The forests of Central Africa could be home to up to 920,000 Pygmies, according to researchers from UCL, Manchester Metropolitan University and the University of Malaga, who have conducted the first measured estimate of the population and distribution of these indigenous groups.
Pygmy musicians in the Congo Basin, Bottom: Mbendjele girls sharing out harvest [Credit: Jerome Lewis]
Up until now it has not been possible to determine the numbers and actual geographic ranges of Pygmy communities, because of their location in remote forest areas, mobility, lack of census data, and imprecise and partial sources of information. Pygmy communities live in rainforests across nine countries in Central Africa—an area of some 178 million hectares—where they make up a very small minority of the total population.
Despite the Pygmies' significance to humanity's cultural diversity as the largest group of active hunter-gatherers in the world, the new study, published in >PLOS ONE, is the first to predict how many Pygmies are likely to be found in the vast expanse of tropical forests in Central Africa. The study maps their distribution and identifies which areas are of ecological importance.
Dr Jerome Lewis (Hunter-Gatherer Resilience Project, UCL Anthropology), co-author of the paper, said: "This is a very underprivileged and neglected group of people many of whom have already lost their forest land, livelihoods and whose rich cultural traditions are seriously threatened in many regions.
"Information on their locations and population numbers are crucial for developing appropriate human rights, cultural and land security safeguards for them, as for other indigenous peoples."
Using a compilation of evidence collected by an unprecedented number of researchers, the authors generated the largest database of Pygmy camp locations throughout their known range.
As there are no known accurate censuses of Pygmy population the researchers used a statistical method, developed by paper co-author Dr Jesus Olivero (University of Malaga), to forecast the distribution of Pygmies in Central Africa. Based on species distribution models that investigate the relationship between environmental conditions and the distribution of organisms, the study is the first to apply this method to human societies and their cultural diversity.
Dr Olivero said: "By using tried and tested animal and plant distribution models we hope to promote a greater awareness of the importance of these too often ignored and marginalized groups in this region."
Professor John Fa (Manchester Metropolitan University), co-author, explained that understanding where and how Pygmy communities live is an important first step in supporting them and safeguarding their rights.
"It's important for all of the countries involved to come together to help support Pygmies' cultures and human rights to make sure they are respected and understood.
"At the end of the day, 900,000 people living in small groups in such a vast area can very easily be ignored, leading to their cultural extinction, and given the extraordinary role they have played in the human story since well before antiquity, we don't want that."
Source: University College London [January 15, 2016]
The worst land grab in decades in the Brazilian Amazon is threatening the survival of isolated tribes that have no contact with the outside world, a rights group said Wednesday.
Ranchers and settlers in the remotest reaches of northwestern Brazil are voraciously cutting down rainforest to farm crops, encroaching on the ancestral lands of three uncontacted groups, said Survival International [Credit: AFP/Yasuyoshi Chiba]
Ranchers and settlers in the remotest reaches of northwestern Brazil are voraciously cutting down rainforest to farm crops, encroaching on the ancestral lands of three uncontacted groups, said Survival International.
The land grab is also threatening another tribe, the Uru Eu Wau Wau, or "Harpy Eagle" people, that has only limited contact with the outside world, said the London-based group.
Warning the groups face "annihilation," it accused local politicians in the state of Rondonia of backing the deforestation, even though the area is officially designated as an indigenous reserve and sits within a national park, Pacaas Novas.
Because isolated peoples' immune systems have never been exposed to the outside world's diseases, the land grab risks causing devastating outbreaks, Survival said.
"Around the world, industrialized society is stealing tribal lands in the pursuit of profit. What's happening in Brazil is simply a continuation of the invasion and genocide which characterized the European colonization of the Americas," said the group's director, Stephen Corry.
The organization quoted a letter the Harpy Eagle tribe sent to Brazilian police, in which they call the land grab "extremely serious."
"We are very worried because the invasions are close to our villages and putting the lives of women, old people, children and men at risk," said the letter.
Experts estimate between 50 and 90 percent of the populations of Brazil's isolated tribes were wiped out when the government initiated contact with them in the 1970s and 80s—official policy at the time.
Today, the government tries to avoid any contact with isolated peoples, in order to protect them.
