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Toordon Sapiens - 

Thoughts on the "Dinosaurid" 

Category: Evolution
By Brian Switek

Regardless of whether it was gradual or happened in a geologic instant, non-avian dinosaurs went extinct by approximately 65 million years ago, but the question of what they might be like today had they survived makes for some entertaining fiction. Most of such imaginary works are set on isolated islands or plateaus, "Lost Worlds" that have provided a refuge for dinosaurs - the most spectacular and enjoyable example being Weta Workshop's companion book to Peter Jackson's remake of King Kong entitled The World of Kong
Still, many of the dinosaurian hideaways do not take evolution into account, theropods, sauropods, hadrosaurs, and horned dinosaurs looking little different from what their Mesozoic forebears were supposed to have looked like during their heyday. Weta's work is a pleasant exception to this rule. There are some authors, artists, and even scientists who have pondered what evolution would have done to dinosaurs had their extinction been avoided, however, the most (in)famous example being Dale Russell's "Dinosauroid."
Unfortunately, I do not have the original 1982 Russell & Séguin paper that first proposed the "Dinosauroid" (pictured above) as a thought experiment, although today the figure is more prominent in online UFO conspiracy forums than in scientific discourse. Our awfully alien-like friend (a point I'll return to later) still crops up every now and then though, and it was a more recent television appearance that inspired me to go back and look at the bug-eyed creature that I was first introduced to during the late 1980's/early 1990's.

This brings up an important question, one that has important meaning for our understanding of evolution in general for our own history; are intelligent humanoids destined to evolve? Such a hypothesis invokes a philosophical idea of teleology, and while such a view that evolution direction (or at least inevitable outcomes) is entertained by some scientists, this type of argument is most commonly espoused by advocates of intelligent design.
Indeed, those familiar with the views Simon Conway Morris will likely recall his long-standing public feud with Stephen Jay Gould over the Cambrian fossils of the Burgess Shale and the role of contingency in evolution relating to this issue, a topic that will loom large in this somewhat cursory analysis of the Dinosauroid and it's philosophical underpinnings.
Before going into why Russell's evolved, Troodon looks so eerily familiar on multiple levels, I should reiterate what Russell has said in the past; the Dinosauroid was primarily a thought experiment in speculative biology. As he said himself in an interview given sometime in the year 2000.

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.
Even though Russell stated the Dinosauroid model is still acceptable, Russell obviously had some reservations about publishing the paper or giving too much attention to his interpretation of a Troodon 65 million years after the end of the Cretaceous. As Michael Ryan noted on his own entry on this topic on Paleoblog, a painting of a family of dinosauroids was planned for Russell's book An Odyssey in Time: The Dinosaurs of North America, and although the maquettes of the scene still exist in museum storage, the illustration was pulled from the book, a decision I think was wise - despite how interesting such a scene would be.

