Tag Archives: migration

Facebook ads can be used to gauge cultural similarity between countries

The cultural similarity between countries and international migration patterns can be measured quite reliably using Facebook data, a new study reports.

Image via Pixabay.

“Cultural hotspot” isn’t the first thing that pops into mind when thinking about social media for most of us. However, new research from the Max Planck Institute for Demographic Research in Rostock, Germany shows that data from Facebook can be used to gauge cultural closeness between countries, and overall migration trends.

And the way to do it is to track ads for food and drink on the platform.

We are what we eat

“[A] few years ago, after reading a work of a colleague using data from the Facebook Advertising Platform, I was surprised to find how much information we share online and how much these social media platforms know about us,” said Carolina Coimbra Vieira, a Ph.D. student in the Laboratory of Digital and Computational Demography at the Max Planck institute and lead author of the research, in an email for ZME Science.

“After that, I decided to work with this social media data to propose new ways of answering old questions related to society. In this specific case, I wanted to propose a measure of cultural similarity between countries using data regarding Facebook users’ food and drink preferences.”

For the study, the team developed a new approach that uses Facebook data to gauge cultural similarity between countries, by making associations between immigration patterns and the overall preference for food and drink across various locations.

They employed this approach as migrants have a very important role to play in shaping cultural similarities between countries. However, they explain, it’s hard to study their influence directly, in part because it is hard to ‘measure’ culture reliably. The traditional way of gauging culture comes in the form of surveys, but these have several drawbacks such as cost, the chances of bias in question construction, and difficulties in applying them to a large sample of countries.

The team chose to draw on previous findings that show food and drink preferences may be a proxy for cultural similarities between countries, and build a new analytical method based on this knowledge. They drew on Facebook’s top 50 food and drink preferences in various countries — as captured by the Facebook Advertising Platform — in order to see what people in different areas liked to dine on.

“This platform allows marketers and researchers to obtain an estimate of the number of Facebook monthly active users for a proposed advertisement that matches the given input criteria based on a list of demographic attributes, such as age, gender, home location, and interests, that can be customized by the advertiser,” Vieira explained for ZME Science. “Because we focus on food and drink as cultural markers, we selected the interests classified by Facebook as related to food and drink. We selected the top 50 most popular foods and drinks in each one of the sixteen countries we analyzed to construct a vector indicator of each country in terms of these foods and drinks to finally measure the cultural similarity between them.”

In order to validate their findings, the team applied the method to 16 countries. They report that food and drink interests, as reflected by Facebook ads, generally align with documented immigration patterns. Preferences for foreign food and drink align with domestic preferences in the countries from which most immigrants came. On the other hand, countries that tend to have few immigrants also showed lower preferences for foreign foods and drinks, and were interested in a narrower range of such products more consistently.

The team cites the example of the asymmetry between Mexico and the U.S. as an example of the validity of their model. The top 50 foods and drinks from Mexico are more popular in the U.S. than the top 50 U.S. foods and drinks are in Mexico, they explain, aligning well with the greater degree of immigration coming from Mexico into the U.S. than the other way around.

All in all, the findings strongly suggest that immigrants help shape the culture of various countries. In the future, the team hopes to expand their methodology to include other areas of preference beyond food and drink, and see whether these align with known immigration patterns.

“The food and drink preferences shared by Facebook users from two different countries might indicate a high immigrant population from one country living in the other. In our results we observed that immigration is associated with higher cultural similarity between countries. For example, there are a lot of immigrants from Argentina living in Spain and our measure showed that one of the most similar countries to Spain is Argentina. This means that foods and drinks popular between Facebook users in Argentina are also really popular in Spain,” she adds.

“The most surprising aspect of this study is the methodology and more precisely, the data we used to study culture. Differently from surveys, our methodology is timely, [cost-effective], and easily scalable because it uses passively-collected information internationally available on Facebook.”

