To narrow this down, I'm looking only for climactic specifications. Not cultural responses, etc.

During Ernest Shackleton's expedition to the Antarctic continent, he found a huge canyon/crevasse that spanned a very large area of tectonic activity. In fact, with hot springs, volcanic activity and geysers, it remained a humid subtropical and temperate tropical version of Yellowstone or Gobustan.

This area was protected from climate changes over millions of years and still boasts the remnants of the Cretaceous Period. Due to heat from the planet, it maintains a humid and humid-subtropical climate to have allowed ancient plants and animals to thrive.

In a magnitude of order (no hard science needed), how big should my sheltered canyon or basin be, in order that Mr. Shackleton has stumbled upon dinosaurs and ancient plants, that were able to survive in a 'biome' for 66+ million years?

Post Script: I know this to be impossible; I'm asking only for the physical size, in a magnitude of order, needed to support such a large ecosystem over 66+ million years in an Alternate History story. Are we talking, "The Whole Continent," or can we have a good "Thousand Acres," et. al.

I don't care if the dinosaurs have evolved a bit. I want Shackleton to have stumbled upon a Cretaceous remnant that includes 'dinosaurs'

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    $\begingroup$ Couldn't he just stumble upon penguins? Birds are dinosaurs. :) $\endgroup$
    – Frostfyre
    Feb 27, 2016 at 18:35
  • $\begingroup$ @Frostfyre - yes of course; you know what I mean :) I wonder if the penguins have become rulers or easy fodder - that's another question :) $\endgroup$
    – Mikey
    Feb 27, 2016 at 18:45
  • $\begingroup$ @Mikey They're friends with the velociraptors, who we know from Jurassic Park are really just concerned parents that love their eggs, and are so smart they can outsmart humans in a building made by humans. I mean, it's not like they're just animals that like hunting easy-to-kill humans. $\endgroup$ Feb 28, 2016 at 2:39
  • $\begingroup$ I hope it is remembered that dinosaurs did not have scales, they had feathers. $\endgroup$ Feb 28, 2016 at 2:40
  • 1
    $\begingroup$ In a very old (sort-of) sci-fi story, it was done by making a low-lying bowl. I don't recall the details or how well it was worked out, but the lower altitude and surrounding mountains made for a warmer region. $\endgroup$
    – JDługosz
    Mar 8, 2016 at 23:04

3 Answers 3


There is no chance a reptile will be able to survive the cold of antartica - even in a sheltered valley - without some kind of heat source.

Let us assume that the valley is heated by a series of hot springs which come up and form a river which runs end to end. The heat of these hot springs can be above boiling temperature - which would provide a humid environment that can fill the open-topped valley. To prevent contamination from external organisms, the river runs out to sea via a crevasse and is dug deep into the rock with steep, sheer sides.

Looking at the dinosaur population from the point of view of a food web, your ecosystem will need some manner of food source to maintain it. It's possible that there is some sort of algae or seaweed that has evolved to live off the steam and low-light conditions of the hot springs - and perhaps some plants that were introduced in the dung of migrating dinosaurs.

For large sauropod dinosaurs, I've looked up the home range (where it browses/forages for food) of the giraffe which would have a similar diet and walking speed - and it can reach roughly 160kms (99 miles) or 25600 square km (9801 square miles).

With the assumptions:

  • the valley must be narrow enough to contain the steam
  • wide enough for any plants that need to photosynthesise to gather light
  • wide/complicated enough for herbivores to avoid predators

Your valley could be 3 miles wide and 3267 miles long. (3.737 times the length of the United Kingdom)

Picture for comparison with Australia in there for good measure:

UK, Australia and Antarctica

Remember, your valley could be wider and narrower in places, riddled with caves and be a tangled, winding shape as is natural for gullys cut by rivers. If this were the case, it could easily fit within the silhouette of the UK.

In actuality, this would not be such a stretch of the imagination and could, potentially, exist were Antarctica a little closer to the edge of its tectonic plate.

  • 1
    $\begingroup$ Like Iceland really exists. $\endgroup$
    – JDługosz
    Mar 8, 2016 at 23:04
  • $\begingroup$ Pft. Don't be silly. Who would call it Iceland? /s $\endgroup$
    – Polyducks
    Mar 9, 2016 at 10:16
  • $\begingroup$ I mean that Iceland is an example of a mantle plume hotspot that happens to be at a plate boundry also and happens to be near a pole so it's cold except where the volcanoes are. You could have somethink like yellowstone in a polar continent. $\endgroup$
    – JDługosz
    Mar 9, 2016 at 12:02
  • $\begingroup$ Oh, as for your opening paragraph, let me point out that dinosaurs did live in Antarctica, which was a rain forest, still inside the anarctic circle. There is an eposide about it in Walking With Dinosaurs. $\endgroup$
    – JDługosz
    Mar 9, 2016 at 12:06
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    $\begingroup$ The large sauropods probably gathered heat from the large fermentation vats they carried around in their bellies. Just as with modern crocodilians and giant sea turtles, there are more ways to (somehow) stabilize a body temperature and not be completely dependant on environmental temperature, other than full-out exothermic metabolism. Here is a article I found in a few seconds. $\endgroup$
    – JDługosz
    Mar 10, 2016 at 15:42

I would proceed like this:

  • Figure out what the biggest dinosaur is which you want to be found in this biome.
  • Figure out what its Minimum viable population is. (If you don't find values for this by googling it, I'd just take the largest related currently living carnivore/herbivore you can find.)
  • Calculate how much area you would need per individual of said race of big dinosaurs. (Again if Google doesn't yield anything I'd look up values for elephants/giraffes/tigers/... and scale them up.)
  • MVP times area-per-individual will give you the minimal size of your biome to support a stable long term population of your biggest dinosaur.

You can generally assume that the smaller species will need less area and can thus easily have stable populations within the same area.

  • $\begingroup$ I'd like to add to this in that you'll have to consider the space for the plants required for a herbivore to eat, then calculate how many herbivores will support a stable carnivore population and work your way through that food web for your calculation $\endgroup$
    – Polyducks
    Mar 7, 2016 at 16:46

I say the size of large city like New York or London . But that just a guess. The are numerous islands small then that and they are self sustaining. Your area would be bigger because of the need to accommodate the dinosaur.

  • 2
    $\begingroup$ Back up your claim! Any reason for this particular area? $\endgroup$ Feb 28, 2016 at 5:41
  • $\begingroup$ Why does it need to be bigger to accommodate dinosaurs? The smallest dinosaur known weighs less than 2g and is 5cm long (the bee hummingbird). You don't need a very large area to sustain a reasonable population. (If you're going to insist on extinct dinosaur lineages, then Microraptor weighed about 1kg, but of course there may be many smaller unknown ones.) $\endgroup$
    – Mike Scott
    Feb 28, 2016 at 6:58
  • $\begingroup$ @Mike Scott you assume that the dinosaur is 1 small 2 plant eating. Given the wide variety of dinosaurs they are I don't think either of us to make that assumption. $\endgroup$ Feb 28, 2016 at 14:48
  • $\begingroup$ There are some famous small dinosaurs that Darwin wrote about that are unique to a single small Galapagos island. How large are the dinosaurs you want to preserve? $\endgroup$
    – nigel222
    Feb 28, 2016 at 16:41
  • $\begingroup$ @BryanMcClure The question simply asked for conditions in which dinosaurs could survive. Since no species or types were specified, that can include small herbivorous ones. $\endgroup$
    – Mike Scott
    Feb 28, 2016 at 20:20

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