I've been reading Mark W. Moffett's book The Human Swarm over the past couple of months. One of the things Moffatt points out in the book is that when we talk about hunter-gatherers, what we're really talking about is band societies.
Band societies are a specific type of social organization, and they are generally only found among hunter-gatherer (foraging) societies. In these societies, the main social unit is the band. A band typically consists of a few unrelated extended families, numbering in the range of perhaps 30-50 people. A band almost never got much bigger than around 65-75 individuals. If a band got too big, it would split up. There were no specialists except for perhaps healers and storytellers; for the most part, everyone in the band knew everything needed to survive. As Yuval Noah Harari notes, “The human collective knows far more today than did the ancient bands. But at the individual level, ancient foragers were the most knowledgeable and skillful people in history.”
Typically members of band societies were associated with one particular band for life, but they were free to leave it and seek membership in another band if and when they deem it necessary. Membership in a band was fluid and informal. Members of band societies say that this drastically cuts down interpersonal conflicts and keeps peaceful relations between band members. The interpersonal familiarity and easy-going camaraderie of bands meant that there was no need for formal legal or political structures. There was no such thing as a stranger. There was also no need for formal leaders. Behavior was socially determined by informal cues, with expulsion as the ultimate sanction. Decisions affecting all band members are made via debate and consensus. Thus democracy, rather than being a recent invention, was the original form of human political organization.
Moffett describes the band as kind of factory, able to provide for the needs of all its members on an ongoing basis:
Division of labor by age and sex was the backbone of the factory. In a human band almost invariably the men hunted large game or fished, while the women, often weighed down by breastfeeding children (which made hunting impractical), gathered the bulk of the band's calorie intake in the form of fruits, vegetables, and small prey like lizards and insects, and cooked dinner...
As a factory, each band was assembled redundantly: there could be multiple hunting and gathering parties, and the families performed many chores on their own. Because they had to be mobile to keep their stomachs full, the hunter-gatherers couldn't accumulate stuff, and didn't have ownership the way we think of it. People could possess just what they could lift—about 25 pounds of supplies is a figure sometimes given, the weight airlines permit for a carry-on bag...
Few tasks in a band factory demanded multiple players. When something had to made in steps, like a spear or lean-to, usually the same person (or maybe two) carried out the process from start to finish. Teamwork, when required at all, was seldom elaborate, although felling a giraffe or mammoth might have taken the coordinated efforts of several men, and perhaps butchering it required the ant-like participation of everyone available. (pp. 112-113)
Among jobs absent from bands were leaders. Anyone eager to make decisions for others was a problem for people who spent most of their lives in small groups day after day with little privacy. Ridicule and jokes were weapons deployed against those seeking to sway others, as often as they were used to deflate others shows of skill or superiority. To be influential, then, flamboyance wasn't an option; keeping the economy of a band humming along required nuanced social skill, with a goal to, in the words of one anthropologist, "persuade but not command." (117)
An upside of this factory life was that people weren't occupied with raising crops or struggling to take in excess food. They ended up with leisure time—a commodity that earned these nomads the moniker "the original affluent society." The only thing stockpiled was time to devote to social relationships.
The typical population of a band turns out to be ideal. Enough meat, produce, and goods were procured, processed, and exchanged on an average day to keep everyone fed and comfortable. Success became problematic when fewer than 15 or more than about 60 individuals resided in a band.
A band's size was self-regulating. The individuals and families, although interdependent, did as they wished. People could leave an overcrowded band to join another or go it alone for a time. (114)
The distinguishing feature of band societies, Moffatt explains, is that they have a fission-fusion dynamic. Fission-fusion is a process of coming together in larger groups and then breaking apart again: "Group formation is a highly dynamic process where group size and composition changes frequently within the lifetime of the group members as groups split (fission) and merge (fusion)." 
It is this fission-fusion dynamic, says Moffett, that is the principle characteristic of hunter-gatherers, and not how they get their food—what anthropologists refer to as their subsistence strategy. This actually came as a surprise to be because I had thought that what distinguished hunting and gathering societies was, well, hunting and gathering!