Brazil is home to some 900,000 indigenous people from 305 different ethnic groups.
The British Museum will open a major exhibition presenting a history of Indigenous Australia, supported by BP. This exhibition will be the first in the UK devoted to the history and culture of Indigenous Australians: both Aboriginal peoples and Torres Strait Islanders. Drawing on objects from the British Museum’s collection, accompanied by important loans from British and Australian collections, the show will present Indigenous Australia as a living culture, with a continuous history dating back over 60,000 years.
The objects in the exhibition will range from a shield believed to have been collected at Botany Bay in 1770 by Captain Cook or one of his men, a protest placard from the Aboriginal Tent Embassy established in 1972, contemporary paintings and specially commissioned artworks from leading Indigenous artists. Many of the objects in the exhibition have never been on public display before.
The objects displayed in this exhibition are immensely important. The British Museum’s collection contains some of the earliest objects collected from Aboriginal people and Torres Strait Islanders through early naval voyages, colonists, and missionaries dating as far back as 1770. Many were collected at a time before museums were established in Australia and they represent tangible evidence of some of the earliest moments of contact between Aboriginal people, Torres Strait Islanders and the British. Many of these encounters occurred in or near places that are now major Australian cities such as Sydney, Melbourne, Adelaide, and Perth. As a result of collecting made in the early 1800s, many objects originate from coastal locations rather than the arid inland areas that are often associated with Indigenous Australia in the popular imagination.
The exhibition will not only present Indigenous ways of understanding the land and sea but also the significant challenges faced by Indigenous Australians from the colonial period until to the present day. In 1770 Captain Cook landed on the east coast of Australia, a continent larger than Europe. In this land there were hundreds of different Aboriginal groups, each inhabiting a particular area, and each having its own languages, laws and traditions. This land became a part of the British Empire and remained so until the various colonies joined together in 1901 to become the nation of Australia we know today. In this respect, the social history of 19th century Australia and the place of Indigenous people within this is very much a British story. This history continues into the twenty first century. With changing policies towards Indigenous Australians and their struggle for recognition of civil rights, this exhibition shows why issues about Indigenous Australians are still often so highly debated in Australia today.
The exhibition brings together loans of special works from institutions in the United Kingdom, including the British Library, the Pitt Rivers Museum and the Cambridge Museum of Archaeology and Anthropology. A number of works from the collection of the National Museum of Australia will be shown, including the masterpiece ‘Yumari’ by Uta Uta Tjangala. Tjangala was one of the artists who initiated the translation of traditions of sand sculptures and body painting onto canvas in 1971 at Papunya, a government settlement 240km northwest of Alice Springs in the Northern Territory. Tjangala was also an inspirational leader who developed a plan for the Pintupi community to return to their homelands after decades of living at Papunya. A design from ‘Yumari’ forms a watermark on current Australian passports.
This exhibition has been developed in consultation with many Aboriginal and Torres Strait Islander individuals, Indigenous art and cultural centres across Australia, and has been organised with the National Museum of Australia. The broader project is a collaboration with the National Museum of Australia. It draws on a joint research project, funded by the Australian Research Council, undertaken by the British Museum, the National Museum of Australia and the Australian National University. Titled ‘Engaging Objects: Indigenous communities, museum collections and the representation of Indigenous histories’, the research project began in 2011 and involved staff from the National Museum of Australia and the British Museum visiting communities to discuss objects from the British Museum’s collections. The research undertaken revealed information about the circumstances of collecting and significance of the objects, many of which previously lacked good documentation. The project also brought contemporary Indigenous artists to London to view and respond to the Australian collections at the British Museum.
Neil MacGregor, Director of the British Museum said, “The history of Australia and its people is an incredible, continuous story that spans over 60,000 years. This story is also an important part of more recent British history and so it is of great significance that audiences in London will see these unique and powerful objects exploring this narrative. Temporary exhibitions of this nature are only possible thanks to external support so I am hugely grateful to BP for their longstanding and on-going commitment to the British Museum. I would also like to express my gratitude to our logistics partner IAG Cargo and the Australian High Commission who are supporting the exhibition’s public programme.”
Sex equality in residential decision-making explains the unique social structure of hunter-gatherers, a new UCL study reveals.
