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kassyopeia from terrae nullius Since: Nov, 2010
#26: Dec 17th 2010 at 12:50:06 AM

If one looks at the extreme ends of the spectrum, a correlation does seem likely, IMO. Elephants, whales and giant turtles are famously long-lived, and many of the small insect species are very short-lived.

Also, a correlation between gestation and growth times to adult size on the one hand and total life-span on the other seems likely.

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
kassyopeia from terrae nullius Since: Nov, 2010
#27: Dec 29th 2010 at 12:20:10 PM

Coincidentally, I got a book for christmas (called "Encyclopedia of the Unknown") which contains an essay on animal sizes, covering topics like Bergmann's, Cope's, and Foster's (so-called) rules. The problem in coming up with simple dependencies is that neither smaller nor larger is better, per se, but that it usually comes down to a finely balanced structure of advantages and disadvantages.

Anyway, these are the correlations that hold most of the time, when a species increases in size:

- longer life-span,
- less offspring in more time,
- lower food consumption, per unit of body weight and time,
- higher degree of dietary specialization.

So, my hobbits should live less long, have a shorter gestation period and a higher incidence of multiple births, eat (relatively) more and/or more often, and be more omnivorous, than humans. Scratch the last one, as we're already doing fairly well in that respect, as far as I can tell.

Also, which I'd never heard before, larger animals tend to not only have more, but also larger cells. If that applies to neurons, it'd go some way towards explaining why there's no obvious dependency of intelligence on brain size, among closely related species.

edited 29th Dec '10 12:21:14 PM by kassyopeia

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
LoniJay from Australia Since: Dec, 2009 Relationship Status: Pining for the fjords
#28: Dec 29th 2010 at 2:42:46 PM

Well, it would make sense for nerve cells to be longer; a nerve that goes from your spine to the tip of your finger is one cell. I'm not sure bigger cells would have that much effect on intelligence, though.

I'd never heard that, about bigger animal cells being bigger. Interesting.

Be not afraid...
Madrugada Since: Jan, 2001
#29: Dec 29th 2010 at 2:58:58 PM

Are you sure that Bigger = "longer lifespan in general" within the same species? because if so, dogs are basssackwards; the larger breeds almost always have shorter expected lifespans than the smaller breeds.

Flayer Since: Nov, 2010
#30: Dec 29th 2010 at 3:25:13 PM

I think that might have to do with the fact that dogs have been bred to be be larger from an originally smaller size, and the problems come with their organs and stuff not necessarily being in proportion to their larger body. I'm obviously not certain about that, though, but it seems to make sense.

Smaller animals tend to run on a faster metabolism, with a more rapid heartbeat and digestion (and hence needing more food relative to their size), and they also tend to sleep less.

But there aren't really absolutes. Shrews, for example, need to spend about 22 hours a day eating, but koalas spend about 22 hours a day sleeping. Nature and evolution don't necessarily follow the paths of perfect efficiency and engineering, in fact, just about every animal has some sort of flaws in its "design."

LoniJay from Australia Since: Dec, 2009 Relationship Status: Pining for the fjords
#31: Dec 29th 2010 at 3:51:21 PM

I think that list was intended to apply between species, not within them.

Anyway, dogs aren't a terribly good example, because humans have messed around with their genetics so much they don't know if they're coming or going.

[up] That's actually not it - I think it was small dogs that were bred from bigger ones, not the other way around. Small dogs like chihuahuas actually are shaped more like a puppy or fetus than a grown dog; it's called neoteny.

edited 29th Dec '10 3:51:56 PM by LoniJay

Be not afraid...
rodneyAnonymous Sophisticated as Hell from empty space Since: Aug, 2010
#32: Dec 29th 2010 at 10:28:16 PM

[up][up],[up] Yes, all dogs are descended from wolves (~10,000 years ago... artificial selection can do stuff quick! but is less "through-and-through" than natural selection)... smaller dogs were bred from larger dogs; if you look up neoteny, see also "paedomorphosis" (the retention of juvenile features into adulthood, which is the deliberate goal of neoteny/juvenilization).

