What are population growth rates of races in D&D
- Thread starter huginn12
- Start date
Nobody has worked it out, because growth rate is an empirical result, not a theoretical one. You don't get growth rate merely from fertility data, for example. The net growth rate comes from biological fertility, cultural factors around child birth, and mortality rates at different ages, whether you've had wars or crop failures and all that. Growth rate is a function of history, not just biology.
And, after all that - a modest growth rate of 1% leads to doubling in under a century.
And, after all that - a modest growth rate of 1% leads to doubling in under a century.
Maxperson
Morkus from Orkus
Ask Thanos.
Eltab
Lord of the Hidden Layer
Not with mathematical rigor or precision.
In traditional lore, orcs breed quickly and soon are over-populated for their resource base so they boil outwards in waves in all directions. The resulting fighting usually cuts their population back down to a level their resources can maintain. Repeat every two or three generations.
Elves in contrast apparently have a long-term population growth rate of Zero. (Not factoring in things like Tolkien's "take ship to the West".) Especially elves that are immortal rather than long-lived. Numbers of Elf kingdoms get involved in a ruinous war then close their borders, presumably to buy time so a new (replacement?) generation of Elf warriors can be born.
Humans are presumed to have population growth rates like IRL, and things like plague, famine, crop failure, war cut into it like you would expect. Despite all that, the number of Humans in the world must be growing over time because they spread into other races' abandoned / underpopulated space. And keep doing silly stuff like move colonies full of civilians into land near Orc strongholds.
Dwarves have the "not enough females" problem or at least you almost never see one. In Forgotten Realms, the "Blessing of Moradin" was a generation of twins so there would be enough Dwarves to handle all the tasks (including wars) that Dwarf society needed to accomplish. Their population seems to be stable or gradually declining.
I can't speak to other races but many are tied to certain landscapes (mountain) or ecosystems (forests) so their populations would have a natural maximum without large-scale environmental engineering projects.
aramis erak
Legend
Medieval demographics are of limited use, due to effective healing magic.
and no edition of D&D has good data. 2E has the best, but it doesn't match 5E
We do know that elves suffer very low infant mortality (2E Complete Elves) [human was almost 50% in many places], and low birth rates. (2 year pregnancy, as well, ibid.), for probably 3 births between age 110 and 150 (the adult years before middle age), with about 2.9 surviving. so, 2.9 per 110 years birth rate per couple, or 1.45 per person, peak. Non-violent death is around 45.
If we assume the fecund period is only adult and middle age...
we get about 50/450 of the population is fecund, and they average 2.9 per couple living to adulthood, and 1/450 dies annually... 90% of fecund age reproduce... I get 4538 years minimum doubling time for elves in 2E.
Humans, with 15-40, and 6 kids, with 35% infant mortality rate, and the D&D 100 death, I get 151 years minimum doubling. (this is a 20% reduction in infant mortality, and 1 extra child, over historical, plus 2.1x median death age, but median death for medieval was lowered highly due to plagues)
Dwarves, we are told, are suffering a 4:1 ratio of M:F, so only 20% are reproductives, and even the reproductives don't get started until twice adulthood, and average similar numbers of children as humans per couple... but with low (1%) infant mortality... 1107 years doubling time minimum
Orcs, per complete book of humanoids, and historical human numbers of children and infant mortality:
Age, adult 10
age, max middle 17
Age, death 40
Births per fecund period 5
Infant mortality 0.45
rate of reproductives 0.9
Years 118 to doubling, minimum.
If we up the children to 1 per year... for 7 children per couple, it drops to 38 years...
Orcs positively explode compared to the others.
Attached is the XLSX of my numbers spreadsheet I used to work it out.
Note that warfare, plagues, and curses will drastically increase population doubling times. Dwarves, if you reduce births, or increase infant mortality to even 5%, go into a death spiral.
and no edition of D&D has good data. 2E has the best, but it doesn't match 5E
We do know that elves suffer very low infant mortality (2E Complete Elves) [human was almost 50% in many places], and low birth rates. (2 year pregnancy, as well, ibid.), for probably 3 births between age 110 and 150 (the adult years before middle age), with about 2.9 surviving. so, 2.9 per 110 years birth rate per couple, or 1.45 per person, peak. Non-violent death is around 45.
If we assume the fecund period is only adult and middle age...
we get about 50/450 of the population is fecund, and they average 2.9 per couple living to adulthood, and 1/450 dies annually... 90% of fecund age reproduce... I get 4538 years minimum doubling time for elves in 2E.
Humans, with 15-40, and 6 kids, with 35% infant mortality rate, and the D&D 100 death, I get 151 years minimum doubling. (this is a 20% reduction in infant mortality, and 1 extra child, over historical, plus 2.1x median death age, but median death for medieval was lowered highly due to plagues)
Dwarves, we are told, are suffering a 4:1 ratio of M:F, so only 20% are reproductives, and even the reproductives don't get started until twice adulthood, and average similar numbers of children as humans per couple... but with low (1%) infant mortality... 1107 years doubling time minimum
Orcs, per complete book of humanoids, and historical human numbers of children and infant mortality:
Age, adult 10
age, max middle 17
Age, death 40
Births per fecund period 5
Infant mortality 0.45
rate of reproductives 0.9
Years 118 to doubling, minimum.
If we up the children to 1 per year... for 7 children per couple, it drops to 38 years...
Orcs positively explode compared to the others.
Attached is the XLSX of my numbers spreadsheet I used to work it out.
Note that warfare, plagues, and curses will drastically increase population doubling times. Dwarves, if you reduce births, or increase infant mortality to even 5%, go into a death spiral.
+1.
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