The feature that distinguished band societies from other modes of life wasn't specifically hunting or gathering, which people still enjoy, if only when they bag deer or excavate truffles. Nor were these hunter-gatherers totally distinct for their nomadism. Pastoralist tribes like the Huns could disperse to camps part of the year to secure pasturage for their domestic animals.
What most set them apart was the pattern of movement of their members: nomadic hunter-gatherers spread out by fission-fusion, with people roaming with considerable freedom.
Fission-fusion nevertheless generally took a regimented from for the nomadic hunter-gatherers of recent times, as it presumably did for those living prior to the invention of agriculture as well. People mostly clumped here and there in bands. Each band consisted of on average 25 to 35 individuals comprising several, usually unrelated nuclear families, often spanning three generations.
A person could visit other bands, yet tended to keep a long term connection with one. Shifts between bands usually came about with little effort but not often, a far cry from the eternally fluid movements of chimpanzees and other fission-fusion species characterized by ever-changing parties. (100-101)
As Moffatt alludes to, the reason the subsistence strategy is not the main defining feature of hunting and gathering societies is because hunting and gathering activities are not confined to what we typically think of as hunter-gatherer societies. All sorts of societies engage in hunting and gathering from time to time, including large, hierarchical ones based around growing crops. An Appalachian tobacco farmer who goes hunting for deer in the autumn, fishes in the local stream, and gathers edible wild plants and berries from the woods is engaging in hunting and gathering, but he is not a member of what we would think of as a hunter-gatherer society. More than likely, the earliest farmers supplemented their activities with a lot of hunting and gathering, especially if their crops failed.
The fission-fusion dynamic of a band society can be seen on multiple levels. For example, members of hunter-gatherer bands would typically break up into smaller groups called parties on a daily basis to forage, to hunt, to scout, to collect water, to build shelters, to look after children, to process and prepare food, or other basic tasks. The members of the band would reconvene at night, often around a crackling campfire to tell stories, sing songs, dance, and partake of the fruits of the day's labor.
At the other end of this fission-fusion dynamic, bands would congregate in larger groupings at various times of the year for lengths of time ranging from just a day to a few weeks or months at a time. These collective gatherings were typically associated with some kind of superabundant seasonal resource, whether it was game animals, plant resources like nuts or wild grasses, or water sources during the rainy season. When that resource was depleted or once again became scarce, the bands would break apart and go their separate ways, spreading out across the landscape in order to make a living until the next rendezvous. Burning Man can be seen as a modern manifestation of this phenomenon. Just like Burning Man (or any modern-day rock festival, really), there was typically a lot of singing and rhythmic dancing at such events (along with sex!).
Some of the versatility of the human expression of fission-fusion was on display when hunter-gatherer bands converged in aggregations of as many as a few hundred. These occasional social gatherings were staged during a season when resources were bountiful enough to sustain everyone for a few weeks. During this time, people massed together much like monkeys in a troop, except lodged in one place. The chosen site could be a watering hole or other productive location...(124)
If we think about nature, we can see abundant examples of fission-fusion behavior throughout the animal kingdom. Schools of fish, pods of whales, flock of birds, troops of monkeys, prides of lions, packs of wolves, herds of antelope, parliaments of elephants, shrewdnesses of apes, and swarms of insects are just of the few common examples that most of us can think of. In fact, fission-fusion behavior is so common that some biologists are starting to accept the idea that all animals exhibit fission-fusion behavior to some extent and that it is a spectrum rather than a single mode of social organization. In this view, there is no single fixed number for the size of an animal's social group; rather, it varies depending on the season as well as the circumstances such as the abundance of food, mates, and other resources.