Lots of this has been addressed already, just two more cents:

(trying to stick with mammals)

  • There are both advantages and disadvantages to physical size, irrespective of ecosystem role. (Although predator species tend to be large.)
  • AFAIK mass is not directly related to lifespan, but if we understood lifespan perfectly, there would be an immortality pill.
  • Smaller creatures tend to have faster heartbeats than larger creatures: the volume of the heart is smaller, so it has to pump faster to move blood around. This is offset by having less blood to move around.
  • Relative strength might be higher, but linear strength would not; e.g. a huge man swinging a mace into your gut would hurt a lot more than a small child doing the same. Ants may be able to lift some large multiple of their own weight, but compared to me, they are weak.
  • On climbing: yes, lower mass means less falling damage. To something really massive like an elephant, a fall of even a few feet is fatal. To something exceptionally small, like a mouse, terminal speed is so low that the creature is effectively immune to falling damage from any height. Hobbits would be somewhere between a human and a mouse (and much closer to the human).

edited 30th Dec '10 2:45:40 PM by rodneyAnonymous

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kassyopeia from terrae nullius Since: Nov, 2010
#33: Jan 5th 2011 at 5:01:13 AM

I'm not sure bigger cells would have that much effect on intelligence, though.

What I meant was that a smaller brain could be just as complex as a larger brain, if the smaller brain consists of smaller cells.

I'd never heard that, about bigger animal cells being bigger. Interesting.

Unfortunately, the essay wasn't very clear on which types of cells this applies to. It may just be those which have an individual function, like the blood cells and hair follicles and so on, and not those which form macroscopic structures, like muscles and bones. *shrug*


Are you sure that Bigger = "longer lifespan in general" within the same species? because if so, dogs are basssackwards; the larger breeds almost always have shorter expected lifespans than the smaller breeds.
I think that list was intended to apply between species, not within them.

The list (supposedly) applies to natural changes within a narrow taxon, like a single species or a family of species. So, it should work for comparing two geographically isolated populations of wolves, one of which is unusually large and the other unusually small. And it should work for comparing wolves to foxes. It won't work for comparing wolves to sharks, as their metabolism doesn't have enough common ground, I think.

Anyway, dogs aren't a terribly good example, because humans have messed around with their genetics so much they don't know if they're coming or going.

Yeah, I think that there's no reason to expect it to apply to domesticated breeds. The changes are likely as much a product of evolutionary pressure as of necessity, so breeding takes away at least that component.


On climbing: yes, lower mass means less falling damage. To something really massive like an elephant, a fall of even a few feet is fatal. To something exceptionally small, like a mouse, terminal speed is so low that the creature is effectively immune to falling damage from any height. Hobbits would be somewhere between a human and a mouse (and much closer to the human).

I wonder if there's a weight below which death by hanging is no longer possible (without using external weights, I mean). Maybe there isn't, because one can make the rope thinner as the creature gets lighter, so the exerted pressure stays the same?

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
AnthropoRex Since: Feb, 2011
#34: Feb 2nd 2011 at 9:29:07 AM

I don't think anyone's mentioned this yet, but there were Actual Hobbits. Well, Homo floresiensis. If I remember correctly, they were about half as tall as modern humans but their skulls and brains were one third the size of modern humans. They are believed to have made and used stone tools, but no other artifacts have shown up yet due to poor preservation in the tropics. Oh, and they lived on an island with giant birds and dwarf elephants (some of which have been found associated with Hobbit stone tools!).

Here is the link to the other wiki: http://en.wikipedia.org/wiki/Homo_floresiensis

kassyopeia from terrae nullius Since: Nov, 2010
#35: Oct 17th 2012 at 10:07:02 AM

For Altlings (described as hobbits in this thread of yore), the weapon of choice is the glaive, which is in almost every way a quarterstaff.

According to several contemporary sources I found, the proper dimensions for a tailor-made English quarterstaff (the Medieval "serious business" version, not the duelling version of later centuries) were these: A diameter of three fingers, that being the maximum that can be comfortably and safely gripped (easy to confirm using one's own hands), and a length equal to the wielder's "full stretch", which is to say the distance between the ground and the fingertips of an upraised hand, plus another two handbreadths "to account for the portion of its length that are covered by one's hand when in use" - I suspect that last part may be bunk, though.

