. It must be accepted that our fossil collection represents a sliver of a fraction of the species that existed. It's like a great lottery game, whose ultimate prize is immortality on a museum shelf.
When new dinosaur species are discovered, it widens our view of the prehistoric world.
In the Niger desert in 2000, paleontologists Paul Sereno and Stephen Brusatte of the University of Chicago discovered two completely unknown meat-eaters. One of them had thick bony structures on its face, which Sereno believes were used in headbutting contests for dominance. Field Museum Curator Peter Makovicky commented on the find, saying, "This is an important slice in geological time, and we don't yet fully comprehend how dinosaurs on the southern continents were evolving then."
A recent find in China has been dubbed "dinosaur city" with at least 7,600 bones unearthed. Championed as the largest fossil discovery ever, it has been turning up unknown species, particularly in relation to the dinosaur-bird connection.
Our imaginations can posit an archaeological team stumbling across Cretaceous era bows and arrows, pottery, campfire sites, and crude village foundations. Perhaps like the plump "Earth Goddess" figurines of the Paleolithic, there may be a reptilian equivalent. A lone dinocivilian hunter, missing his mate enough to chisel her likeness into rock.
Every new find widens our view of the prehistoric world. Will it would ever be widened enough to suggest the above scenario?
What drives intelligence?
From our own example, it's the fact that we needed to be clever. Give us razor claws and poison glands, and perhaps the impetus for sentient evolution would never have existed.
The same seems likely in any species. Predators tend towards high intelligence (relative to their prey). Human triumph is rooted in this crafty ruthlessness. Spears were developed because they were longer than our own arms, and there was less chance of getting hurt when you could jab from afar.
Interestingly, it has only recently been discovered that spears are not exclusively human invention.
In 2005, researchers began documenting chimpanzees in Senegal making and using spears to hunt hard-to-reach bush babies. It calls to mind a story by the fantasist Lord Dunsany, in which a hunter discovered a peculiar primate which had mastered fire; as a result of this "human" behavior, the hunter decides not to shoot it.
So what about our theoretical Cretaceous hunters? If we're using our own example as reference, the progenitor of a dinocivilization would likely have been a small, swift, warm-blooded predator who could not physically compete with the larger behemoths. As with today's crows and chimps, necessity would have forced innovation. Tool-use stimulates brain development, which in turn encourages more elaborate tools. And a smaller dinosaur is harder to find for future archaeologists, less likely to leave remnants. Small dinosaurs get gulped wholesale.
Let's pretend for a moment that such a discovery is actually made. Somewhere in China or South America, a 66-million-year-old village is exhumed. Bone jewelry and possibly religious artifacts come to light. What would the ramifications of such a find be?
In short, it would be devastating to a great many fields. The notion of a "reptilian Adam and Eve" would offend the very foundation of religious sensibilities; the talking snake of Genesis is suddenly shown to have an elaborate back-story. Far from a villain coiled around the Tree of Knowledge, it is a rightful inheritor.
Scientific models of the evolution of life would have an easier time adapting, I suspect. Our idea of animal intelligence has undergone numerous upgrades in the last couple decades. Evolutionary biologists would make grudging room for a prequel tale of how consciousness arose on Earth. In fact, intelligent life blooming not once, but twice, in Earth's history would make extraterrestrial civilizations so much more likely.
Nonetheless, there would be plenty of resistance. There is something repugnant in the notion of humanity being the "second try" at civilization. It reduces us even further from our conceits. At first it was the introduction of a heliocentric model of astronomy, knocking Earth from the center of the universe. Then along came Darwin, placing us as an outcropping of the animal kingdom.
If an intelligent and village-building species were indeed discovered, now we become even less "special" by certain estimations. Some readers of Olaf Stapledon's Last and First Men are unsettled by the vast chronology he invents, and how humanity is but one of eighteen sentient varieties of mankind. Stapledon's follow-up, Starmaker, miniaturizes that immense timeline to a blip in the history of the universe. A prehuman culture would offend some in the very same way.
So, too, would the philosophical significance of sentience suffer. Why would a burgeoning civilization be snuffed out to begin with? If they could so easily be extinguished, what about us?
The idea of an intelligent dinosaur is in all likelihood a fanciful dream. Dale Russell himself said, "The 'dinosauroid' was a thought experiment, based on an observable, general trend toward larger relative brain size in terrestrial vertebrates through geologic time, and the energetic efficiency of an upright posture in slow-moving, bipedal animals. It seems to me that such speculation remains acceptable, particularly if directed toward non-anthropoid anatomical configurations. However, I very nearly decided not to publish the exercise because of the damaging effects it might have had on the credibility of my work in general. Most people remained polite, although there were hostile reactions from those with 'ultra-quantitative' and 'ultra-intuitive' world views."
There remains no scientific data for a dinocivilization. Successful as they were, dinosaurs likely failed to achieve anything resembling the technological prowess that even our Stone Age ancestors managed.
But wouldn't it be cool if we're wrong?
 History's Timeline: A 40,000 Chronology of Civilization, Jean Cooke and Ann Kramer. 1981. Grisewood & Dempsey Ltd.
 The Dragons of Eden: Speculations on the Evolution of Human Intelligence. Carl Sagan. 1977. Random House. Pg. 142.
 The Dragons of Eden: Speculations on the Evolution of Human Intelligence. Carl Sagan. 1977. Random House. Pg. 144.
 "Troodon formosus: One of the World's Smartest Dinosaurs," Tracy V. Wilson, HowStuffWorks. Discovery.com. Retrieved 2009-01-14.
 "Dinosaur Bones Find is World's Biggest, says China." David Stanway. The Guardian. Guardian News and Media. 2008-12-30.
 "Dinosaur Bones Find is World's Biggest, says China." David Stanway. The Guardian. Guardian News and Media. 2008-12-30.