Watching that battle, my mind went immediately to Dodge Ball. Play that simulates perhaps our most natural type of group fighting.
Various neighborhood kids would take the dirt fort and try to hold it against the other neighborhood kids who came and ... everyone threw "dirt clods" at each other. A few rules like "no rocks" were understood.
Otherwise the battle resumed every day the workers weren't working on the dirt pile... it was glorious. Win or lose you returned home each day dirty as could be, and very happy you did your duty that day alongside your friends from the neighborhood.
That is a long way of saying that sometimes I see some strange "tribal" stuff that seems weird to me, and actually no I kinda get it.
Fighting always works better when only your side is doing it.
A History of Warfare by John Keegan is a good introduction to military anthrolopogy, with an extensive bibliography.
(Attacking them in their beds, pah, don't you think maybe the neighboring tribe thought about that and had someone on watch?)
I have read stories about this happening in the current day Amazon.
In nonhuman animals, even in fierce disputes over territory and mating, killing is rare, because it's quite costly: you eliminate completely a healthy individual, and usually would run the risk of serious injury yourself, making both dying likely. Usually they e.g. resolve mating with displays of beauty/fitness, and territory with displays of force (chimpanzees for example have lots of display of force rituals, specially around selecting leadership, I believe) and sometimes non-lethal conflict (some species evolve apparatus just for this kind of conflict, e.g. antlers, so they can engage in conflict with low chance of injury).
Since we're referring to human cultures, something distinct we have is memory and communication -- information can get out on reputation, behavior, etc. of a group. I think if a group just goes out and murders another in their sleep (which TBF is not so easy), then I imagine for example word would also go out of their actions and may get into trouble with other groups, I'm sure spiritual traditions would also have a say about it, in favor of some sort of "spiritual revenge". But I suppose it's difficult to generalize.
I do think it's interesting to consider some forms of morality, or just metaphysical and logical understanding around ethics, as a kind of technology that enables people to live longer and enable more secure conditions, including preventing large scale conflict that can bring destruction on an industrial scale to entire societies (although misguided moral arguments ironically are also misused sometimes to enact destruction). Although I guess morality alone is not enough (because not everyone seems to internalize it well), and other mechanisms are also helpful to achieve more social stability.
(Also of note is that there can be such thing as too much stability -- for example, for some new more interesting and maybe more worthwhile forms of culture to emerge, old ones have to be replaced, so stability should be balanced with cautious openness to new ideas, technologies, methods, peoples (ethnicity), cultures, ..., and worldviews -- of course, as long as change is in the direction of improving our lives collectively. For example in some cases religious fundamentalism advocates for an absolutist cultural stagnation; we just shouldn't need one group to murder another to spread about new things)
In general, though, pre-agricultural societies tend to have very high mortality rates from armed conflict with outgroups. In PNG in particular, as I recall, it gets to the point where >20% of all males die from enemy action. Similarly, pre-agricultural societies rarely take prisoners, and often target what we would consider non-combatants (i.e. there's no separation between "enemy warrior" and "enemy civilian", even in principle).
And this makes a lot of sense when you consider what motivates this warfare. Pre-agricultural societies are bounded by the output of the wildland that they forage on, and a single human requires a lot of land to live off in this manner. This is why those bands tend to be small - very few biomes can sustain a foraging band of even few hundred. But conversely it means that any other band of humans foraging off the same land is literally starving you out. It doesn't matter if they are otherwise hostile or not, and there's no potential compromise to be achieved even in theory if you have a plot of land that can sustain, say, 100 people, but now it has 150 feeding off it. The only way for one group to survive is to either kill or drive off the entirety of the remaining group, so it doesn't matter if it's women or children that you're killing. The point is to convince the other group that they are more likely to survive by going elsewhere by making it so precarious for them to remain, or if that is not possible, then to wipe them all entirely. Raids do exactly that.
This is also why prisoners are rarely taken and often ritually killed right away - every prisoner you take is an extra mouth to feed. In an agricultural society, an extra mouth can feed itself because it requires comparatively little land to do so, but for pre-agriculturalists an extra pair of working hands is worthless if the land is already at capacity wrt what can be extracted from it (which is usually the case since populations grow until they reach that point).
Stuff like ethics of warfare, spiritual tradition, reputation etc is derived from all this. Cultures that practice this kind of raid warfare generally glorify it. A war leader who leads a successful raid to massacre an unprotected enemy village is a hero, not just to his own people, but more broadly as a model for other aspiring warriors in the larger culture. So things that we might consider as "disreputable" are not necessarily seen as such there.
That depends a lot on scarcity. If you are a male and you only get one chance at mating, you will probably fight to the death. If you will get plenty of other chances, then you might accept the results of a ritualised non-lethal combat (e.g. giraffes headbutting each other, rather than kicking). Its just evolution + game theory.
It's common among animal species for males to fight over females, but it's highly uncommon for them to fight to the death, because that is not evolutionary adaptive - it risks the individual as well as the genetic diversity of the group/species (and evolution is selecting for survival of the species, not the individual).
