I was in Costa Rica for a month in 1987. My brother was in the Peace corps down there and I went and visited. I spent a lot of time with various branches of the family that had adopted him down there. One of the oldest sons (Roderico) had gotten married and moved to the coast (about 20 miles from home). On the coast, they eat a lot of fish whereas other areas live mostly on rice and beans. Roderico 5’ 5" – Roderico’s wife 5’ 0" – Roderico’s son 6’5" No one else in the family was taller than 5’7". This could be a mutation or genes that just hadn’t shown up for several generations, but I believe it’s a nutrition issue.
Spring Ice: 2 parts gin, 1 part Cointreau, 1 part Midori, 2 parts fresh squeezed lime, 7-up to fill - Garnish: Orange slice in bottom of glass.
Although there are always exceptions, taller people seem more generally successful in our (American) society, so it may be as simple as breeding for height. We’re actually able to do this as a result of adequate nutrition and healthcare, but I’d guess it’s the mate-choosing itself that’s responsible. This could possibly be verified (by someone less lazy than I) by checking stature increases over time in countries where health has improved but mate selection is dependent on other things (such as family or caste).
Re: Japanese height increases post-WWII. It seems that an end to Imperial isolationism and exposure to Western culture via mass media could’ve reversed a centuries-old cultural bias toward diminutive women and created an enhanced bias toward taller men. See above.
Also, I’ve heard that some southeast Asian cultures who use human excrement as fertilizer have shorter-than-average stature as a result of heavy metal toxicity.
Re: Native Americans vs. Europeans and disease. Even if Native Americans were not immune to European diseases, you could expect them to be less affected by some of them due to lower urbanization. They knew not to drink downstream of the village.
A quick note on armor: armor is taller with someone actually in it, so low estimates of medieval European heights based on displayed armor size have, IIRC, been discredited.
A quick note on artificial light: pineal body reactions to increased photoperiods can regulate body process rhythms, but somene recently found that there’s a cellular-level rhythm of about 24 hours that remains unchanged. Whether artificially-long days could results in increased growth is therefore uncertain. Please please please don’t ask me to find those cites.
I lead a boring life of relative unimportance. Really.
People are taller today, as compared to colonial times. Just take a stroll down to a colonial-era cemetary-you will see that the tombs are very small. I once worked for a restaurant that was in a colonial era house-out back they had a museum in the carriage house, with an old hearse-the hearse was so small-it probably could not accomodate a modern coffin. George washington was 6’1"-he was considered a giant in his day
I’m willing to bet most of those “famous names” were upper-class males. Things were a good deal more dismal for those susceptible to malnutrition or childbirth.
I’m pretty convinced that better nutrition in modern times is the cause, and that artificial lighting (or lightening, artificial or not ) has nothing to do with it.
Jois and ellis have the right idea here, I think, but I have no source immediately on hand either.
As far as woodwoodrules’ myth notion; I don’t think it’s a myth. After all, we see the same trend in modernizing coutries or in asian immigrants as their diet improves. I’m sure there were some 196 cm (OK, 6’5", that was just my little blow for the metric system ) guys around as far back as we can figure out… there are always some freaks, but we’re talking about the average here. And the armor suits of fighting men are unlikely to represent an unbiased sample of the population. Even in modern times, militaries have height requirements or restrictions.
Re: life expectancy. Sure life expectancies were in the 20s and 30s including deaths at birth for millenia, but we can really stretch 'em out now. Even without infant mortality, life expectancy in a primitive society is nowhere near that enjoyed the wealthy and insured. I also agree with bibliophage that life-threatening or shortening diseases have been around for a loooong time.
I wonder if we actually are breeding for height… it’s certainly possible, but mate choice is wrapped up in so many other factors that I’m just not sure. I’ll try to look it up…
I want to thank everyone for responding to my OP. Particularly mangeorge for the humor.
Thanks, as well to InutilisVisEst, for the reply on my artificial light question. I don’t understand it, but at least I know there is something to it.
As for the hijack, maybe this quote will clear things up.
It is from Jared Diamond’s Pulitzer-winning Guns, Germs, and Steel.
*Of equal importance in wars of conquest were the germs that evolved in human societies with domestic animals. Infectious diseases like smallpox, measles,and flu arose as specialized germs of humans, derived by mutations of very similar ancestral germs that had infected animals.
The humans who domesticated animals were the first to fall victim to the newly evolved germs, but those humans then evolved substantial resistance to the new diseases. When such partly immune people came into contact with others who had no previous exposure to the germs, epidemics resulted in which up to 99% of the previously unexposed population was killed.
Germs thus acquired ultimately from domestic animals played decisive roles in the European conquests of Native Americans, Australians, South Africans, and Pacific islanders.*
SO THERE!
Elsewhere in the book, Mr. Diamond relates that while population densities in the New World were often to low to sustain diseases, that didn’t stop epidemics from running like wildfires across this continent.
Just putting Mr. Diamond’s 2sense in
History, despite its wrenching pain,
cannot be unlived, and if faced
with courage, need not be lived again. -Maya Angelou
That may well explain it. However, I have some other ideas on the artificial-light question.