Agta household [Credit: Mark Dyble]
Previous research has noted the low level of relatedness in hunter-gatherer bands. This is surprising because humans depend on close kin to raise offspring, so generally exhibit a strong preference for living close to parents, siblings and grandparents.
The new study, published today in Science and funded by the Leverhulme Trust, is the first to demonstrate the relationship between sex equality in residential decision-making and group composition.
In work conducted over two years, researchers from the Hunter-Gatherer Resilience Project in UCL Anthropology lived among populations of hunter-gatherers in Congo and the Philippines. They collected genealogical data on kinship relations, between-camp mobility and residence patterns by interviewing hundreds of people.
This information allowed the researchers to understand how individuals in each community they visited were related to each other. Despite living in small communities, these hunter-gatherers were found to be living with a large number of individuals with whom they had no kinship ties.
The authors constructed a computer model to simulate the process of camp assortment. In the model, individuals populated an empty camp with their close kin - siblings, parents and children.
When only one sex had influence over this process, as is typically the case in male-dominated pastoral or horticultural societies, camp relatedness was high. However, group relatedness is much lower when both men and women have influence - as is the case among many hunter-gatherer societies, where families tend to alternate between moving to camps where husbands have close kin and camps where wives have close kin.
First author of the study, Mark Dyble (UCL Anthropology), said: "While previous researchers have noted the low relatedness of hunter-gatherer bands, our work offers an explanation as to why this pattern emerges. It is not that individuals are not interested in living with kin. Rather, if all individuals seek to live with as many kin as possible, no-one ends up living with many kin at all."
Many unique human traits such as high cognition, cumulative culture and hyper-cooperation have evolved due to the social organisation patterns unique to humans.
Although hunter-gatherer societies are increasingly under pressure from external forces, they offer the closest extant examples of human lifestyles and social organisation in the past, offering important insights into human evolutionary history.
Senior author, Dr Andrea Migliano (UCL Anthropology), said: "Sex equality suggests a scenario where unique human traits such as cooperation with unrelated individuals could have emerged in our evolutionary past".
Long before the advent of social media, human social networks were built around sharing a much more essential commodity: food. Now, researchers reporting on the food sharing networks of two contemporary groups of hunter-gatherers in the >Cell Press journal Current Biology provide new insight into fundamental nature of human social organization.
This photograph shows seafood gathering among Agata children [Credit: Rodolph Schlaepfer]
The new work reveals surprising similarities between the Agta of the Philippines and Mbendjele of the Republic of Congo. In both places, individuals maintain a three-tiered social network that appears to buffer them against day-to-day shortfalls in foraging returns.
"Previous research has suggested that social networks across human cultures are structured in similar ways," says Mark Dyble of University College London. "Across societies, there appear to be similar limits on the number of social relationships individuals are able to maintain, and many societies are said to have a 'multilevel' structure. Our work on contemporary hunter-gatherer groups sheds light on how this distinctive social structure may have benefited humans in our hunting-and-gathering past."
While previous studies have identified similarities in social structure across hunter-gatherer populations, the researchers say that the new work is the first to explore how hunter-gatherers' distinctive, "multilevel" social organization structures social life and cooperation in important activities such as foraging and food sharing.
"No other apes share food to the extent that humans do," says Andrea Migliano, principal investigator of the Leverhulme Trust-funded Hunter-Gatherers Resilience Project. "Hunter-gatherers' multi-level social structure exists in different groups, to help regulate these cooperative systems. Furthermore, multi-level social structures regulate social rules, friendship and kinship ties, and the spread of social norms, promoting a more efficient sharing and cooperation. Sharing is a crucial adaptation to hunter-gatherers' lifestyles, central to their resilience -- and central to the evolution of mankind."
Food sharing among the BaYaka [Credit: Gul Deniz Salali]
The Agta live in northeast Luzon, Philippines. Their primary source of protein is fish, supplemented by inter-tidal foraging, hunting, honey collecting, and gathering of wild foods. The Mbendjele live in an area spanning northern Republic of Congo and southern Central African Republic, where they hunt for meat in the forest. Both groups also trade wild-caught meat or fish for cultivated foods, including rice and manioc.