This is very wrong. Evolution is selecting for the total reproductive fitness of genes, and to a slightly lesser extent, individuals. There’s no mechanism that helps the process of evolution select for the survival or reproduction of the species. See any recent textbook on evolutionary biology, or read Dawkins, or even Darwin. I don’t know where you got this idea but it’s exactly wrong.
The "mechanism" is just the process of evolution itself, and how it plays out in practice, e.g. via punctuated equilibrium.
Over shorter timespans the gene pool of a breeding population incrementally drifts according to the success of individual genetics, but then once in a while, over multiple generations, something in the environment (disease, food, competition, etc) may change quickly and the gene pool as a whole, not just that of individuals, is thereby tested, with accumulations of previously benign changes sometimes suddenly becoming critical. In this way evolution is acting on the entire gene pool - of the species or more correctly of that interbreeding sub-population.
Success in evolution, the ability of the species as a whole to adapt and compete, also requires genetic diversity, not only to avoid inbreeding, but also to provide species level resilience, and species level ability to quickly adapt. e.g. It seems that the success of sexual reproduction is because it is a way to "game the game" by increasing genetic diversity and therefore improve along these axis of resilience and fast adaptation.
There are also social species, such as ourselves, where the social group becomes port of the individuals environment, and genetics best-fitted-to-the-environment becomes a group dynamic.
and one group ate their dead relatives’ brains at funerals so consistently that they gave themselves a mad cow type disease called kuru, which killed a large percentage of their population and then, within a few generations, evolved a genetic mutation[1] that protects against it, one of the fastest cases of natural selection ever documented in humans
The suggested evolution is:
* there is one ancestor with a gene that protects against kuru.
* children and mothers without that ancestor often die from kuru
* children of that ancestor have a much higher chance of survival
* eventually everyone is a child of that ancestor
* any children of that ancestor that didn't get the protective gene also eventually die out
The gene is selected for. There are no population effects.
The key part in the paper is where they mention adult men with the gene, because they are measuring the counterfactual of the many males that died because they didn't have that gene (males that ate brains as young kids but then died because they didn't have the gene from that ancestor).
The paper is hard to understand in part because of the confounding effects of males not eating the brains. Plus the confounder of stopping cannibalism in 1960.
The idea of "Group selection" is fundamentally wrong - regardless of how sensible the belief feels. Anybody using the words "group selection" is indicating their belief system, and they usually then have biased narratives to 'support' their belief.
[0] horrifically incorrect sciencedaily link in Wikipedia.
[1] We don't fucking evolve genetic mutations
Let's say that everyone has a skin color gene that makes them either red or blue. And a new predator turns up that only eats blue things. To you this is a tale about individuals, while it seems that an equally valid, and frankly preferable, view is this this isn't about individuals - it's about being red or blue and is a species level effect.
Words matter. Talking about "species level" is misleading because talking about an effect (blue phenotype) distracts us from the cause (a gene for blue).
And evolution is confusingly another step removed: the red survives because the blue did not.
Most of us struggle to see the counterfactual absence of a something.
The blue "species" never exists - our brains want to find groups and patterns. Our words mislead us.
The same thing is alluded to in the paper: the deaths of people without the gene is what is driving the gene to spread (through reproductive success of those that didn't die).
Reproduction is what matters (which death or sickness may interfere with).
Even the paper is confusing because it talks about 50 year old women (measuring survival bias; not whether they are expected to pass on genes at 50).
(reedits for clarity).
Your pink and blue example is actually a great model to work from. Think about the genes and the expression of those genes, and then think about what is being selected if all the blue animals are eaten.
Or think about what would happen if there was a mountain range, and pink animals were eaten on one side and blue ones were eaten on the other side.
Or think about what if one of the blue fathers has pink polka dots that gave it a 10% better chance of survival.
Always concentrate on watching that genes are passed on by reproduction - getting eaten doesn't have to be a problem if reproduction has already occurred (unless parental investment is needed or you get complicated like kin selection).
I am not a biologist. But 'The Selfish Gene' is one of my favourite books because of the concepts within. Unfortunately I think Dawkins went off the deep end later (with what I thought was religious zeal). The Extended Phenotype is even harder to read, but also worthwhile.
It is a fun topic because many phrases about evolution seem misleadingly about death rather than reproduction. And the meaning of the word evolution is absolutely twisted in everyday conversation. Ignoring the troubles with bible bashers. https://en.wikipedia.org/wiki/Survival_of_the_fittest - "fittest" has an unobvious meaning.
I believe that is wrong. Selection works on the level of the individual and their genes. Dawkins covered this extensively in at least one of his books. Any professional biologists care to comment?
You can tell it as a story (easier to teach) of individual success in surviving and having children, which isn't wrong, but it's also not the big picture.
There are a number of species where the female eats the male after mating - examples such as praying mantis and octopus. Both octopus males and females die after mating, the female after having protected the eggs, so it makes sense that she sometimes eats the male too (who is going to die anyway). But, examples like this are relatively rare, and for species specific reasons.
"Fighting to the death and mating are not the same!"
Your original question and your current statement are in confliction. Pick one.
This is the comment I was responding to.
The question was about pre-mating death matches between males, not post-mating snacking behavior of females.