Spreading out allows for a territory to sustain a greater population, as everyone in the society isn't clambering on top of each other to gain access to the same resources. Imagine what would occur if 100 chimpanzees stayed in one tight troop: the land they passed through would be picked clean, forcing them to move relentlessly and scramble for each tidbit like shoppers on Black Friday. Instead, the chimpanzees keep apart, meeting in temporary groups, called parties, of a large size only where they hot a resource jackpot, such as a tree weighed down with fruit (39)
The fission-fusion dynamic was first described by a biologist named Hans Kummer who was studying Hamadryas baboons. While these baboons are not as closely related to us as are chimpanzees and bonobos, they live in large, complex societies out on the African savanna—an environment very similar to that of our remote ancestors.
While troops of Hamadryas baboons can get quite large—up to 750 individuals—Kummer noticed that most of their socialization took place in several sub-groups. The smallest one was the one-male group, which was a semi-permanent association of a dominant male, his "harem," and their dependent offspring. Several one-male units together formed a clan, which also included solitary males. Males in a clan cooperated in defense against predators and fought off intruding rival males. A collection of several clans together formed a band, which stayed together for the part of the daily foraging expedition. Several clans would aggregate together to form a troop. While a band was a genuine social unit, troops were temporary aggregations of bands that would congregate at watering holes and overnight together at sleeping cliffs.
It was subsequently discovered that our closest living relatives—chimpanzees and bonobos—also lived groups that exhibited a high degree of fission-fusion. Chimps live in multi-male and multi-female groups. Sub-groups are permanent or temporary and can completely disappear after a while, or their members can join other members of the community to perform activities such as foraging, hunting, or traveling. The maximum size of a chimpanzee group is in the range of 100-150 individuals, with rare ones reaching up to 200.
The most fluid societies of any nonhuman primate are found among chimpanzees and bonobos, humanity's nearest living relatives. Chimpanzee communities, for instance are rarely seen together as a whole. Instead, subgroups of various sizes constantly coalesce and split based on moment-to-moment foraging and socializing needs. Subgroups of adult male chimpanzees separate from the group to cooperatively hunt mammalian prey or to patrol their border, and male-female dyads split off from the group to engage in sexual consortships with minimal mating competition. As a consequence of such fission-fusion processes, the composition of traveling chimpanzee parties is highly variable, often changing by the hour. 
Fission-fusion dynamics are intimately tied with social complexity. Unlike a herd dynamic where all the members are always in close proximity to one another, members of fission-fusion societies are spread out, yet still need to maintain social ties. The structure of a fission-fusion society is fluid and open, with members choosing whom to associate with, and for how long. Contacts in fission-fusion societies are less frequent and more flexible. To this end, members have to navigate a complex social world, forming factions, alliances, and coalitions on an ongoing, ever-changing basis. As a consequence, the social dynamics of fission-fusion societies are the most complex in the animal kingdom, much more than in herd societies or those of social insects. The social brain hypothesis argues that human intelligence was driven primarily by the need to manage and navigate the complex and protean world of social relationships, rather than just simply the needs of mere survival:
Freedom of movement allows social interactions to grow more complex, and it also pays off whenever personal relationships become hard to manage. Options open up that impossible for animals living "face-to-face"—monkeys, for example, that have no choice but to stay constantly together in a troop. Object to the local scene? A cunning chimpanzee of low social rank may find an opportunity to slip off to a quiet spot in his community's territory for a quiet liaison with a female. Even more surreptitiously, a gray wolf or male lion can sneak away to visit another pack or pride as a first step to defecting—transitioning to become a member of an other society can require this sort of painstaking duplicity. No surprise that many fission-fusion species are so bright. (38-39)
One unique solution that humans used to manage their fission-fusion societies was gossip. In the absence of face-to-face communication, one of the things which allowed band members to maintain social relationships across long distances was language. Gossip would have been especially important in this role. Without personal knowledge of all the members of the society, how could you know who was trustworthy and who was not? How could you keep track of who was attached, or who had a falling out? Gossip would provide a means of reputation assurance in the absence of direct contact. It would make sure that norms were enforced across the society, because anyone who violated them would quickly become the topic of gossip, just as they are today:
Gossip, in the strict sense of talking about third parties who are elsewhere at the time of the dialogue, appears to be uniquely human. Of even greater interest, most of our species' conversations—over two-thirds by some study estimates—focus on gossip.