Vitamin D is necessary, in small doses, for proper bone calcification. But ironically, excess vitamin D (Hypervitaminosis-D, to use the technical term) is said to cause a decalcification of bone and calcification of soft tissues. (How it affects bone length as opposed to density, I don’t honestly know.) The primary source of vitamin D in human nutrition is through the irradiation of skin oils by ultraviolet sunlight. (Ultraviolet radiation from artificial lighting is very small, except in grow-lights). Primitive people who work outdoors all day and who bathe rarely may be getting too much vitamin D. Modern people who are rarely outside and who wash away their skin oils in daily showers may be getting much less. Additionally, those with high fish consumption (like the Japanese) are getting an extra dose of vitamin D, since fish is one of the few foods that is rich in vitamin D.
The above is only a hypothesis, and a hypothesis that my personal history would tend to discredit. When I was 15 or 16 years old I habitually drank 3 or 4 quarts of vitamin-D-fortified milk every day. I stand 6-foot-three, a good 3 inches taller than anyone else in my family. Then again, I rarely ventured outside back then, so maybe the two effects cancelled out.
I’m not sure I buy the idea that there is a limit on how tall we as a species can become. I think there is a limit on how much influence nutrition can have on the process. I think we are levelling off because nutrition can only increase our heights by so much.
However, I still think we can evolve to greater and greater heights. It will just be a slower process than the rapid increase we’ve seen due to nutrition.
If, in each generation, tall people are even slightly more successful in passing on their genes, then the species should continue to grow over time.
If this is not true, how did we ever get dinosaurs? They gradually increased in size from their smaller ancestors. The same is true for whales and the now-largely-extinct megafauna of the last ice age.
Come to think of it, we may be the smallest dominant species on the planet since the trilobites. But that is subject to change. Stay tuned for a few more eons. We may yet become “thunder mammals”.
Well, heck. My kids are both full-blooded Koreans. They grew up here, in my humble little hovel, eating typical American fare, instead of rice and fish and veggies 3 times a day ( I’ve BEEN to South Korea twice, and know of whence I speak here…).
Does this mean my kids will be SHORTER because their diet here may be a bit lower in protein than it would have been in South Korea???
Cartooniverse
If you want to kiss the sky, you’d better learn how to kneel.
A human can absorb only so much protein at once. There is plenty of protein in the average American diet – more than they can use (unless they’re big time athletes or bodybuilders).
So, they’re not going to be shorter due to lack of protein.
What’s more important nutritionally are vitamins and minerals. The varied American diet not only gives us enough of these nutrients, but some of the foods are fortified so that we get more than we need. The exception is for those junk food junkies who only eat a severely limited variety of food.
So, it’s the calcium, iodine, iron, and vitamins which we get which are causing us to reach maximum personal height potential.
Spoke said (in part): “I’m not sure I buy the idea that there is a limit on how tall we as a species can become. I think there is a limit on how much influence nutrition can have on the process. I think we are levelling off because nutrition can only increase our heights by so much.”
I think the last sentence is exactly right and what I’ve been reading has meant. But I’ve the impression that our current height is the upper limits of our genes for height.
Since we do less and less physical work we should become smaller boned and “more gracile” (what a great word). [BTW:I don’t know how anybody thinks our species can evolve just because we are such a large population. And such a perverse one, too. For example if sexual selection made only brown eyes attractive some of us would track down every blue eyed person marry one and find spouses for the rest from sheer cussedness. I think our sheer numbers would foil the natural tendency towards more compact bodies in the cold and taller thinner bodies in the heat.]
Spoke said: “If, in each generation, tall people are even slightly more successful in passing on their genes, then the species should continue to grow over time.”
Yep.
Spoke said: “If this is not true, how did we ever get dinosaurs? They gradually increased in size from their smaller ancestors. The same is true for whales and the now largely-extinct megafauna of the last ice age.”
Aren’t large dino and whales and megafauna are all by products of time, plenty of food, small initial populations?
While we have (maybe) time, and could grow plenty of food, we have a population so large that I have a hard time visualizing changes.
Not necessarily. If there is sexual selection for taller and stronger, it doesn’t really matter whether we actually need that strength in everyday life. Does a peacock need that big plumage?
The whole point is that there wouldn’t BE a “selection for taller and stronger” if there weren’t some evolutionary advantage to it. Recent studies have seemed to indicate that a choice of mate is based on factors that point to genetic success – including height. As for the peacock, he does indeed need that plumage, since that’s the way that his species has evolved in terms of mating. Without it, he doesn’t pass his genes along.
The average height for an adult American man is somewhere between 5’9 and 5’10". I’ve seen credible reports of both figures. The average height of an adult American woman is somewhere between 5’3 1/2" and 5’4 1/2". I’ve never seen any figures claiming that the average male height is 5’11". Sometimes people guess average heights as high as 6’ or 6’1" because they’re judging from people in public positions: TV, movies, politics, etc. Those people tend to be taller than average.
George Washington was not considered a giant at 6’1". He was tall, but not off the charts. He wasn’t even the tallest President.
) has nothing to do with it.