Assuming Altlings are typically twice as strong, pound per pound, as humans, as discussed upthread, does this algorithm work for them anyway, or would they tend to use relatively longer weapons, employing that extra strength to increase their reach?

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
McKitten Since: Jul, 2012
#36: Oct 17th 2012 at 12:48:57 PM

The brain issue isn't quite as straightforward as just increasing neuron count and surface area unfortunately. A quite significant part of human calorie intake for example is required to keep our massive brains running, that couldn't be reduced if you want as many comparable neuron operational. A more tricky problem is that our brains generate quite a bit of waste heat, packing them denser puts them at risk of overheating.

On the other hand, purely physical abilities scale excellently for most cases. While the square cube law is mostly about surface area vs. volume, some things do not scale at all. For example hardness. A large bone is just as hard as a small bone. (not to be confused with force it can take before snapping) Generally speaking, this makes smaller things much less prone to injury due to events happening at their scale. For example, dropping a brick on your foot will result in quite a bit of bruising, if a rhesus monkey were to due the same with a brick that's to scale, it probably wouldn't even hurt.

But that's got downsides as well, mostly when a smaller species has to work materials during a technological phase where they're still relying on muscle power. The amount of strength you need to swing a smith's hammer is determined by how hard the piece metal is you're working, not how large. Similarly if you're using bone or wood or flint. And furnaces for example can't be scaled down at all.

The quarterstaff wouldn't work at all i suspect. With weapons like that (also clubs, maces etc.) inertia and weight are very important, and having lighter versions doesn't work too well.

edited 17th Oct '12 1:05:06 PM by McKitten

kassyopeia from terrae nullius Since: Nov, 2010
#37: Oct 17th 2012 at 1:32:18 PM

I do not believe that the brain issue exists. If we can breed a wolf into a poodle without making it significantly stupider in the process (certainly after accounting for the intelligence loss due to domestication as such, at any rate), the human brain would have to be very different, on a qualitative level, for the much less significant reduction I'm proposing to be implausible. And even if the issue is indeed a real one, I'd at this point be perfectly happy to ignore it, considering that the size reduction is one of the cornerstones of my worldbuilding. What I mean to say by that is that you needn't waste energy and time trying to convince me, because at best you'll get me to invoke creative licence in this matter.

Your points regarding hardness and other "unscalables" is very interesting, though. Altlings have not developed any kind of metal-working other than perhaps turning precious metal nuggets they happen to find into jewelry. The hardest material they work, that I can think of at the moment, would be stone. Meaning flint-knapping, specifically. That takes controlled rather than particularly hard blows, but they'd still need to recruit a bigger portion of their total strength than a human would. On the other hand, simply being smaller should give them more control in various ways (shorter levers, nimbler fingers, et cetera): Do you think the end result would be that they'd be better or that they'd be worse at it, overall?

Regarding the quarterstaff, its intended effect when striking is to disable rather than kill, which, since the human-sized version was quite easily capable of the latter, means that reduced force is actually a good thing. When thrusting, it should be able to break bone, but that comes down as much to concentrating the force in a small area and to the strength of the particular bone at the other end, as to the total force of impact, it seems to me. But I'll take your answer to mean that a proportionately heftier staff would be more plausible, yes?

edited 17th Oct '12 1:40:41 PM by kassyopeia

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
McKitten Since: Jul, 2012
#38: Oct 17th 2012 at 2:49:37 PM

Well, i don't know wolves, but i do know poodles, and have a hard time believes wolves (or, say, slime mould) could be stupider. evil grin

I'd think that having to swing harder, or use more strength to wield a relatively heavier tool would greatly diminish accuracy, but in the end, it's probably less likely that the species as a whole will be worse at it than humans, than that it simply means less of them have the potential to become good at it. It's like that with most things where individual skill has a very wide range.

