There are a number of humanoid creatures in fantasy that we more or less take for granted. Humans are almost a necessity for us to be able to relate to the story and they interact with dwarves, elves, goblins, orcs, and a plethora of other exotic humanoids. One thing often lacking in fantasy stories is how these creatures grow from infancy to adulthood.

Elves suffer the most from this lack, but it exists for most of them. Many humanoid species encountered in fantasy tales live far longer than humans. Elves are often described as living for 300, 700, 10,000 years, or even indefinitely.

Immortal elves are clearly magical, but it also raises an interesting question: How long does it take a fantasy humanoid to reach adulthood? Should this be measured as a certain fraction of their life expectancy, or is there some physical, mundane explanation for why a species achieves a (relatively) early adulthood and ceases to age until late in life?

  • $\begingroup$ Are you asking about the factors which would make a species' length of childhood longer or shorter. $\endgroup$
    – user243
    Commented Jun 10, 2015 at 1:44
  • $\begingroup$ @JonofAllTrades At it's simplest, yes, I suppose I am. $\endgroup$
    – Frostfyre
    Commented Jun 10, 2015 at 1:45
  • $\begingroup$ This begs the question: how do you define your elves? There isn't a hard and fast answer to 'when do elves mature', since different sources and different authors have created elves that are at various rates. Tolkein's elves, for example, mature between 50 and 100 years of age: lotr.wikia.com/wiki/Elf_children. In dungeons and dragons, on the other hands, elves become adults around the age of 20 or 25. Neither of these, or any answer, is really 'wrong' or 'right', unless you have more information about the elves in question. $\endgroup$
    – ckersch
    Commented Jun 12, 2015 at 21:08
  • $\begingroup$ @ckersch I was intending more of a general approach to the question, not specifically for elves. I merely used elves as one example. $\endgroup$
    – Frostfyre
    Commented Jun 12, 2015 at 21:16
  • 1
    $\begingroup$ I'd contend the same for any fantasy race: their childhood and growth will depend on the context in which they exist. PipperChip's answer, for example, holds true under the assumption that dwarves and elves are hominids with a common ancestor to humans, but if dwarves were crafted from rocks by the dwarf god, the underlying assumptions are no longer valid. Especially for immortal races, which don't make sense evolutionarily, an answer to the question of 'why do they exist and what are they,' will be critical to describing their grown. $\endgroup$
    – ckersch
    Commented Jun 12, 2015 at 22:07

3 Answers 3


I'm a fan of mundane reasons, and of calling elves and dwarves "fantasy species" or "fantasy hominids" instead of "races." Here are several mundane reasons for similar growth and maturation rates across your fantasy hominids:

Historic Hominid Growth Rates

Very clever researchers have examined the growth rates of ancient hominids. They've found that there are growth rates for hominids are all over the place! Some of them grew just as fast as modern humans, whereas others grew faster or slower. Another paper claims no correlation between body size and growth rates. The growth rates of certain variables do seem to be shared between certain species, but nothing so simple as "a creature can expect 30% of their life to be spent as a youngster."

It seems that Bonobos, Orangutans, and Chimpanzees are giving birth for the first time at around 14 years old, at have a maximum age around 55. (Compared to the human hunter-gatherers, who can give birth at around 19, and live to be 85.) Given the number of related species who have their first children around the same time, the second paper mentioned concludes that the ancestral hominid likely reached sexual maturity around age 13 to 15. If your fantasy world assumes some sort of evolutionary connection between humans and other fantasy races, this baseline of sexual maturity around 14 should be kept. Obviously, this extended pubescent period found in humans could be carried over to these fantasy hominids.

Factors of Growth Rates

There do seem to be some common factors which help determine growth rates:

  • Food: the type of food and how much was available seems to determine how quickly a species can grow. The more calories you get from your food, the more you can put into growing, surviving, and rearing offspring.
  • Total Body Mass: The more massive a creature is, it seems it takes longer to get that massive, given a similar diet compared to another creature. It also indicates that the babies of more massive specimen are more healthy, simply because the larger animal can expend more resources on their child.

The Grandmother and Patriarch Hypothesis (And Another)

So why would a species want to mature quickly, and then go ahead and have a long time spent as an adult? Kin Assistance is an answer here. The idea is that longer lived, possibly infertile, adults can provide assistance to those younger than them. This assistance can guarantee their offsprings' survival, making it a good evolutionary strategy.

Alternatively, older individuals can have some better advantage in the make-babies race of evolution, so it benefits to be a physiologically older individual than not. This means that those who grow up fast can get to make more babies, resulting in babies which grow up fast, so they can make more babies. You see this in lobsters, but this idea is part of the core of the Patriarch Hypothesis, so you can see this in hominids.

Another answer can be found in the idea that babies are a resources drain. If two species are in competition, and the main difference between them is maturation rate, the species who matures more quickly can defend and out compete the other. The slower-maturing species would be spending resources on their babies while the other is doing other things, possibly with more capable adults. This is not quite the same as the Patriarch or Grandmother Hypothesis, but it is a good reason why dwarves and elves should grow up about as fast as humans. This is especially true when fantasy hominids compete for resources.

  • $\begingroup$ Is there a functional difference between hominid and humanoid? Regardless, +1. Excellent response. $\endgroup$
    – Frostfyre
    Commented Jun 10, 2015 at 3:58
  • $\begingroup$ hominid = great apes and it's a real thing, it assumes that the evolutionary origin is the same. Humanoids are instead the product of convergent evolution: unrelated animals become very similar because of the environment. This is why biped intelligent aliens are humanoids: they are completely unrelated to humans, maybe even life molecules were created independently, but finding themselves in a savannah-like environment and needing to hunt led them to develop the same characteristics as humans. $\endgroup$
    – Formagella
    Commented Jun 10, 2015 at 14:09

If we define adulthood as the period when a creature reaches sexual maturity, then adulthood in humanoid fantasy creatures can be estimated upon at least two different factors.

  1. Humans have a prolonged childhood due to the size, complexity and and energy consumption of the developing brain. Because the brain takes so much energy, less of it is left for the rest of the body. A more intelligent species, or species with magical abilities on top of regular human like cognitive processes will have a longer childhood as their brains use up more resources to develop.

  2. Which means their bodies- at least that of the females- will take a longer time to develop, and to reach sexual maturity, because she has to be large enough to carry a baby to term.

So... I assume elves would spend the most time in childhood, and certain species of Orc, the least.

Edit: Also, females of most species tend to mature a few years ahead of the males. This could be due to infanticide rates -males of the same species killing off babies and then taking the mother as their mate- so the sexually mature male also needs to be large enough to fend off his mate and child.

So... Male maturation rates would depend on other factors -are the women equally warlike as the men? Do non blood related males form strong friendships?


In Tolkein's mythos, the Elves were created whole and awakened during the Age of the Stars, so issues like birth and ageing seem to have been bypassed. (Tolkein grew his mythos over many decades, so there are various inconsistencies to the stories). Since Orcs are Elves who were twisted and mutilated by Melkor, there should also be a large but finite number of Orcs in Arda as well.

While this does not directly answer your question, it shows there is a range of possibilities that can be explored within a fantasy world.

  • $\begingroup$ Tolkien's elves do reproduce in every version of his mythos that I've heard of. Only the first elves were created as adults (as were the first humans and the first dwarves). Though it's true that they don't have a lot of kids; see scifi.stackexchange.com/questions/91588/… $\endgroup$
    – MJ713
    Commented Apr 27, 2023 at 17:25

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