Still, the famous image of a humanoid dinosaur standing next to it's Troodon ancestor is a provocative one, a hypothetical relationship that confronts us with some important questions about our own evolution.
At the time Russel and Séguin formulated their hypothesis, Troodon was known as Stenonychosaurus inequalis, primarily known from fragmentary material discovered by C.H. Sternberg in Alberta, Canada. 
At that time, the material bearing the name "Troodon," were teeth initially assigned to a kind of lizard by Leidy. They were later identified to be from a theropod dinosaur, although not all scientists agreed on this until more material was discovered. Later, in 1969, Dale Russell found a more complete specimen that allowed Phil Currie to identify Stenonychosaurus as synonymous with Troodon in the late 1980's, five years after the emergence of the Dinosauroid in the public sphere. 
As you can guess, however, it was Russell's more complete Troodon that provided the basis for his speculation. This was primarily because it appeared to have a very large brain for its size, stereoscopic vision, and the first digit could have some sort of supporting role in grasping. Our problem, however, is determining just how significant each of these features are and if they really could have opened evolutionary paths up to Troodon unavailable to other dinosaurs.
The primary problem I have with the Dinosauroid and other similar reconstructions is that it rests on the assumption that a level of intelligence on par with extant Homo sapiens would have evolved in one lineage or another if hominids never evolved. How can we be sure this is so? Let's assume, just for a moment, that Troodon really did have the potential to evolve a level of intelligence within the range of Homo sapiens and survived the extinction event at the end of the Cretaceous. Would they have survived for the next 65 million years, or at least long enough to evolve a greater level of intelligence? 
There are entire groups of mammals that evolved after the extinction of the dinosaurs - mesonychids, to name one - which eventually became extinct, so our hypothetical Troodon would not have been free-and-clear during the Cenozoic. Indeed, allowing non-avian dinosaurs to survive the end of the Cretaceous would impact life on earth in ways we cannot account for. And there would be no guarantee the group would not go extinct sooner or later due to some other cause.
Given this aspect of contingency, it is difficult to be sure anything is certain in evolution, especially when the origin of our own intelligence remains mysterious. Even if we were absolutely sure of what led to the evolution of our well-developed brains, our upright posture, and other characteristics of our species, other groups of animals would not be obliged to follow precisely the same path. There would always be uncertainty in our comparisons to the hypothetical intellectual creatures. 
Convergences do occur in evolution, surely, but most of the well-understood examples - body shapes of dolphins, sharks, and ichthyosaurs as adaptations to an wholly aquatic lifestyle - do not provide good templates for the evolution of intelligence. Indeed, there's nothing in nature to suggest Homo sapiens or its equivalent was somehow meant to be or would have evolved eventually. There is no goal or endpoint to the evolutionary process and what is adaptive today might not be tomorrow. Stephen Jay Gould puts this more eloquently in an excerpt from his book Wonderful Life.

Life is a copiously branching bush, continually pruned by the grim reaper of extinction, not a ladder of predictable progress. Most people may know this as a phrase to be uttered, but not as a concept brought into the deep interior of understanding. Hence we continually make errors inspired by unconscious allegiance to the ladder of progress, even when we explicitly deny such a superannuated view of life.
As can be imagined, not everyone agrees with this view, and Simon Conway Morris has done much to speak out against the role of contingency in evolution. In a famous exchange in Natural History magazine about contingency in evolution and its relationship to the Burgess Shale, Morris wrote:

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. But first, life must arise, and we have no idea how rare an event that might be. If we are honest, despite our exciting fancies about extraterrestrials, we must admit the real possibility that life arose but once, and that we are alone and unique in the cosmos--with an awesome and, to many, unanticipated role as stewards of all other living things. But 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?
Morris' view is even more shocking when it is realized he isn't just talking about intelligence, but the entire evolutionary history of life on earth. If we were to visit another planet hosting living creatures for as long as ours, we would (in Morris' view) be able to see extant organisms similar to those on our planet and dig up alien equivalents of dinosaurs, temnospondyls, and trilobites, life following the same evolutionary pathways as on Earth. 
This seems to assume the planet on which life arose would be similar to our own, but I find it extremely presumptuous to say that life must have evolved in a manner parallel to Earth's when extinction (especially mass or catastrophic extinction) has played an important role in determining what forms of life will be present on a planet during one time or another. 
The earth is a dynamic planet, changes occurring from the level of tidal pools to continental drift, and the only way to ensure an exact parallel of evolution on another planet would be to "replay the tape" in exactly the same way to an excruciating level of detail. Gould replied to Morris' claims this way...

I am puzzled that Conway Morris apparently, doesn't grasp the equally strong (and inevitable) personal preferences embedded in his own view of life--especially when he ends his commentary with the highly idiosyncratic argument that life might be unique to Earth in the cosmos, but that intelligence at a human level will predictably follow if life has arisen anywhere else. Most people, including me, would make the opposite argument based on usual interpretations of probability: The origin life seems reasonably predictable on planets of earthlike composition, while any particular pathway, including consciousness at our level, seems highly contingent and chancy.
I don't know how else to interpret the cardinal fact that life did originate on earth almost as soon as environmental conditions permitted such an event--an indication, although surely not a proof, of reasonable expectation and predictability; whereas consciousness has evolved only once, and in a marginal lineage among so many million that have graced our planet's history--an indication, although again not a proof, that such a phenomenon is not inevitably meant to be.

Could high levels of intelligence evolved in another lineage on earth if things were different (or on another planet, for that matter)? Absolutely, but such an outcome is not automatically deigned to be. Our own evolutionary history makes it plain that the mere possession of high levels of intelligence does not grant an organism a privileged position, free from threat of extinction, our past history making it clear that evolution produces a branching bush and not a straight line of ever more "fit" forms. 