But why is gossip necessary? Far from being mere small talk, gossip serves myriad vital functions within our fission-fusion societies, both at the individual level and at the group level. Gossip can facilitate social cohesion in the face of repeated separations, reminding individuals of the bonds they have with distant others. And it can also allow information to percolate through the group about the trustworthiness of each individual member, enabling listeners to keep track of others, despite limited first-hand observation.
Gossip, therefore, and maybe even language more generally, may have evolved specifically as an adaptation to the highly fission-fusion oriented societies of our hunter-gatherer ancestors. 
So, really, when we talk about hunters and gatherers, what we're really talking about is band societies and their fission-fusion dynamic. Based on similarities with chimpanzee and bonobo social organization, it is likely that this was the original mode of human social organization—and the one we have spent the most time in—going back to the days of our remote ancestors like Homo erectus some 1-2 million years ago.
For a long time the high degree of fission-fusion behavior among chimpanzees obscured the fact that they even lived in social groups, because the entire group was rarely seen together in one place. Instead, membership in chimp groups was initially seen by biologists as fluid and open, with no fixed or defined social boundaries. Primatologists like Jane Goodall were eventually able to discern that chimpanzees did indeed live in well-defined social groups, even if the composition of those groups was highly variable and changed over time.
In a similar fashion, anthropologists have often ignored, downplayed—or even denied—the fact that hunter-gatherers lived in societies with similar social boundaries. Some anthropologists have cited places like Australia's central desert—where the boundaries between different groups was often blurred and members of different groups criss-crossed each others' territories and frequently intermarried—to argue that hunter-gatherer societies were truly "open" and without any fixed boundaries, and thus were not true "societies" in the way we think of them.
Yet even the relatively fluid and open societies of Australia cited by anthropologists made a distinction between themselves and members of other groups, despite their lax attitude toward boundaries and relatively fluid membership. "There are two kinds of blackfellows," an Aboriginal elder informed anthropologist Mervyn Meggitt, "we who are the Walbiri and those unfortunate people who are not;" adding, "Our laws are the true laws; other blackfellows have inferior laws which they continuously break." The characteristics that anthropologists observed in Australia likely had more to do with low population density and a harsh environment requiring cooperation than the lack of distinct societies. As Moffett points out, "The border between France and Italy isn't as fraught as the one between North and South Korea, but it is present nonetheless." (p. 104).
The misunderstanding can be cleared up somewhat by making a distinction between a social group and the society. While small foraging bands were indeed the primary source of day-to-day social interactions, these bands were part of a wider milieu that could consist of potentially large groups of people, even if they were scattered across a wide geographical area. The Hadza hunter-gatherers of Tanzania, for example, are conscious of being part of singular people, even though they are affiliated with small, mobile bands.
My term "band society" could suggest that one band constituted a society, and that was true at times, but societies generally extended across a specific set of bands.
There are shelves of articles and books by anthropologists who write of hunter-gatherers based solely on what happened in bands, while ignoring how hunter-gatherer bands identified with a broader society. Sometimes, when they acknowledge the connections between bands at all, their solution is to claim that the nomads didn't have societies to speak of. This view often intimates that hunter-gatherer culture varied from one band to the next, with no wider human affiliations and nary a sharp boundary to be seen.
I find this doubtful. For one thing, all other human populations live in groups we call societies. Additionally, the hunter-gatherer bands documented over the last few centuries were affiliated with societies. Indeed, there is ample evidence that membership in societies was a crucial aspect of hunter-gatherer existence—one that is indispensable to understanding how the societies of today came to be.
I am not surprised these societies have been missed or misinterpreted. Until primatologists like Goodall deduced that chimps had societies from the animals' spacing and confrontations with outsiders, the consensus was that fission-fusion animals were "open-group species," without social borders. So it made sense that these human bands, whose movements were marked by fission-fusion as well, wouldn't have had them either.