Dyble, Migliano, and their colleagues collected data on food sharing by living with the two communities for many months, making observations on how often households shared food with each other. From this they constructed social networks of food sharing.
"Although we had an idea of how camps split into food sharing clusters 'on the ground,' we were able to test these using algorithms which are able to identify sub-communities within the nine camps we studied," Dyble explains.
Their analysis showed that food sharing is closely related to social organization. In both communities, individuals maintain a three-tiered social network. First is their immediate household, most often consisting of five or six individuals, second is a cluster of three to four closely related households who share food frequently, and third is the wider camp.
Food processing among the BaYaka hunter-gathers [Credit: Gul Deniz Salali]
"Despite being from different continents and living in very different ecologies, both groups of hunter-gatherers had a strikingly similar social organization," Dyble says.
"Cooperation and especially food sharing are essential for survival in a hunting-and-gathering economy," Dyble says. "The proverb that 'it takes a village to raise a child' is certainly true for hunter-gatherers, who, without food sharing to mitigate the day-to-day shortfalls in foraging, could simply not survive."
Dyble says that they now intend to explore the structure of other types of social networks in the hunter-gatherer communities, such as cooperation in childcare, and their overlap with food sharing.
The traditional diet of Greenland natives — the Inuit — is held up as an example of how high levels of omega-3 fatty acids can counterbalance the bad health effects of a high-fat diet, but a new study hints that what’s true for the Inuit may not be true for everyone else.
A village on the coast of Greenland, where the native Inuit population traditionally ate diets high in omega-3 fats. Over thousands of years, they developed genetic mutations that allowed them to remain healthy despite the fatty diet, but this adaptation had other consequences, such as short height [Credit: Malik Milfeldt]
The study, which appears in the Sept. 18 issue of the journal Science, shows that the Inuit and their Siberian ancestors have special mutations in genes involved in fat metabolism. The mutations help them partly counteract the effects of a diet high in marine mammal fat, mostly from seals and whales that eat fish with high levels of omega-3 polyunsaturated fatty acids.
Those genetic mutations, found in nearly 100 percent of the Inuit, are found in a mere 2 percent of Europeans and 15 percent of Han Chinese, which means that these groups would synthesize omega-3 polyunsaturated fatty acids differently from the Inuit.
“The original focus on fish oil and omega-3s came from studies of Inuit. On their traditional diet, rich in fat from marine mammals, Inuit seemed quite healthy with a low incidence of cardiovascular disease, so fish oil must be protective,” said project leader Rasmus Nielsen, a UC Berkeley professor of integrative biology. “We’ve now found that they have unique genetic adaptations to this diet, so you cannot extrapolate from them to other populations. A diet that is healthy for the Inuit may not necessarily be good for the rest of us.”
These genetic mutations in the Inuit have more widespread effects. They lower “bad” LDL cholesterol and fasting insulin levels, presumably protecting against cardiovascular disease and diabetes. They also have a significant effect on height, because growth is in part regulated by a person’s fatty acid profile. The researchers found that the mutations causing shorter height in the Inuit are also associated with shorter height in Europeans.
“The mutations we found in the Inuit have profound physiological effects, changing the whole profile of fatty acids in the body, plus it reduces their height by 2 centimeters: nearly an inch,” said Ida Moltke, a University of Copenhagen associate professor of bioinformatics who is joint first author on the study. “Height is controlled by many genes, but this mutation has one of the strongest effects on height ever found by geneticists.”
Personalized diets
Nielsen noted that this is some of the clearest evidence to date that human populations are actually adapted to particular diets; that is, they differ in the way they physiologically respond to diets. Just as genome sequencing can lead to personalized medicine tailored to an individual’s specific set of genes, so too may a person’s genome dictate a personalized diet.
Seals and walruses were part of the traditional diet of the Inuit, as seen in this illustration of a native village on Canada’s Baffin Island, from the book Arctic Researches and Life Among the Esquimaux (1865) by Charles Francis Hall [Credit: University of California, Berkeley]
“People ask themselves whether they should be on a Stone Age diet, for example. The response may well depend on their genome,” Nielsen said.
