# dinosaurs and humans **URL:** \ **Category:** Factual Questions\ **Created:** [July 2, 2004, 7:31am UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196 "2004-07-02T07:31:35Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Jeffro](https://avatars.discourse-cdn.com/v4/letter/j/7993a0/32.png) [@Jeffro](https://boards.straightdope.com/u/Jeffro)\ **Post date:** [July 2, 2004, 7:31am UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/1 "2004-07-02T07:31:35Z")
I’m currently reading the Eden series by Harry Harrison. This takes place in an alternate reality where the comet that killed off the dinosaurs never happened. So in the book, humans have evolved in a world where all the big dinosaurs still exist. Could something like this have happened or did we need to get rid of the dinosaurs to get to become successful as a species. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [July 2, 2004, 7:43am UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/2 "2004-07-02T07:43:10Z")
I think the demise of the dinosaurs was the big break for the mammals; certainly things would be _different_ if they hadn’t become extinct (in fact the dinosaurs themselves would be different too, because what we see in the fossil record is just snapshots of something that was continually changing). There probably wouldn’t _be_ humans under those circumstances, but the same could be said about any change of circumstances if it happened early enough. Someone will no doubt point out that we _do_ share our world with dinosaurs (or their descendants) - birds. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [July 2, 2004, 10:39am UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/3 "2004-07-02T10:39:12Z")
Honestly the question is impossible to answer factually. There were a huge number of improbable events that went into producing Homo sapiens, just as there were for any other species. Because the events were o improbable you find yourself in the same situation as Homer Simpson and his time travelling toaster. Any tiny change in circumstances would almost certainly have prevented H. sapiens from evolving. That isn’t to say that other intelligent mammals wouldn’t have arisen, just that they wouldn’t have been us. There were already a surprisingly wide range of animals living alongside the dinosaurs, but mostly insectivores. There is no particular reason to assume that they would not have gradually radiated into groups similar to most of what we have today even if the dinosaurs hadn’t died out, but the exact dynamics would never have been the same. There is no particular need to get rid of the dinosaurs for hominids to become successful any more than we needed to get rid of elephants and tigers. As a result mammals may well have evolved into something similar to apes and it’s theoretically possible for intelligent apes to have come about, but the chances of exactly the same steps occurring would be staggeringly small. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [July 2, 2004, 11:25am UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/4 "2004-07-02T11:25:41Z")
A paleontologist once said that you could fit all the mammal skeleton fragments recovered this far from the Age of Dinosaurs in a shoebox. Having just been to the Smithsonian Natural History Museum last week, I can believe it. It’s an acknowledgment of both how rare and how small those fragments are. It wasn’t until the dinosaur competition got offed that mammals had a chance to blossom. ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [July 2, 2004, 12:24pm UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/5 "2004-07-02T12:24:21Z")
As I understand it, only the big dinosaurs died out. Little dinosaurs are still around – we usually call them “birds”. But it does seem that the big dinosaurs becoming extinct left room for little dinosaurs and little mammals to evolve. ---
**Author:** ![wisernow](https://avatars.discourse-cdn.com/v4/letter/w/13edae/32.png) [@wisernow](https://boards.straightdope.com/u/wisernow)\ **Post date:** [July 2, 2004, 2:16pm UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/6 "2004-07-02T14:16:00Z")
Dinos would have evolved as creatures with more intelligence than man and would have made us their slaves. Dino to me - Turn around, it’s your turn today… :eek: ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [July 2, 2004, 2:16pm UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/7 "2004-07-02T14:16:44Z")
> [@CalMeacham](#): > > A paleontologist once said that you could fit all the mammal skeleton fragments recovered this far from the Age of Dinosaurs in a shoebox. Having just been to the Smithsonian Natural History Museum last week, I can believe it. It’s an acknowledgment of both how rare and how small those fragments are. It wasn’t until the dinosaur competition got offed that mammals had a chance to blossom. Well said, **Cal** – though developments since have produced a **lot** more fossils from the Late Cretaceous (100-65MYA), when placentals and marsupials were beginning to radiate. Contrary to the “competition” and “Mesozoic mammals rare” allegations, though, the fact of the matter seems to be that mammals in the Mesozoic were not at all uncommon, but restricted by the simultaneous evolution of the dinosaurs to the smaller-animal econiches. By the time mammals had gotten their evolutionary act together and produced the adaptations that made them successful in the Cenozoic, the large-animal econiches were quite well filled by a wide variety of well-adapted dinosaurs. There was, however, quite a lot of competitive room for furballs in the small scavenger/insectivore/fructivore ecoranges, where the competition was mostly various lepidosaurs without the mammalian or dinosaurian advantages. The largest Mesozoic mammal seems to have been a multituberculate about the size and lifestyle of the woodchuck. The reason for the paucity of mammalian fossils under this interpretation would lie in the relative unlikelihood of very small bones and teeth being preserved, as opposed to the much larger remnants of dinosaurs, which were relatively less likely to be destroyed by normal taphonomic processes. After the K-T transition, the larger-body econiches were pretty much wide open, and mammals, birds, and crocodiles competed for them, with mammals eventually occupying the vast majority of econiches. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [July 2, 2004, 2:18pm UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/8 "2004-07-02T14:18:17Z")
> [@Polycarp](#): > > Well said, **Cal** – though developments since have produced a **lot** more fossils from the Late Cretaceous (100-65MYA), when placentals and marsupials were beginning to radiate. Eep… that was meant to mean “developments since that quote was made” not “developments since **Cal** went to the Smithsonian last week,” of course! :o ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [July 2, 2004, 2:36pm UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/9 "2004-07-02T14:36:42Z")
> [@](#): > > Eep… that was meant to mean “developments since that quote was made” not “developments since Cal went to the Smithsonian last week,” of course! Well, you know how fast science moves these days… ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [July 2, 2004, 5:29pm UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/10 "2004-07-02T17:29:11Z")
Yes, I’ve always believed that if a worldwide cataclysm had wiped out our reptilian ancestors, maybe today’s dominant species would be silly little mammalian bipeds, rather than us. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [July 2, 2004, 5:30pm UTC](https://boards.straightdope.com/t/dinosaurs-and-humans/253196/11 "2004-07-02T17:30:34Z")
Oops, right thread, wrong continuum. Sorry.