Because the members of human band societies, as well as chimpanzees, rarely come together, finding out where a society stops and the next starts can be tough, but sharp separation in the memberships of societies are in place just the same.
Numerous accounts tell how hunter-gatherers of recent centuries felt secure in the presence of their "own kind." Asked who they were, typically a hunter-gatherer would give you the name for a community encompassing several, often a dozen or more, bands spread out over a wide geographic range. These band societies had populations ranging from a few dozen to perhaps a couple of thousand individuals. (103-104)...Because society membership is not always visible in daily life, societies, profoundly as important as they are, can be easy to miss. (218)
Moffett makes a distinction between band societies and tribes. Moffett applies the term "tribe" to settled village societies practicing a degree of horticulture, as well as nomadic pastoralists:
I distinguish band societies from tribes, a word typicially used...to describe simple settled societies, most of which were dependent on horticulture, where plants are cultivated in gardens rather than plowed fields, as well as more mobile pastoralists who tend domesticated herds. (98)
In this distinction, he follows the sociopolitical typology laid out by the eminent anthropologist Elman Service, who classified economies and socio-political organization into the following spectrum based on increasing population and social complexity:
foragers (hunter-gatherer): band society
Although it should be noted that these terms are not well-defined—even by anthropologists—and are often used interchangeably leading to confusion. A lot of times when people make references to their "tribe," what they are really referring to is the social dynamic of a typical band.
Foraging bands, then, can be seen as part of a larger shared people, or culture, whose members were partitioned between multiple different nomadic bands, and who exhibited a high degree of fission-fusion behavior. Unlike the members of a foraging band, not all members of the society would have known one another on an ongoing personal basis, yet they would recognize certain rights and obligations with respect to one another that they would not recognize with respect to people outside the society.
When it comes to our own species, there is no doubt that, by nature, we form fission-fusion societies...More than 99% of human history was spent in a hunter-gatherer existence, characterized by dynamically shifting social groupings at multiple levels.
At the highest tier in hunter-gatherer societies is the ethno-lingustic group or 'tribe', formed by several local 'bands' that fuse together when resources like water are clustered during dry seasons.
Bands themselves, which are made up of around 30 individuals, break up into smaller foraging parties during daily forays out of base camp. While some individuals remain at the camp to watch over youngsters and tend to the old or injured, the foraging parties gather edible plant material and hunt animals, afterward bringing the bounty back to a central place for sharing and redistribution.
Hunter-gatherer societies exhibit division of labor, though mostly between the sexes and not to the extent of highly specialized castes of social insects....Pair bonds, non-existent in the promiscuous chimpanzees and bonobos, enable men and women to assume distinct but complimentary ecological roles, splitting apart during the day and then pooling their assorted resources when they convene at night.
Aside from such ecological reasons for fission-fusion among hunter-gatherers, social reasons also abound. One of the most common is verbal disputes and fighting, which can result in individuals switching camps. The Hadza of Tanzania insist that fissioning into smaller camps is a surefire route to 'less bickering'. 
Because of this fission-fusion dynamic, hunter-gatherer societies were often assumed to be inherently quite small—only a few dozen people or so. Even today in some textbooks you will read the assertion that all human societies numbered no more than a few hundred or so individuals prior to the advent of agriculture and sedentism around ten thousand years ago. But this is completely wrong! In fact, we can think of a band society as kind of nation—one that is united by a shared culture rather than proximity, territory, or legal status as in our modern-day state societies. The band society is, as Benedict Anderson described nations in Imagined Communities, "…always conceived as a deep, horizontal, comradeship."
We think of nations, which academics call states, as having governments and laws. Band societies have neither, formally speaking. Still, hunter-gatherers expressed the same comfort and trust around the people of their own society that we do at present, and in many ways their societies are analogous to our nations.