Nielsen and his colleagues at UC Berkeley and in Greenland and Denmark came to their conclusions after analyzing the genomes of 191 Greenlanders with a low admixture of European genes (less than 5 percent) and comparing them to the genomes of 60 Europeans and 44 Han Chinese. They looked for mutations occurring in a large percentage of Inuit individuals but in few or no other groups, which indicates that the mutation spread throughout the Inuit because it was somehow useful to their survival while not essential in other groups.
One cluster of mutations — in genes that code for enzymes that desaturate carbon-carbon bonds in fatty acids — stood out strongly, said Anders Albrechtsen, an associate professor of bioinformatics at the University of Copenhagen and a joint project leader. Fatty acids are the fat in our diet, and occur in saturated, polyunsaturated and unsaturated forms, depending on whether the molecules’ carbon atoms are linked together with no, some or all double bonds. Saturated fats are considered bad because they raise levels of cholesterol in the blood and lower the “good” high-density lipoproteins (HDL), all of which leads to plaque formation and clogged arteries. Diets rich in polyunsaturated and unsaturated fats are linked to lower heart disease. Desaturase enzymes convert dietary fatty acids into fatty acids stored and metabolized by the body.
The mutations common in the Inuit, once known as Eskimos, decrease the production of both omega-3 and omega-6 polyunsaturated fatty acids, presumably to account for the high amount of these fatty acids coming from the diet. Changing production of one fatty acid affects all fatty acids, however, since they regulate one another in a complex way, Albrechtsen said.
Thus, while it’s not clear which specific gene or genes within the cluster is responsible for the alteration in fatty acid metabolism, he said that “when you change the genes that are involved in fatty acid synthesis, you change the whole conversation among fatty acids, and that has a lot of downstream effects.”
Adaptation to Ice Age living
The mutations seem to be at least 20,000 years old, and may have helped many groups of humans adapt to high-meat, high-fat, hunter-gatherer diets from large land and marine mammals high in certain types of omega-3 and omega-6 fatty acids, said Matteo Fumagalli, a researcher at University College London, who is joint first author of the study. They may have arisen among the original Siberians, who have lived in the Arctic for more than 20,000 years and arrived in Greenland when Inuit settled there about 1,000 years ago.
“We think it is a quite old selection that may have helped humans adapt to the environment during the last Ice Age, but the selection is far stronger in the Inuit than anywhere else,” said Fumagalli. “It’s fascinating that Greenlanders have a unique genetic makeup that lets them better use their traditional food sources.”
The researchers discovered another common mutation in a gene that is involved in the differentiation of brown, subcutaneous fat cells and brite fat cells, the latter of which generate heat. This may also have helped the Inuit adapt to a cold environment.
Author: Robert Sanders | Source: University of California, Berkeley [September 18, 2015]
Reciprocal food-sharing is more prevalent in stable hunter-gatherer camps, shows new UCL research that sheds light on the evolutionary roots of human cooperation.
Agta camp members [Credit: Daniel Smith, UCL Anthropology]
The research explores patterns of food-sharing among the Agta, a population of Filipino hunter-gatherers. It finds that reciprocal food-sharing is more prevalent in stable camps (with fewer changes in membership over time); while in less stable camps individuals acquire resources by taking from others -- known as 'demand sharing'.
Exploring social dynamics in the last remaining groups of present day hunter-gatherers is essential for understanding the factors that shaped the evolution of our widespread cooperation, especially with non-kin.
The study, published in the Royal Society journal >Open Science, is the first to report a real-world association between patterns of cooperation and group stability.
First author of the study, Daniel Smith (UCL Anthropology), said: "Cooperation between unrelated individuals is rare in animals, yet extensive among humans. Reciprocity -- the principle of "you scratch my back, I scratch yours" -- may explain this non-kin cooperation, yet requires stable groups and repeated interactions to evolve.
"Our research shows that hunter-gatherer cooperation is extremely flexible -- reflecting either reciprocity or demand sharing depending on the frequency of repeated interactions between camp members."
Agta camp member participating in study [Credit: Daniel Smith, UCL Anthropology]
The authors looked at two types of food-sharing data. Firstly, details of actual food-sharing from six Agta camps were examined to explore whether differences in camp stability predicted patterns of food-sharing. Secondly, games were also conducted in which individuals were asked to distribute resources between themselves and other camp-mates. These games were conducted with 324 Agta over 18 separate camps.