How about making the staffs thicker just at the ends? If the last 10cm or so are heavy enough, that would provide almost all of the momentum a overall thicker staff has when swung. Weapons intended to kill would probably need to be made of stone (or at least the ends), that should have them fall somewhere between a human-sized club made of wood and a human-sized club made of stone, so perfectly capable of breaking bones and killing.

kassyopeia from terrae nullius Since: Nov, 2010
#39: Oct 17th 2012 at 3:46:32 PM

Actually, I quite like the spin this puts on flintknapping as a trade. They'd be the blacksmith equivalents in several ways - a relatively rare skill that it takes a long time to gain mastery in, and one that requires (and produces) a lot of brawn in its adepts. Oh, and they could wear something like those leather aprons too, to protect themselves from the sharp rock splinters. Nice.

Now that you put it that way, maybe the simplest solution to the quarterstaff issue would be to simply posit that the wood those are made from is considerably heavier than normal wood? It already comes from a tree that is peculiar in a lot of ways, and while I had not considered that idea before, at first glance it doesn't seem to have any negative side effects on anything else. Earth's "ironwood" has densities of up to 1,500 kg/m^3 already, according to wikipedia, which is like bone. Typical stone has densities of or above 2,500.

If I split the difference and give my "inglewood" a density of 2,000 (which would be like that of brick and three times as high as that of ash and oak, which were usually used here), the Altling quarterstaff following the algorithm I found would be proportionately heavier to wield than the human one: One eighth the volume, three eighth the mass, compared to one quarter the absolute strength of the person doing the wielding. How does that sound?

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
McKitten Since: Jul, 2012
#40: Oct 18th 2012 at 1:21:44 AM

Sounds pretty good, should make a very usable weapon. Maybe also extra-light wood (like bamboo) for practice combat or full-contact competitions to make them less risky?

edited 18th Oct '12 1:22:05 AM by McKitten

kassyopeia from terrae nullius Since: Nov, 2010
#41: Oct 18th 2012 at 3:05:13 AM

Yes, those manuals the sizing recipe is from mentioned bamboo for that purpose as well.

And I've already incorporated pretty-much-bamboo ("barrelwood") into my world, for the purpose the name very much suggests, so that's a no-brainer.

Maybe they should have an even heavier version as well, for solitary exercises that help build muscle and stamina and gain better control? The only way to make it even heavier would be just what you suggested previously, though, put weights at both ends, which might make it a slightly different wielding experience than the ordinary staff. Hmmm.

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
McKitten Since: Jul, 2012
#42: Oct 18th 2012 at 3:35:41 AM

Well, should make for good strength training, because for fighting you really want to train strength, speed & precision, not just peak strength as in weightlifting, but a staff with significantly heavier ends would probably handle very differently from one with uniform density, probably more like a mace or heavy spear with counterweight. No idea how well that would work out, but i suspect the handling would be different enough to make the switch awkward. Then again, most warriors in history trained with more than one weapon anyway.

Kesteven Since: Jan, 2001
#43: Oct 18th 2012 at 4:01:15 AM

With regard to the brain size issue, perhaps Encephalization quotient is relevant? The implicated connection to intelligence is that there are many factors other than mass determining brain effectiveness, so it's not total brain size that's important but brain size relative to the 'standard' brain for that body size, i.e. how much 'excess' brain there is.

I haven't worked out how that applies to hobbits but it shouldn't take that much maths to work out how big their heads would have to be to achieve an EQ on par with humans. You know, if you're into that.

edited 18th Oct '12 4:05:19 AM by Kesteven

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kassyopeia from terrae nullius Since: Nov, 2010
#44: Oct 18th 2012 at 7:09:06 AM

[up] Well, can't hurt to try! If I understand the article properly, it implies that the brains of differently sized mammals with similar levels of intelligence seem to scale approximately as (brain mass)^3 / (body mass)^2 ~ constant, which in turn implies that relative brain mass (the ratio of brain mass to body mass) should scale as the inverse cube of body mass.

Altlings weigh about one fifth of a human, so their relative brain mass should be about five-thirds of that of a human. In other words, they need 70% more brain than isometric scaling would provide. On the other hand, simplistic allometric scaling gives them a neck 100% stronger without adding extra muscle. Meaning that we're more than fine anatomically, but that I should think of them as being slightly differently proportioned in regards to balance.