The nineteenth century historian Ernest Renan believed nations to be a modern phenomenon, yet his definition of a nation as a strongly bonded people with a shared heritage of memories and a desire to identify collectively is an apt description of band societies, too...As linguist Robert Dixon informs us, again about the Aborigines:
"A [band society] appears in fact to be a political unit, rather than similar to a 'nation' in Europe or elsewhere--whose members are very aware of their 'national unity,' consider themselves to have a 'national language,' and take a patronizing and critical attitude towards customs, beliefs and languages that differ from their own." (103-105)
These band societies—and human social organization in general—can additionally be classified as multi-level societies, another term borrowed from biology and zoology.
A prime example is once again the Hamadryas baboons described above, who lived in several nested hierarchical groups, somewhat like a Russian matryoshka doll. The terms multi-level society and fission-fusion society are often used interchangeably, yet they are not identical. For example, forest-dwelling chimpanzees live in multi-male and multi-female groupings as noted earlier, and not true multi-level societies like savanna baboons.
In addition to baboons, multi-level societies have been observed among a wide variety of animals including other species of monkeys (snub-nosed and proboscis monkeys), zebras, elephants, giraffes and sperm whales, as well as multiple species of insects. Despite broad similarities between multilevel societies, the social dynamics might be very different. For instance, in geladas (another species of baboon), units are comprised of closely-related females; whereas in Hamadryas baboons, the strongest bonds are between male relatives in clans. African elephants form sophisticated multi-level groupings with mothers and their offspring forming the core units. Multilevel societies in mammals tend to be more common in species with a reliable food resource.
As with Hamadryas baboons, we can clearly recognize multiple social groupings in human societies. At the most basic level is the pair-bond, or the nuclear family, consisting of a man, a woman, and their dependent offspring (husband and wife are legal/cultural terms). Such pair bonds may or may not be permanent—the evidence indicates that humans are a serially monogamous but not a lifetime monogamous species. An extended family might be another level, consisting of siblings and their children. A band, then was a larger agglomeration of nuclear and extended families and other individuals attached to the group. The society would be the collection of all the bands who recognized themselves as part of the same basic people, or culture. Many band societies featured additional groupings as well, depending on the culture: "The people of many Australian societies...belonged to groups known as skins and moieties. Children were assigned to a skin next in sequence from that of one of their parents, and to a moiety based on their connection to an ancestral being and ties to a plant or animal species, connections that determined how they socialized and whom they could marry." (133)
Different levels [in multi-level societies] fulfill different adaptive functions and have evolved in response to different cost-benefit trade-offs. In humans, reproduction and close social support are the domains of the lowest tier; mid-level tiers are a pool from which one can choose partners for cooperative breeding and cooperative hunting, while cooperative defence is best served by higher-level tiers. In essence, higher levels of sociality can tackle problems that core structures cannot. 
In anonymous human societies comprised of hundreds of thousands, or even millions of unrelated individuals, it is this multi-level nature of human social organization that needs to be grasped in order to fundamentally understand human sociology, as well as human history. From this standpoint, it is the addition many more levels to the society that distinguishes more recent forms of human social organization rather than any sort of qualitative change in fundamental human social dynamics. Even members of agricultural and industrial societies are not so different from our stone-age or bronze-age ancestors.
Moffett argues that humans will always inherently from societies, and that they are intrinsic to our species. We cannot not be a member of a society, nor can everyone just live in just one indiscriminate society. We will always separate into groups of insiders and outsiders; it's in our nature. He cites the 1954 Robber's Cave experiment as an example. As Yuval Noah Harari remarked in Sapiens: “Evolution has made Homo sapiens, like other social mammals, a xenophobic creature. Sapiens instinctively divide humanity into two parts, ‘we’ and ‘they’.”
