Medieval Demographics Made Easy: For Non-Humans?

[Xeviat]

Fungal farming could work. Like you pointed out, you need something from the surface to feed the fungi, unless you want to get real strange and have chemosynthesizing bacteria as the base of a food chain (and I doubt that would get robust enough to support a city). I do want to avoid magic being the only way a city could work. For my own setting, though, I will definitely have exotic livestock.

Ghostman, if I gave you general numbers for lifespans, what type of input could you give? Or were there some generalities you could say? My own elves are going to be nearly a century till sexual maturity, and from that they have a child every ten years; on the surface, this looks like it would create a race that would have a very difficult time bouncing back from wars and disease; would probably need much smaller numbers.

[Ghostman]

Is the one child per ten years an average or is it the upper limit? In any case, a hundred years is a pretty long time that probably could cause serious problems for the race.

Perhaps I'll just cook up a quick example with some arbitrary numbers...

Generic race:
* Assume 50% of children die before reaching sexual maturity.
* Assume it takes 30 years to reach.
* Assume that those who did, will on average live up to 90 years old.
* Assume that there is no maximum age for fertility, so each couple has on average 60 years of breeding to contribute to population growth.
* Assume that the average couple will have 6 children through their lives.
* Of the 6 children per couple, only 6 x 50% = 3 will live long enough to reach sexual maturity. These will not contribute to permanent population growth.
* Assume a total adult population of 100,000. For sake of simplicity, we'll assume that there are no loners; that's 50,000 breeding couples.
* Those couples will, over a timespan of 60 years, produce 6 x 50,000 = 300,000 children. Only 150,000 of these will live long enough to reach sexual maturity.
* By the end of the 60-year cycle, the original 100,000 breeders will be dead.
* This gives us a net effect of 150,000 - 100,000 = 50,000 to the adult population. That is the growth over 60 years.
* The increase per one year will be approximately 50,000/60 = 833. Divide that by the starting population of 100,000 and multiply by 100%, you get +0.833% growth per year.

Of course, this is an extremely simplified model. It doesn't take into account the children being born and the grown-ups dying at different times within the 60-year cycle. The population growth is also not actually linear; it should prolly start lower then +0.833% and grow bigger each year. But it's much easier to calculate things in this manner, and the result might still be a fair approximation. Naturally you can get more accurate results by using a better (probably more complicated) model.

In my simple model, a loss of a portion of the adult population (eg. due to war) within the 60 year cycle could be represented by lowering the average post-maturity life span, and lowering the average number of children in the same proportion. (ALL the adults from the beginning of the cycle will be dead at it's end regardless; but those who died prematurely due to the war had less time to breed, hence less children were born to be accounted for at the end of the cycle.)

[Xeviat]

Interesting. I'm dealing with my wedding stuff, but as soon as I get back I will be hitting the books hard on this. I also need to find a web designer to help me with my site; my friend can't do what I need.