Overall, the researchers say, this study suggests that immigrants indeed help shape the culture of their destination country. Future research could refine the new method outlined in this study or repurpose it to examine and compare other interests beyond food and drink.

“I would like to see our proposed measure of cultural similarity being used in different contexts, such as to predict migration. For instance, it would be interesting to use our measure of cultural similarity to answer the question: Do the migrants prefer to migrate to a country culturally similar to their origin country?” Vieira concludes in her email.”More generally, I hope our work contributes to increasing the development of research using social media data as an alternative to complement more traditional data sources to study society.”

The paper “The interplay of migration and cultural similarity between countries: Evidence from Facebook data on food and drink interests” has been published in the journal PLoS ONE.

Genomic studies uncover the tale of the first Bronze Age civilizations in Europe

Although they were set apart in cultural customs, architectural preference, and art, the earliest bronze-using civilizations from Europe were quite similar from a genetic standpoint, a new paper reports.

Reenactors living as a bronze-age family. Image credits Hans Splinter.

The exact details of the Early Bronze Age civilizations across the world aren’t always clear — and the peoples living around the Aegean Sea are no exception to this. One theory regarding this period is that these groups — mainly the Minoan, Helladic, and Cycladic civilizations — were introduced to new technology and ideas by groups migrating from the east of the Aegean, with whom they intermingled.

However, new findings show that these groups were very similar genetically, which wouldn’t support the idea that an outside group was present and overwhelmingly mixed with the locals, at least during the Early Bronze age (5000 years ago). In turn, this would mean that the defining technologies and developments of this era, the ones that took us from the stone to the copper/bronze age, were developed in the Aegean Sea region largely independently of outside influences. That being said, the team does report finding genetic evidence of ‘relatively small-scale migration’ from the East of this area.

Domestically-developed, foreign influences

“Implementation of deep learning in demographic inference based on ancient samples allowed us to reconstruct ancestral relationships between ancient populations and reliably infer the amount and timing of massive migration events that marked the cultural transition from Neolithic to Bronze Age in Aegean,” says Olga Dolgova, a postdoctoral researcher in the Population Genomics Group at the Centre Nacional d’anàlisi Genòmica (CNAG-CRG), and a co-author of the paper.

The transition from the late stone age to the early bronze age was mediated (and made possible) by the development of ideas such as urban centers, the use of metal, an intensification in trade, and writing. History is rife with examples of people moving around and spreading ideas as they go, so the team set out to understand whether the Early Bronze Age in the Aegean area was made possible by such a movement of people and ideas.

To find out, they took samples from well-preserved skeletal remains at archaeological sites throughout this region. Six whole genomes were sequenced, four of them belonging to individuals from the three local culture groups during the Early Bronze Age, and two from the Helladic culture. Furthermore, full mitochondrial genomes were sequenced from 11 other individuals who lived during the Early Bronze Age.

This data was pooled together and used to perform demographic and statistical analyses in order to uncover the individual histories of the different population groups that inhabited this area at the time.

The findings seem to suggest that early developments were in large part made locally, most likely growing on top of the cultural background of local Neolithic groups, and weren’t owed to a massive influx of people from other areas.

By the Middle Bronze Age (4000-4,600 years ago) however, individuals living in the northern Aegean area were quite different, genetically, from those in the Early Bronze Age. Half their lineage traced back to people from the Pontic-Caspian steppe, an area spanning to the north of the Black Sea from the Danube and to the Ural river. By this point, they were already highly similar to modern Greeks, the team adds.

In essence, the findings suggest that immigration started playing an important role in shaping local genetics after the peoples in the Aegean area had already transitioned from the stone to copper/early bronze age. With that in mind, these influxes precede the earliest known forms of Greek; this would suggest that although immigration didn’t play a large part in shaping technology and know-how during the early bronze age, it did play a central role in cultural matters as time went on, such as the emergence and evolution of Proto-Greek and Indo-European languages in either Anatolia or the Pontic-Caspian Steppe region.

