How do we have so many dinosaur bones?

As someone who believes whole-heartedly in evolution, there’s something I’ve never fully understood:

When animals die, their bones decompose. If they didn’t, the woods would be absolutely full of deer skeletons, and our streets and rooftops would be covered in dead birds. This makes sense, right?

So then how do we have so many dinosaur skeletons? Do dinosaur bones not decompose?

Or, conversely, if the answer is “A very small number of dinosaur bones were preserved through unique circumstances” then how were we so lucky to find so many examples from that small number? Isn’t that a hell of a needle in the haystack?

And, not quite the same question, but related: Many ancient civilizations have myths about dragons, which are essentially dinosaurs (except for the fire thing). But we didn’t discover dinosaur bones until the 1800s. So how is it that we imagined these creatures and then discovered they were real?

Can someone explain this to me? Thank you.

butsbutts,

sorry i dunno

mulcahey,

C’mon man we’re counting on you

user134450,

extending a bit on @mustbe3to20signs answer:

here is a nice article about the total number of individual T Rexes that ever lived: nytimes.com/…/tyrannosaurus-rex-population.html

If the 20,000 number [of concurrently alive individuals] is correct, over the 2.4 million years that T. rex walked the Earth, there would have been a total of some 2.5 billion adults that ever lived.

This is for a single species of dinosaur (T. Rex)!

Next comes the question of how likely it is that a dead T. Rex leaves a skeleton that will be preserved up until our time. Fossilization requires special conditions to be present for many years following the death of the animal, otherwise the skeleton will not be recognizable anymore, after just a relatively short time (as is the case with skeletons in cemeteries for instance where you would expect decomposition to soil within a couple hundred years). Here the article has another huge number:

Only about one out of every 80 million T. Rexes that ever existed was fossilized

Those odds lie somewhere between the chance of a human being bitten by a snake and then dying from it and the chance of winning the lottery. So kind of low, but given the number of T. Rexes that lived it’s still a respectable chance.

But what about other large dinosaurs? (ignoring all species that are still around like birds and crocodiles here). If you extrapolate a little bit for the total number of dinosaur species you will soon notice that the likely number of dinosaurs that walked the earth is just so huge it boggles the mind.

from Wikipedia:

In 2016, the estimated number of dinosaur species that existed in the Mesozoic was 1,543–2,468.[25][26]

Lets round that to a nice 2000 species and assume all of those had at least as many individuals as the apex predator T. Rex (most species actually weren’t predators so their numbers would have been larger). So we get a number of 5 trillion adult dinosaurs ever. Multiply with the chance of fossilization (simplifying here by assuming the chance is the same for all species which is probably far off but hopefully we are still in the right order of magnitude).: **62500 adult fossilized individuals among all dinosaurs that lived in the Mesozoic assuming they had all very small population numbers, like the T. Rex.**If you assume larger populations, like would be expected for herbivores, you could easily get numbers that are 1000 times higher, but the uncertainty is pretty high anyway.

mustbe3to20signs,

Dinosaurs inhabited earth for almost 200 million years which translates in a gigantic amount of bones. So even if only a small percentage of these bones “survived”, there is still a lot of (mineralized) bones in absolute numbers.

Earlier civilizations also discovered them but integrated their findings with their belief system (dragons, monsters,…). It is believed that the idea of Cyclops (one-eyed giants) actually origins in the misinterpretation of mammoth skulls that have a central hole for the trunk.

XeroxCool,

It seems like there’s 10-15,000 skeletons known to exist. Is that a lot for the entire Earth with hundreds of millions of years worth of evolution and billions of different animals? It’s a needle in a haystack situation in which we’ve worked to figured out which stacks to check and how far down to go for the best odds. As far as decomposing goes, something has to do the decomposing. I’m not sure if water alone will break it’s structure like paper, but typically the work is performed by bacteria and fungi. If a skeleton is buried quickly enough without exposure and without ready access to air and water, it has a chance to essentially last forever in a dirt tomb. You can see a small scale version of this by comparing the forest to the desert. You do see skeletons out in the desert for years because they aren’t readily decomposed. Fewer organisms, less water. This tracks with most skeletons being found in drier climates - just as the classic depiction of paleontologists places them.

Another thing to consider: the organisms that feed on dead matter can’t exist until that living thing does. The organisms that eat wood didn’t exist before trees, so there was a lengthy amount of time in which trees fell and piled up without decay. Forest fires were insane by comparison. While I don’t think this is the greatest factor, a buried creature needs to be buried with those organisms to break down entirely. I don’t think we carry any of our own bone-eating organisms, so the bones stay. If they get caught in a landslide or lifeless mud or stay in a cold avalanche, some remains will be preserved.

Another source to fuel the theories and imaginations comes from imprints in the ground. Even if a body fully decays, there’s a chance it can be buried and immortalized with a stone casting of itself. This can happen with footprints and other habitual marks as well. Dinosaur Ridge in Denver, Colorado, USA has preserved dinosaur tracks from several species and what is believed to be mating dance scratches. They walked across moist clay, it dried, it got covered, and eventually it broke free. Fossilized marks like these can fill in the gaps about what dinosaurs actually looked like. If you look at the bone structure in your hand, you wouldn’t see all the skin and muscle that filled it out. A handprint would show some of that to you. If you saw a Dolphin’s hand’s skeleton, would you expect a full flipper to be covering a nearly identical structure?

Just for fun, regarding the insane scale of both life and the universe: which is oldest? Sharks, trees, or Saturn’s rings. Sharks, potentially by 100 million years. The rings may be tied with trees at 3-400 million.

Also mythical large cyclops monsters were probably based on finding elephant skulls.

Anyway, we don’t know what we don’t know. We’re making big guesses about the unknown. It may seem like we know a lot but there’s no true telling how much is gone forever, how much will never be found, and how much remains to be found

breadsmasher,
@breadsmasher@lemmy.world avatar

Dragons through history are also referenced as being giant serpents. We still have reptiles today, of which dinosaurs were similar, but in cases were very large.

Its not hard, to me, to simply assume dragons are based on scaled up “modern” reptiles rather than specifically based on dinosaurs

mulcahey,

That makes sense.

However: How come we just happened to have myths about giant reptiles and not, say, enormous dogs or cats? How did we pick the one thing that actually turned out to be real? That seems odd, right?

breadsmasher,
@breadsmasher@lemmy.world avatar

Giant mythical dogs

simplyfordogs.com/9-giant-dogs-myth-legend/

Giant mythical cats

excitedcats.com/mythical-cats-ancient-mythology/

  • All
  • Subscribed
  • Moderated
  • Favorites
  • •
  • ELI5
  • modclub
  • DreamBathrooms
  • InstantRegret
  • magazineikmin
  • cubers
  • GTA5RPClips
  • thenastyranch
  • Youngstown
  • rosin
  • slotface
  • tacticalgear
  • ethstaker
  • kavyap
  • Durango
  • anitta
  • everett
  • Leos
  • provamag3
  • mdbf
  • ngwrru68w68
  • cisconetworking
  • tester
  • osvaldo12
  • megavids
  • khanakhh
  • normalnudes
  • JUstTest
  • lostlight
  • All magazines
    •