The basic idea is that a massive organism with a bone structure similar to a tortoise's dies in an open area. Then, once only bones are left, they become an open cavern with fertile soil layered on the bottom. How long might these bones last in the environment described below?

On a world similar to Earth minus size, gravity, and a mildly different atmosphere. The weather is much more violent, causing frequent dust storms. The planet is larger than Earth and is mostly scrublands. However, there are certain geological formations, bowl mountains, that provide adequate shelter for forests. There are two large oceans on either side of the planet as well. They have much lower salt content than Earth's oceans do. The planet is made of lighter elements than Earth is, resulting in slightly stronger gravity.

The planet was once lush with many thick forests that could support the massive organisms. The organisms grew too big for the planet to support them and it became how it is described in the quote above.

I have quickly created a reference image using an edited image of a tortoise skeleton to answer the questions of how big it really is.

This image is poorly edited and does not represent proper anatomical proportions. Namely, the legs, which should be much thicker and stockier. As well as the head and neck vertebrae. It should also be noted that the shell is made of bone rather than keratin like Earthean tortoises.

  • $\begingroup$ Does the planet have anything similar with Earth's saprotrophic bacteria and fungi? In other words, do the bones rot or don't they? $\endgroup$
    – AlexP
    May 1, 2019 at 16:37
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    $\begingroup$ Potentially this is one of the more legitimate questions asked here, but would you care to offer more relevant details? How massive? Are we talking elephant or the moon? I smell a bit of star wars syndrome: The climate of the planet matters very little. How is it locally where the beast actually died? How long do you want it to last? Did you do some research on how long bones usually last in the desired climate? Perhaps this question can be answered by a simple google query, e.g. "how long do bones last in a forrest" gives me 300 years instantly as a starting point $\endgroup$
    – Raditz_35
    May 1, 2019 at 16:38
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    $\begingroup$ Okay so "massive organisms" is so vague it's not funny, technically any organism that weighs anything is "massive" as the word can simply mean "having mass", you need to clarify greatly before we can supply a decent answer. $\endgroup$
    – Ash
    May 1, 2019 at 16:56
  • $\begingroup$ Yes, the creature' own shell is made of bone instead of keratin. This gave its ancestors and offspring better protection against predation. The predators on this world were pretty powerful. $\endgroup$ May 1, 2019 at 17:23
  • $\begingroup$ Could you edit your question to reflect this new piece of information? Fortunatley that edit doesn't result in invalidating any current answers. Just a suggestion, but since your question seems to reflect a number of your previous questions (as you've quoted one here), you could, if you wished, create links of all the previous questions in your next one - just as a reference list if you chose to. $\endgroup$ May 1, 2019 at 18:57

2 Answers 2


Plain old bone decays quite rapidly in the cycles of wet/dry and cool/hot in temperate zones, even more so in humid rain forests in a matter of decades or less.

In deserts biological material lasts a lot longer because of lack of water (aka mummification, aka forever). However, frequent dust storms will act as sand blasting and wear away at said bones.




So, I think we're at a conflict here. On one had the bones are in a dry place and on the other it's violent and they're harboring an environment that would accelerate their own decay.

EDIT: There's also the matter of animals that eat bone or go through bone to eat marrow to consider.

  • $\begingroup$ Honestly I don't think the current question can be answered but you've made some salient points here. $\endgroup$
    – Ash
    May 1, 2019 at 17:01

I would estimate, based on mass that they would last longer than the average, which in the regions of the world on Earth that are a close fit to what you are describing is around 50 years. So, perhaps, around 70-100 years or so?

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    $\begingroup$ Could you explain how you arrived at that estimate? I mean anyone can take a guess and so can the OP. It would be helpful to give a good argument why and why not longer $\endgroup$
    – Raditz_35
    May 1, 2019 at 16:33
  • $\begingroup$ @ShimmeringCosmos I think my estimation should work for you. Scrub-lands are characterized as warm temperate, with mild, wet winters and long, dry summers. Similar to what you might find in Arizona and bones, left exposed to the elements, in Arizona tend to last around 50 years or so. $\endgroup$
    – Rob
    May 1, 2019 at 17:31

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