Over the long-term…the boundaries between societies trump the markers that define them (252)…For centuries, the pacific Island of Futuna, a low chunk of volcanic rock, at 46 square kilometers in size, offered space and resources for just two chiefdoms—Sigave and Alo. These societies, claiming opposite ends of the island, were in almost constant conflict, pausing only briefly now and then for island-wide ceremonies featuring a psychoactive drink made from a shrub native to the western Pacific...One might expect that in such a confined space, and over the course of so much time, one chiefdom would have conquered the other. That this never happened might bear on the human craving for an outgroup, if not an outright opponent. Could Alo have continued on without Sigave—a society in a vacuum? Would it, alone in the world, even be what we could call a society? (344)
[...] "A man must have a nationality as he must have a nose and two ears," wrote Ernest Gellner, a prominent thinker on nationalism. Gellner—who went on to argue, mistakenly, that the human need to be part of a nation is nothing more than a contrivance of modern times—never fathomed how right his statement was. The mind evolved in an Us-versus-Them universe of our own making. The societies coming out of this psychological firmament have always been points of reference that give people a secure sense of meaning and validation. (352)
Hunter-gatherers tend to take what might be best described as a chauvinistic view of their societies. Chauvinism is, "an irrational belief in the superiority or dominance of one's own group or people, who are seen as strong and virtuous, while others are considered weak or unworthy." (Wikipedia) Many hunter-gatherer groups have a term for their own people that has the connotation of "the real actual human beings," with terms for outsiders having the unfortunate connotation of 'sub-human', or even 'animal'. Psychological research has shown that people have a tendency to dehumanize those who break social norms, even if they are members of the same society. This assignment of people and things to various ranked categories seems to be an intrinsic pattern of the way humans think about the world and their place in it.
The architecture of minds built to perceive human groups as having their own essences doesn't grant equality to them all. We see our society and those of other people as falling into a hierarchy along with other living things, a notion codified in the Middle Ages as the great Chain of Being. Typically the royal We surmounts the chain (surpassed only by God and the angels). Other humans follow in a descending order, some of them, Aristotle announced, "as much inferior to their fellows...as beasts are to men." This hierarchy continues its plummet through the natural world, with "some animals," as Orwell wryly wrote in Animal Farm, "more equal than others."
The scale wasn't fashioned in an ancient Greek ivory tower; people intuited the universe was this way before the words were scratched on parchment. More than likely it's a basic feature of our psychology. Research shows that children think of people as superior to animals, and of outsiders as closer to their own group to animals. Furthermore the proneness of hunter-gatherers and tribal peoples to describe themselves as human suggests that this type of thinking is typical even among societies that are small and have much in common with their neighbors...Their use of epithets meaning nonhuman or animal also suggests those people felt entitled to treat at least some outsiders categorically as other species, an outlook that would naturally affect their relationships. (185-186)
Among hunter-gatherers, the Jahai of Malaysia call themselves the menra, or "real people." This is also the meaning of Dana-zaa, the name the Canadian Beaver Indians give their kind, and mihhaq, the word used by the Kusunda of Nepal. "even the gentle San [Bushmen] of the Kalahari," E.O. Wilson tells us, "call themselves the !Kung—the human beings"—true, yet even there the designation "human" applies not to every Bushman but merely those Bushmen who belong to the !Kung society… (184)
Given the practical payoff of a skill at humanizing animals (hunter, for example, often imagine what a deer is thinking to predict it’s next move), it’s a shock to discover just how readily people dehumanize other humans. The names many hunter-gatherers give themselves reflect how humans treat outsiders differently from, and usually inferior to, their own people or other groups they know and trust. Even the names many modern nations apply to their own citizens, such as Deutsch for the Germans and Dutch in the Netherlands, derive from the world in their languages for “human.” (185)
Because of the multi-level nature of human societies, exactly how many separate groups band societies were comprised of varies greatly between societies around the world. Some of them are very uniform, while others have multiple divisions, yet still see themselves as belonging to the same shared culture. This isn't confined to band societies; an American might identify as a Bostonian or a Midwesterner with clear distinctive behaviors from people in other parts of the country, yet still a member of the broader category of Americans.