Extinction reveals the effect of contingency in evolution; why did so many of our evolutionary relatives, so close to us in form and mental ability, not survive? If we were to go back to the time when the chimpanzee lineage and the line leading to Homo split and started over again, would we have reached the same outcome? Would another relative of ours, perhaps Neanderthals, survived and developed in a similar way? This is a game of "What if?" that I have no answer to, but it seems clear that high levels of intelligence are allowed to evolve and are not an unavoidable consequence of the evolutionary process.

Returning to the subject of our friend the Dinosauroid, such reconstructions seem to reflect the sort of progression seen in the above illustration of horse evolution. It's easy to pick what may seem like a suitable ancestor and bookend an arrow with a living descendant, but there is a lot of evolution in that arrow which is omitted. This illustration, for one, suggests once Eohippus evolved, it was on the fast track to becoming Equus. The transitions in-between like the growth in size and reduction of toes being intuitive, and it seems the Dinosauroid is based upon the same sort of logic which largely disregards the way evolution works. 

In a way, such reconstructions even represent a kind of special pleading, not only implying the survival of a particular species but also clearing the evolutionary path for it to evolve in one way rather than another, in this case taking the form of a human. Even if we are to play along with this idea, would highly intelligent creatures converge on a humanoid body form (as Morris suggests)? Again, not necessarily, and there's no reason to think that high levels of intelligence must be accompanied by an upright, bipedal stance, opposable thumbs, or an overly large braincase. As Darren Naish once wrote on this same topic.

The reason that we humans have the body shape that we do is not - I think - because it's the 'best' body shape for a smart, big-brained biped to have, it is instead the result of our specific lineage's evolutionary history. Given that, so far as we know, the humanoid body shape has evolved just once, we simply have no way of knowing whether it's a particularly 'good' morphology or not. Furthermore, the humanoid body shape is not a prerequisite for the evolution of big brains given that brains proportionally as big as, or bigger than, those of hominids are found in some birds and fish (that's right: humans do NOT have the proportionally biggest brains).
The morphology of Homo sapiens has some advantages (energy efficiency when walking long distances) and some drawbacks (convoluted, narrow birth canals and back pain/injuries), but I don't think that we can objectively call it "good" or "bad," either. Thinking that intelligent organisms must adhere to our shape does little except highlight the hubris that often goes into such considerations. I had mentioned before that the Dinosauroid has appeared more often in tabloid newspapers and alien internet forums than scientific papers, and this is primarily because it looks like the stereotypical alien, itself a sign of bias on the part of our own species. As Carl Sagan wrote in The Demon Haunted World...