The best comparison is probably a subadult human. Macroscopic brain growth is pretty much complete a few years after birth; thus, a human would reach a similar ratio at about three-fifths of their adult bodyweight. Which corresponds to, what, pre-teens? Anybody remember if balance issues were noticably different then than they are for a fully grown body?

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
McKitten Since: Jul, 2012
#45: Oct 18th 2012 at 9:14:45 AM

I doubt it would get anywhere near sizes that make balance an actual issue. Although other things should be noticeable, for example the heating problem i mentioned and the calorie intake. I.e. they'd need a disproportionately large calorie intake (correct foods as well, it has been theorized that increased meat consumption of our ancestors was what allowed them to develop intelligence in the first place) and would be quite vulnerable to heatstroke (freezing as well, though putting on a hat is easier than putting on an AC).

kassyopeia from terrae nullius Since: Nov, 2010
#46: Oct 18th 2012 at 10:40:32 AM

I didn't so much mean that it would be a problem, as that it would simply be different and thus something to be potentially having to be taken into account when writing "action scenes", as I think I originally put it. To give an example, a human would probably use a ladder to get off the roof of their house, even if it's not multistoried. It wouldn't be a dangerous jump, but the slight chance of twisting one's ankle or some such would already outweigh the time that could be saved by jumping. For an Altling, the house being only half as high and their body being both lighter and relatively sturdier, that estimation of risk versus gain may well come out the other way around.

Similarly, having a not hugely but noticably bigger head may change the way their bodies behave and, thus, the ways in which they employ them, in significant ways, on occasion. Or it may not, that's why I raised the analogous case of human children.

The heating problem disappears completely, with the above adjustment. We now have somewhat fewer somewhat smaller brain-cells in an absolutely somewhat smaller and thus relatively somewhat larger-surfaced head, so the extra heat due to the former is, per square-cube, approximately compensated for by the latter.

Caloric intake, I've already taken account. Their usual schedule has them eating a "morsel", which is like a sandwich, every hour and a half, and a major meal every nine hours. The total meat supply per person is a hundred grammes per one of their days, which is equivalent to half a pound per one of our days for us. The total other supply in listed here.

Higher vulnerability to cold and heat I've also taken into account. One of the plot-relevant parts of the setting is a supposedly un-crossable mountain chain, which is made more plausible by that circumstance.

Please do keep the potentially problematic issues coming, if you can think of more - there are bound to be some that I've not yet considered!

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
HyperAlbion Taking Back our 40 acres Since: Sep, 2012
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#47: Oct 18th 2012 at 2:04:56 PM

Well your average Hobbit in the prime of his youth at 30 would be around 3 foot six and weigh 55 pounds. A pretty healthy BMI actually.

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AnotherDuck No, the other one. from Stockholm Since: Jul, 2012 Relationship Status: Mu
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#48: Oct 18th 2012 at 2:37:35 PM

I don't think BMI scales very well that way. Or scales well at all. Or works well at all.

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kassyopeia from terrae nullius Since: Nov, 2010
#49: Oct 18th 2012 at 2:41:17 PM

That's the height I've been working with, yes, but almost twice the weight. I figured about a fifth of a human's, which is an average of 30 pounds or so. On the BMI scale, that would indeed be somewhere in the "severely underweight" range, or whatever it's called, but it's obvious from first principles that that scale is rather specific to human anatomy in the typical human range of sizes, and can't be readily generalized. How did you arrive at the figure of 55 pounds, by the way? smile

ETA: "Prime of youth", for Altlings, is at about 15 Earth-years or 60 in-universe "years": Accelerated aging, tighter planetary orbit.

edited 18th Oct '12 2:47:12 PM by kassyopeia

Soon the Cold One took flight, yielded Goddess and field to the victor: The Lord of the Light.
HyperAlbion Taking Back our 40 acres Since: Sep, 2012
Taking Back our 40 acres
#50: Oct 18th 2012 at 2:54:44 PM

If this is just some OC race of yours why are you asking us about Hobbits?

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