On another thread here someone cited that the life expectancy back in the hunter-gatherer days was in the 20’s; and the life expectancy in early agriculture was as low as 19 years.
I find this hard to believe – even with primitive medicine, who was dropping dead at 19 years old?
Is this true, and if so, why? Lots of hungry lions?
I know that life-expectancies are generally an average. So. . .throw in some high rates of infant/child mortality, and the average person, at birth, lives an average of 19 years. But for someone who survives to say, fifteen. . .they’re likely to live a lot longer. It’s getting there that’s the hard part.
I think 19-20 is a bit of an exaggeration. Still, diseases that we barely miss work for now could be deadly before the advent of modern medicine and immunization.
Moreover, hunters would have been injured quite often while hunting, particularly prior to the invention of the bow and arrow; a large open wound was almost certain to infect, and you would probably have had a 50/50 chance of surviving.
ETA: What AotL said, too. Mean life expectancies are much less informative than median life expectancy.
This. Quoting a “life expectancy” is almost meaningless if you don’t say what age the person you’re talking about is at that time.
Some reading here:
http://www.business.ualberta.ca/rfield/LifeExpectancy.htm
http://www.freeratio.org/archive/index.php/t-176721.html
“Gurven’s analysis revealed that 40% to 50% of the members of these groups never make it to age 15. But their prospects brighten after that, he says: A 15-year-old has a 40% chance of reaching 65, and by the time they reach 70, the mortality rate is no higher than for a U.S. resident.”
Not sure what the scientific consensus is, but if you survived past childhood diseases it makes sense that you could live quite a while with a low-risk lifestyle.
I’m not sure how “primitive” primitive is supposed to be. As someone pointed out, the Biblical notion that a man lived “three score and ten” really meant that if you survived childhood diseases and then the possibility of early violent death in warfare/hunting/hard labor (i.e.-- having a big something that you’re lifting fall on you), there was a good chance of reaching 70.The things that can kill you off early in life drag down the average, and lifetimes over 50 years weren’t unheard of in pre-technological society, or else that “three score and ten” line wouldn’t have survived.
Modern medicine’s biggest contributions to extendin the lifespan were in conquering childhood disease, then fixing up people injurede in battle or accidents. We’ve been chipping away at the upper end ever since. When I was a kid, typical life expectancy for a man was still in the 70s.
Among recent !Kung hunter-gatherer populations app. 10 % of the people reached 60 years of age or over. In Mesolithic Scandinavian cemeteries roughly 40 % of the populace are between 40 and 60 years of age. There never was a long-term society where 19-year-olds (or 23-Y-Os or whatever) dropped dead as usual business.
Depending on locale et al, violence was a leading cause of death (this is a highly debated area, but early ethnographies as well as skeletal evidence point to very deadly organized violence as well as a high incidence of manslaughter over even trivial disputes among many hunter-gatherer societies, from the Eskimo to the Australian Aborigines). Drowning, snakebite, childbirth complications also common. Any sort of spread infection (from a cracked tooth, a puncture wound in the leg etc.) would lead to death with a high probability. Paleolithic and Mesolithic skeletons typically display robust health, strong and long bones, complete, caries-free (but worn) teeth etc. People often died in their prime, “all of a sudden”. Life was precarious.
In short: many ways to get quickly killed at any age (in prime health up to the incident), but lucky ones (not that rare) would live to old age. Lots and lots of dead babies skewing the averages.
So as long as you didn’t die, you might live a long time? 
So long as you didn’t die young, you might live to be pretty old 
I’ve read somewhere that human life expectancy was pretty okay during the stone age. 40-50 years. But really dipped during the bronze and iron age.
Maybe. There’s some theory that way. What the archeologists won’t tell you is that their evidence going back that far is pretty thin, so there’s a lot of speculation.
There is a difference between lifespan, and life expectancy (the OPs question). Modern medicine has increased life expectancy considerably just in the last one hundred years. OTOH, lifespan hasn’t changed much, if at all.
If they’re anything like other scientists, they’ll cheerfully tell you at the first opportunity that their evidence is pretty thin. It’s the popularizers who won’t tell you that.
Believe it or not!
What I tried to sloppily address is that when us modern folks picture death we see old or seriously ill people slowly withering away in a downward slope of deepening disability. So when someone says “Stone Age people died in their twenties”, we tend to have images of young adults on their deathbed, ridden with disease and injury, losing the battle. How weird and awful would that be!
Typical human (and animal) death in the wild is sudden. You follow a wounded deer into an enemy encounter and get arrowed yourself. You crack a molar on an acorn and are dead in two weeks from sepsis. You slip while gathering bird eggs from a cliffside and spill your brain to feed the seagull you were cradle-robbing. Get a palm-sized burn on your thigh from frolicking too close to the fire after a hefty dose of ‘rooms and… Dramatic freak accidents by modern standards, not so in the bush sans modern medicine.