The typical modern extraterrestrial reported in America in the '80s and early 90's is small, with disproportionately large head and eyes, undeveloped facial features, no visible eyebrows or genitals, and smooth gray skin. It looks to me eerily like a fetus in roughly the twelfth week of pregnancy, or a starving child. Why so many of us might be obsessing on fetuses and malnourished children, and imagining them attacking or sexually manipulating us, is an interesting question.
...the UFO abduction syndrome portrays, it seems to me, a banal Universe. The form of the supposed aliens is marked by a failure of the imagination and a preoccupation with human concerns. Not a single being presented in all these accounts is as astonishing as a cockatoo would be if you had never before beheld a bird. Any protozoology or bacteriology or mycology textbook is filled with wonders that far outshine the most exotic descriptions of the alien abductionists. The believers take the common elements in their stories as tokens of verisimilitude, rather than as evidence that they have contrived their stories out of shared culture and biology.
Oddly enough, it is often birds, the descendants of dinosaurs, that often show us  animals with high levels of intelligence do not have to be upright apes, or even primates. Alex the African Grey Parrot (who recently passed away) possessed extraordinary cognitive abilities, and it has long been known that members of the Family Corvidae (i.e. crows) are extremely intelligent, having brain sizes comparable to that of chimpanzees, dolphins, and humans. 
Even in turning to non-human primates, Capuchin monkeys have brain-to-body size ratios on par with those of chimpanzees, the New World Monkeys proving to be very intelligent even though they might not be immediately recognized as such as they are arboreal quadrupeds and not apes. Truly, the more animal cognition and intelligence is studied it seems that some have minds that are far closer to our own than we acknowledged previously.
Finally, this brings us to the birds. Troodon was closely related to birds and likely had feathers, but by the time it existed in the Late Cretaceous, there were already avians in the air. Even if Troodon survived, would birds have developed higher levels of intelligence first? 
What if both dinosaur and avian did? It is clear from living species that many birds have high levels of intelligence, however, and so we can say dinosaurs did evolve high levels of intelligence but look nothing like Homo sapiens, refuting the Dinosauroid model. This becomes immediately apparent when we stop considering ourselves as privileged or superior to other forms of life on this planet, leaving us no reason to think that there is some universal constraint that only also primate-like organisms to achieve intellectual prowess.
At this point, I should probably mention the fantastic artwork of Nemo Ramjet, an artist who's Dinosauroids are probably more accurate when considering if dinosaurs were able to evolve higher levels of intelligence. As I've attempted to make clear in this post, however, there's no reason to believe that given a reprieve from extinction at the end of the Cretaceous non-avian dinosaurs would have evolved in such a manner at all (Dougal Dixon's The New Dinosaurs springs to mind here, although it's guilty of supposing fine-tuned convergence in many cases, as well), such a change in history having no set outcome and still being subject to contingency. 
The extinction of so many of our own evolutionary relatives like Paranthropus show that intelligence does not provide an evolutionary free ride or have inevitable consequences, making the development of intelligence all that more special and rare. As fulfilling or enjoyable as it may be to construct evolutionary narratives to elucidate how evolution made us what we are, we should not attribute the role of "Mother Nature" to evolution; nature neither cares for us or despises us, and it is that fact that makes our present condition all the more spectacular and valuable.


Brian Switek is a freelance science writer specializing in evolution, paleontology, natural history, and the history of science. He blogs regularly at WIRED Science's Laelaps and Smithsonian magazine's Dinosaur Tracking.