“Taking advantage [of the fact] that the number of samples and DNA quality we found is huge for this type of study, we have developed sophisticated machine learning tools to overcome challenges such as low depth of coverage, damage, and modern human contamination, opening the door for the application of artificial intelligence to paleogenomics data,” says Oscar Lao, Head of the Population Genomics Group at the CNAG-CRG, and a co-author of the paper.

The advent of the Bronze Age in the Aegean region was a pivotal event in European history, one whose legacy still shapes much of its economic, social, politic, and philosophical traditions — and, by extension, the shape of the world we live in today.

Despite this, we know precious little of the peoples that made this transition, how they fared over time, or how much of them still resides in the genomes of modern-day groups such as the Greeks. The team hopes that similar research can be carried out in the Armenian and Caucasus regions, two regions ‘to the east of the Aegean’. A better understanding of peoples here could help further clarify what was going on in the Aegean at the time, helping us better understand the evolution of local technology, languages, customs, and genetic heritage.

The paper “The genomic history of the Aegean palatial civilizations” has been published in the journal Cell.

Tight border policies risk leaving millions of migrants stranded in countries hard-hit by climate change

Although it’s not the only one, climate change is increasingly recognized as one of the main drivers of migration by displacing people from vulnerable regions. Now, new research showed the influence border policy can have on climate migrants, with restrictive policies increasing vulnerability to climate conditions.

Credit Princeton University

Migration decisions are often multicausal and rarely due to environmental stress alone. Climate change may influence migration both directly and indirectly through various means, including economic and political ones. Migration patterns can respond to extreme weather events and long-term climate variability or change.

Researchers from Princeton University suggested that when migrants are allowed to move freely, both them and the countries they came from are less vulnerable and better off financially. But if border policies are more restrictive, migrants become more vulnerable and have fewer chances to prosper economically.

The team included migration into a standard model typically used by policymakers to estimate the social cost of climate change. They focused on two questions: What does exposure to climate change mean for people around the world? Who would be able to move, and who would be constrained to stay?

“In discussions about international migration and global climate policy, it seemed that many were looking through the lens of the people coming in, focusing only on the destination country, and not what it would mean for both the migrant population and origin countries,” said Hélène M. Benveniste, co-author.

The model is known as the Integrated Assessment Models (IAM), and uses a simplified representation of migration. In their version, the team included dynamics for both migration and remittance, cash being exchanged between people in the two countries.

Remittance is an important feature of the model, as cash received from family members abroad can be a powerful resource in developing countries. Exposure to climate change was measured by a mix between how people might be affected by it, where these people are, and where they might go, as well as how much money they have.

The researchers first tested the accuracy of the model by looking at different border policies, making them both easier and more difficult to cross than they are today. They also looked at the effects of border policies on different income levels and on people’s ability to relocate. Then, using actual migration flows from previous studies, they made projections up until the year 2100. They used a “gravity model” and took into account economics, demography, migration, and income differences between places to determine the number of people that would migrate.

They found that vulnerability and exposure to climate change impacts were higher in developing countries. Most migrants during the 21st century moved to areas where they are less exposed to such impacts. The researchers couldn’t figure out how many of these migrants moved because of climate change, as many relocated for other reasons as well, including financial ones.

The results showed that open borders have a positive impact on developing countries themselves, especially in places like Central America, Southeast Asia, and small island nations. When people can move freely, they tend to send more money “back home,” which provides an important source of income for the country of origin.

“Considerations of unequal levels of development across regions are crucial to understanding international migration flows in conjunction with climate change damages. Indeed, reducing inequality between countries would also decrease the need and benefit to use international migration as an adaptation solution to climate change impacts,” the researchers wrote.

The study was published in the journal PNAS.