Moffatt makes the paradoxical case that the more densely crowded a region is, the more social groups there will be, because people will have a greater need to differentiate themselves from their neighbors than they would in a sparely populated region where they would rarely, if ever, come into contact with strangers. New Guinea, for example, is home to hundreds of different societies—some no larger than a handful of small villages.
[T]he Hadza are all of one group; those we call the Ache had four societies; Tierra del Fuego's Yamana, now culturally extinct, had five; and the Andaman Islanders were originally separated into thirteen societies. Meanwhile, "the" Aborigines, spread across the Australian continent, had societies numbering five or six hundred (108)
At the same time, often people will be grouped together by outsiders in ways that the people themselves would not recognize (such as being grouped together by skin color, for example, or by geographic location):
[T]he Bushmen never felt themselves to be a single unit, worthy of a name and acknowledgement of affinity, any more than America's original inhabitants thought of themselves as Indians before Europeans coined the term. Bushmen was a category that the Bushmen, who thought of themselves in terms of their societies such as the !Xõ and the !Kung, didn't recognize. Even now they consider themselves Bushmen—or San, a pejorative name given to them by their Khoikoi neighbors, meaning rascal—only when they leave the bush to take jobs elsewhere. (107)
In a similar fashion, our grouping of all hunter-gatherers together falls into the same trap:
Hunter-gatherer societies have frequently been characterized by what they lack. Is the absence of agriculture and animal husbandry a sufficient motive for defining a universal societal type? Is the absence of domesticated resources symptomatic of a strong correlated syndrome of economic, social, and ideological patterns which invite the anthropologist's immediate recognition? Or does the term hunting-gathering throw together indiscriminately a welter of life ways? Does the aggrandizing Indian of the Northwest Coast of North America resemble the Pintupi man of Australia's Western Desert less than the New Guinea Highlands swidden cultivator, for example, or the Bedouin pastoralist? 
It's important to recognize that "hunter-gatherer" is a term of art. It simply refers to any society that does not depend on domesticated food resources, and that harvests most of its calories directly from nature. It does not mean that hunter-gathers are passive inhabitants of the landscape, as we'll see. Also, anthropologists have found numerous societies that do not depend on domesticated crops yet have a social structure very different from that of band societies, featuring things like sedentism, social rank, stored food resources, and immovable property (which has led to several important distinctions between them). It's important to keep in mind the extreme variability and variety of hunter-gatherer societies around the world when discussing them. Ultimately, the anthropologists cited above concluded that confronting their environments at low densities was a shared characteristic of hunter-gatherer societies, and that the distinction still had some validity for the purposes of study.
So, to summarize, when we talk about about hunter-gatherers, what we're usually talking about are band societies. Band societies are true societies, comprised of multiple roving bands—mobile groups of 30-60 individuals, both related and unrelated. Band societies are multi-level societies, and exhibit a high degree of fission-fusion. They were likely the original form of human social organization going back perhaps millions of years. All subsequent human societies developed out of these types of societies.
Band societies are a subgroup of what Moffett refers to as anonymous societies: societies in which not all of members need to personally know one another, and thus which can grow much larger than societies which require familiarity with all the members of the society. Very few animals besides humans and ants live in anonymous societies:
Commonalities with chimpanzees and other fission-fusion animals notwithstanding, the societies of hunter-gatherer bands were anonymous--they were dependent on markers of identity rather than the members' direct personal knowledge of each other. Individuals were regularly spread out to such a degree that not all the strangers they came across belonged to other societies.
This would suggest that hunter-gatherers conceived of their societies as being united around a common identity—language, culture, and other markers... (108)
We'll talk about markers and anonymous societies next time.
Citations in parentheses from The Human Swarm by Mark W. Moffett, Basic Books, 2019. All bolded emphasis mine unless otherwise noted.
 Current Biology Vol 19 No 15 (PDF)
 Current Biology Vol 19 No 15 (PDF)
 Current Biology Vol 19 No 15 (PDF)
 Resource Managers: North American And Australian Hunter-Gatherers, by Nancy M. Williams, Eugene S. Hunn.
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