How Intelligent Dinosaurs 

Conquered the World

by Darren Naish
Maybe it's because I write too much, but I am frequently surprised and sometimes a little freaked out at the strange coincidences that have so often cropped up during my time here at Tet Zoo. Long-time readers will recall the several occasions when we've looked at hypothetical intelligent dinosaurs: it started back in 2006 with my contention that ground hornbills (bucorvids) should be regarded as the dinosaurs most convergent with hominins (here). Humanoid dinosaurs like Dale Russell's hypothetical big-brained troodontid - the 'dinosauroid' - are (in my opinion) utterly unrealistic, relying more on the notion that humans are the bestest animals ever, rather than on what we might really infer from dinosaur evolution. Inspired by all of this, my good friend Nemo Ramjet (blog here) designed a new-look dinosauroid, the bucorvid-like post-Cretaceous deinonychosaur Avisapiens saurotheos (here). Nemo went on to create a culture and society for Avisapiens, with cave art and everything (here)...
erhaps partly because of this - but partly because of coincidence - two new articles have recently appeared on big-brained hypothetical dinosaurs. The first was by Jeff Hecht: Jeff is best known in the zoological world for the reporting he does in New Scientist on new palaeontological discoveries, but he's best known globally (so I understand) for his writing on lasers and fibre optics. Jeff's new article (Hecht 2007) highlights the fact that, 25 years on, palaeontologists are still interested in the thought experiment initiated by Russell & Séguin (1982), but think that 'Russell's dinosauroid needs updating'.
Jeff spoke to theropod expert Tom Holtz, who is quoted as saying that the dinosauroid looks too human, and that - if troodontids were to evolve primate-like braininess - they would retain the long tail and horizontal body posture common to theropods (Hecht 2007). This might sound familiar, because it's the same argument I used when writing about dinosauroids at Tet Zoo. 
I'm not implying Tom stole my idea: he probably thought these thoughts before I did. I'm also quoted in the article, again making the point that, if theropods were to evolve big brains and sentience, there is no reason other than anthropocentrism to think that they might resemble us physically. Exhibit A: parrots.
second article, this time on the subject of brain size and intelligence in dinosaurs, appeared in a 2008 issue of the Czech magazine Svĕt. The article, by Vladimír Socha (and written in Czech of course), includes a discussion of hypothetical intelligent dinosaurs [this section shown below], and what will interest Tet Zoo readers in particular is its reference to Nemo's Avisapiens. This is the first time Avisapiens has appeared in print if, that is, you don't count Nemo's portfolio (available here).
McLoughlin's Bioparaptor
In another curious and totally unconnected coincidence, Tet Zoo regular Steve Bodio (ofQuerencia) recently sent me a copy of an article that I was totally unaware of: John C. McLoughlin's 'Evolutionary bioparanoia', published in Animal Kingdom magazine in 1984. Most of you will know of John because of his 1979 book Archosauria: A New Look at the Old Dinosaur(less well known is its 1980 follow-up Synapsida: 
A New Look into the Origin of Mammals). Written back when everyone was getting all excited about Robert Bakker's dynamic, hot-blooded view of the dinosaurian world,Archosauria was one of the first works to visualise dinosaurs as active, alert animals with boldly patterned, sometimes feathery, bodies. John depicted his dinosaurs chasing, trotting and foraging, and many were much-copied by other artists and proved highly influential (many of the dinosaurs in David Lambert's 1983 Collins Guide to Dinosaurs, for example, are copied from those that appeared in Archosauria).
John's 1984 article describes his contemplation of a new psychiatric disorder he recognises in himself: evolutionary bioparanoia. It is 'an acute, often immobilizing sense of dread generated by fatigue in persons interested in both the current state of world affairs and the evolutionary history of life on Earth' (McLoughlin 1984, p. 25). 
The article begins by considering the probable short lifespan of technologically advanced societies, the (alleged) short-lived nature of anthropogenic artefacts, buildings and other constructions, and the fact that humanity's rise to global dominance and massive impact on the global biota will be all but geologically instantaneous. 
John notes that, in a global biota with a horribly impoverished large animal fauna, the most abundant large non-humans animals are domesticated cattle. We imagine what non-human geologists, living in the far distant future 60 million years hence and looking back at the Holocene fossil record, will see if human society obliterated itself by way of nuclear war. A layer of unusually concentrated elements; massive erosion caused by agriculture and war; a time of massive dying.
Here's where the evolutionary bioparanoia kicks in. Noting that this sort of thing is, pretty much, what we see in the fossil record of the latest Late Cretaceous, John explains how comparatively big-brained maniraptorans like the dromaeosaurs might perhaps have evolved their very own sentient tool-maker. 
Ladies and gentlemen, I give you McLoughlin's smart tool-making maniraptoran, yet another hypothetical big-brained sentient theropod. He doesn't name it, but I'm going to call it Bioparaptor macloughlini (bioparanoia + raptor, 'macloughlini' isn't a typo: the ICZN recommends that 'Mc' spellings become 'mac-' names).