In one of the games, participants were shown their own picture, along with other randomly selected adults from camp. They were then given a number of small wooden tokens, each representing 125g rice, equal to the number of camp-mates' photos. Not every picture including the subject's could end up with rice on it, introducing a social dilemma regarding whether to share, as it would be impossible for everyone to receive rice. Participants then decided, token by token, whether to keep the rice for themselves, or to give to a camp-mate.
The results showed that, firstly, stable camps were more likely to display reciprocity in the actual food-sharing analyses. Patterns of food-sharing in unstable camps were not reciprocal, consistent with demand sharing, whereby individuals take resources from others rather than being given them. Secondly, individuals from more stable camps were increasingly likely to give resources to others and less likely to take resources in the games.
Despite differences in cooperation, individuals from both stable and unstable camps received resources from others. This distribution of resources among camp-mates is crucial for hunter-gatherers' survival. As foraging success is variable it is likely that, on any given day, an individual may return to camp with no resources. Food-sharing is therefore essential to reduce the likelihood of individuals going without resources for extended lengths of time.
Last author, Professor Ruth Mace (UCL Anthropology), added: "Food sharing and cooperation are at the centre of hunter-gatherers lifestyle. No other Apes share food or cooperate to the extent that humans do. A complex network of sharing and cooperation exists within camps and between camps in different hunter-gatherer groups, regulated by social rules, friendship ties, food taboos, kinship and supernatural beliefs. Sharing is a crucial adaptation to hunter-gatherers' lifestyles, central to their resilience -- and central to the evolution of humankind."
Source: University College London - UCL [July 13, 2016]
When members of the BaYaka Pygmies living in the northern Republic of Congo get sick, they don't just go to the doctor for a prescription. Instead, they rely on their shared knowledge of medicinal plants to help them get well. Now, researchers reporting in the Cell Press >journal Current Biology on September 8 have examined shared uses of those plants to understand how Pygmies have passed their extensive plant knowledge along from one person to the next.
The findings show the important role of marital bonds in passing information to otherwise distant families. There were some surprises, too.
"I wasn't expecting that plant uses would be so diverse," says Gul Deniz Salali (@DenizSalali) of University College London. She hadn't expected to find that plants would play an important role in executing social norms, either. "But many Pygmies told me that they used particular plants to detect and punish cheaters."
Salali was interested in exploring how hunter-gatherers accumulated the vast repertoire of plant uses that have helped them to survive in tropical rainforests. To find out, she and her colleagues examined the reported co-occurrence of plant uses between pairs of BaYaka Pygmy individuals based on extensively conducted interviews. Their study included reported uses of 33 different plants by 219 individuals living in four camps.
"We found that long-term pair bonds between men and women allowed otherwise distant families to combine information on medicinal uses of plants," Salali says. "Living in multi-family camps, on the other hand, enabled Pygmies to exchange and accumulate plant knowledge related to cooperative foraging and social beliefs."
The most commonly reported medicinal uses of plants were for treating digestive and respiratory disorders. The BaYaka also use some plants for collecting caterpillars or honey and as a poison for killing monkeys or fish. Other plants were used to regulate social life, including matters concerning lying or sexual taboos.
As an example, Salali says, some Pygmies use the juice extracted from a particular type of tree bark to detect and punish cheaters. "If someone cheated their partner, camp members would squeeze the poisonous juice into the person's eyes which could affect his or her vision. If his or her vision was affected, then people thought the person was guilty. I found that the knowledge on this type of plant use was widely shared among the campmates."
Knowledge of medicinal plants is mainly shared between spouses and other relatives, they found. But plant uses associated with foraging and social norms were often shared more widely among campmates, regardless of relatedness, playing an important role in camp-wide activities that require cooperation.
The researchers also found that BaYaka mothers who used more plants for treating certain diseases had healthier children.
Salali says her next step is to compare plant knowledge and use in hunter-gatherers living in varying proximity to market towns in Congo. "I have lived in some Pygmy camps that were located in the forest, and some larger ones that were located in a logging town," she says. "I am interested in exploring the biological and cultural adaptations of groups in transition from a nomadic hunter-gatherer lifestyle to a more sedentary farming way of life."