Depicted as a swell-headed deinonychosaur that wears jewellery and has invented nuclear weapons, Bioparaptor recalls Russell's dinosauroid in having a short-jawed, big-brained skull and in having lost its pedal sickle-claw, but differs from it in being long-tailed and overall more dinosaur-like. Its nefarious activities not only resulted in a nuclear conflict that caused the end-Cretaceous event, but its domestication of herding cattle-like herbivores (Triceratops and kin) resulted in an impoverished terrestrial fauna where other big animals were rare or absent. 
I'm shocked no-one has brought this to my attention earlier, and am surprised that John's Bioparaptor hasn't been mentioned more often. McLoughlin (1984) makes no mention of Russell's dinosauroid (published in 1982): while I'm sure John was aware of it, the fact that Bioparaptor looks so different implies it 'evolved' convergently, the product of a different thought experiment.Magee's Anthroposaurus sapiens
Moving on, here we come to the next coincidence as, while working with Jeff Liston in Glasgow's Hunterian Museum during November 2007, I learnt that views essentially identical to those expressed by John had managed to get into the non-fictional literature elsewhere, thanks to an obscure little 1993 tome by one Mike Magee, titledWho Lies Sleeping: the Dinosaur Heritage and the Extinction of Man. Thanks to Jeff, I've since gotten hold of this book.
t's very weird. As in McLoughlin (1984), the main thrust here is that sentient, big-brained dromaeosaurs - Magee calls them Anthroposaurus sapiens - evolved at the end of the Late Cretaceous and, via industrial pollution and a nuclear war, caused their own extinction as well as that of many of their contemporaries. 
On the way, Magee stops to look at Elaine Morgan's aquatic ape hypothesis - I'm still not sure why - and generally agrees with it. He also spends a chapter examining the evidence for evolutionary saltation and super-rapid evolution (Magee 1993). He's a big fan of Bakker's The Dinosaurs Heresies and Desmond's The Hot Blooded Dinosaurs. In fact, they seem to be about the only dinosaur literature he cites. It is proposed that anthroposaurs evolved from arboreal primate-like theropods and, like the aquatic apes of Morgan's AAH, they went through an aquatic phase and hence convergently became human-like.
In McLoughlin (1984), it is suggested that the low-diversity ornithischian assemblage of late Maastrichtian North America reflects the fact that the smart dinosaurs maintained Triceratopsand Edmontosaurus as domestic animals: 'herded on the great plains before being shipped to a Cretaceous Chicago for making into meat pies and hamburgers' (Magee 1993, p. 110). 
Anthroposaur industry resulted in the evidence for iridium concentration, acid rain, rising global temperatures and so on seen in the late Maastrichtian record, and it is suggested that some dinosaur lineages actually evolved to cope with the chronic atmospheric pollution that resulted. Here we have the explanation for the elaborate cranial crests of lambeosaurs, the convoluted nasal passages of ankylosaurids and the big nose of Altirhinus - which wasn't Maastrichtian, but let's not worry about that
The nuclear war that finished off anthroposaur society explains the evidence for global wildfires, the bits of stressed quartz and the tektites interpreted by others as evidence for asteroid impact. Mummified dinosaurs - like Sternberg's famous Edmontosaurus from Wyoming [shown left] - surely owe their remarkable preservation to this global nuclear conflict. I think my favourite sentences in the whole book are 'Dinosaur mummies are rare, but when found they are usually late Cretaceous hadrosaurs. Why should they have died so perfectly and been preserved? Because they died of gamma radiation and neutrons which preserved them as surely as it would preserve strawberries in a plastic bag?' 
qually if not more entertaining is Magee's suggestion that the various man-like tracks reported from the Mesozoic are not the distorted genuine tracks, amorphous holes, or blatant fakes which examination has demonstrated them to be, but are instead actual anthroposaur tracks.
he book's title refers to the idea, loosely 'explained' in the very last chapter, that anthroposaurs lay sleeping, though whether this is meant literally (that they are hiding under the ground) or figuratively (that they are somehow within our psyche) is never made clear. It might be both, as he writes of Typhon, Echidna, Tiamat and the serpent from the Garden of Eden as if they and other mythological semi-reptiles might be racial memories of smart dinosaurs. 
And of course, there's the fact (I use the term loosely) that H. P. Lovecraft had a telepathic connection with anthroposaurs, and this 'explains' his references to the Old Ones, the fallen city of R'lyeh, his loathing of immigrants, desertion of his attractive wife, and poekilothermic physiology. ...Err, yup.  
Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Portsmouth, UK) who mostly works on Cretaceous dinosaurs and pterosaurs. He also studies such things as theswimming abilities of giraffes and fossil marine reptiles. An avid interest in modern wildlife and conservation has resulted in many adventures in lizard-chasing, bird-watching and litter-collecting. I've been blogging since 2006 and a compilation of early Tet Zoo articles is now available in book form asTetrapod Zoology Book One. Additional recent books include The Great Dinosaur Discoveries and Dinosaurs Life Size

But just suppose...
What if the asteroid had missed?
By Georgie Hatt-Cook, Via BBC Horizon

Dinosaur feeding bowl (BBC)
It could have all been so different...
The extinction of the dinosaurs was most probably caused by an asteroid hitting the Earth - but what would have happened if the giant space rock had missed?
For a long time it was thought that dinosaurs were a lumbering, cold-blooded extinction just waiting to happen. Even the word dinosaur has come to mean something that has outlived its time.
The scientific argument was that as cold-blooded creatures, dinosaurs would not have stood a chance of surviving an ice age.
"According to the first imaginings of palaeontologists and the general public about dinosaurs, we thought of them as reptiles," says Kristi Curry-Rogers, from the Science Museum of Minnesota.
"'Reptile' is a word which comes with a lot of other connotations, like cold-blooded, slow-moving, sprawling, scaly skins, kind of stupid."
But more recent discoveries, such as dinosaur fossils in both polar regions, reveal that these animals were far more adaptable than previously thought.
Dr. Curry-Rogers has analysed fossilised bones from Late Cretaceous (65-99 million years ago) dinosaurs and found them to have more in common with mammals and birds than reptiles.

 They were the superlatives; they were the biggest, the heaviest, the meanest, the longest. You name it, dinosaurs were it. 
Prof Phil Currie, University of Alberta
The evidence points to them being fast-growing and, crucially, that at least some of them were warm-blooded to some degree.
"They were perfectly well-adapted to deal with the problems of maintaining a body temperature," Dr Curry-Rogers told the BBC's Horizon programme.
In other words, some of the dinosaurs were more than equipped to survive almost anything that the evolving planet had to throw at them.
Ongoing domination
"They were the superlatives; they were the biggest, the heaviest, the meanest, the longest. You name it, dinosaurs were it," says fellow palaeontologist Phil Currie, from the University of Alberta in Canada, who has access to one of the richest areas of dinosaur research in the world.
"The badlands of Alberta clearly show at the end of the Cretaceous, dinosaurs were extremely successful still," says Professor Currie, who points to dozens of different dinosaur species living in that one environment at the same time.

Had the asteroid missed, he believes, dinosaurs would have continued to dominate.
"We wouldn't have the modern animals that we're used to. Giraffes and elephants and so on; they just wouldn't have evolved because dinosaurs would still be here," says Professor Currie.
Instead of elephants, there would be large plant-devouring sauropods. In place of lions on the plains of Africa would be tyrannosaurs.
Adaptable dinosaurs had it all covered. Dinosaurs could have comfortably colonised many environments, from polar conditions to regions of rivers and forests, jungle and deserts.
A world with dinosaurs in it would be at the expense of most, if not all, of the mammals that we are familiar with today - and all that we rely on them for. No cows, no sheep, no cats equal no milk, no leather, no wool, no domestic companionship.
But milk aside, there could be perfectly suitable dino-substitutes of all kind. A Protoceratops could be as farmable as a pig with the bonus of providing eggs. And an amenable Heterodontosaurus might make a perfect pet. Great with children.
They could even have adapted to current-day habitats, dining on suburban dustbins.
Something like us
Perhaps the most advanced dinosaur at the time of the extinction was the Troodon which was "as cunning as a fox", according to palaeontologist Larry Witmer of Ohio University.
They were small, upright, bi-pedal dinosaurs which lived in large groups. By studying the brain cavity, Witmer has found evidence they possessed good vision and even potentially had a brain structure compatible with problem-solving.
"ITroodon were around today, co-existing with humans, we'd probably call it a pest," says Professor Witmer.

Dino outside a house (BBC)
It's unlikely mammals and dinosaurs could have shared power.
With its substantial brain, long grasping hands and big eyes, could Troodon have evolved to become more intelligent?
Evolutionary palaeo-biologist Dr Simon Conway Morris believes they could even have evolved along the lines of primates or humans.
"The human is extraordinarily well designed," he says. The whole arrangement is actually designed for a particular mode of life, which, as you can see looking around us, is incredibly successful.
"If it's such a good solution for us, is it so difficult to imagine it could be a good solution for a dinosaur, therefore a 'dinosauroid'?"
But most palaeontologists see the dinosauroid as an insult to dinosaurs.
"Dinosaurs probably would have continued along their dinosaurian trajectory, getting bigger brains and bigger eyes," says Kristi Curry-Rogers. 
"But I doubt seriously that any dinosaur would ever end up looking like a person, and it is fairly arrogant to think that the end point of all evolutionary trajectories should sort of emulate human beings."
If the asteroid had missed, there probably wouldn't be humans here today either to find out how it would have turned out.
The impact that ended the golden age of dinosaurs 65 million years ago made for an extremely bad dinosaur day but it was also a very good mammal day.

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Only 26 days until Hallowe’en!

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