Nordic Bronze Age helped define migration patterns in Denmark

The beginning of the so-called Nordic Bronze Age, a period of unprecedented economic growth in Scandinavia in the 2nd millennium BC, helped define the migration patterns in present-day Denmark, according to a study by Karin Frei of the National Museum of Denmark and colleagues.

Credit: Flickr

Western Europe experienced a period of significant migration during the 2nd and 3rd millennia BC, including the movement of steppe populations into more temperate regions. Starting around 1600 BC, southern Scandinavia became closely linked to long-distance metal trade elsewhere in Europe, which gave rise to a Nordic Bronze Age.

“Our data indicates a clear shift in human mobility at the breakthrough point of the Nordic Bronze Age when an unprecedented rich period in southern Scandinavia emerged. This suggests to us that these aspects might have been closely related,” Frei said.

Frei and colleagues investigated in their study whether patterns of migration changed during this Nordic Bronze Age. They examined the skeletal remains of 88 individuals from 37 localities across present-day Denmark. Since strontium isotopes in tooth enamel can record geographic signatures from an early age, analysis of such isotopes was used to determine individuals’ regions of provenance.

Radiocarbon dating was used to determine the age of each skeleton and physical anthropological analyses were also conducted to add information on sex, age and potential injuries or illness.

From 1600 BC onwards — around the beginning of the Nordic Bronze Age — the strontium signatures of migrants became more varied, an indication that this period of economic growth attracted migrants from a wide variety of foreign locales, possibly including more distant regions.

The authors suggested that this might reflect the establishment of new cultural alliances as southern Scandinavia flourished economically. They propose that further study using ancient DNA may further elucidate such social dynamics at large scales.

“Around 1600 BC, the amount of metal coming into southern Scandinavia increased dramatically, arriving mostly from the Italian Alps, whereas tin came from Cornwall in southern England. Our results support the development of highly international trade, a forerunner for the Viking Age period,” co-author Kristian Kristiansen said.

Credit: Flickr.

Ancient Neanderthal genomes reveal surprising twist in their settling of Europe

Credit: Flickr.

Credit: Flickr.

Recent digs and studies have revealed that Neanderthals, our close cousins, lived complex lives, which were very similar to our own. Neanderthals are now known for crafting complex tools, jewelry and other symbolic objects, or engaging in cultural practices such as ritual burials and cave art. And although Neanderthals went extinct more than 50,000 years ago, much of their rich history is still waiting to be uncovered — from their genes.

Most recently, researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, sequenced the nuclear genome of two Neanderthal individuals who lived around 120,000 years ago. One genome sequence was performed on the femur of a male discovered in 1937 in Hohlenstein-Stadel Cave, Germany, the other on the maxillary bone of a girl found in 1993 in Scladina Cave, Belgium.

Most of our DNA is stored in the cell’s nucleus, while some of it is also stored in the mitochondria, i.e. mitochondrial DNA (mtDNA). Nuclear DNA is inherited equally from both parents; a child will inherit 50% of their nuclear DNA from the mother and the other 50% from their father. Meanwhile, mtDNA is passed on exclusively from the mother’s side.

The nuclear genomes of the two Neanderthals — the oldest genomes that scientists have sequenced thus far — revealed a surprising picture. Basically, these early Neanderthals in Western Europe were more closely related to some of the last Neanderthals living in the same region some 80,000 years ago than they were to contemporaneous Neanderthals living in Siberia.

The femur of a male Neandertal from Hohlenstein-Stadel Cave, Germany. Credit: Oleg Kuchar, Museum Ulm.

The femur of a male Neandertal from Hohlenstein-Stadel Cave, Germany. Credit: Oleg Kuchar, Museum Ulm.

“The result is truly extraordinary and a stark contrast to the turbulent history of replacements, large-scale admixtures and extinctions that is seen in modern human history,” said Kay Prüfer of Max Plank who supervised the study.
On the other hand, the mitochondrial genome of the Neanderthal from Hohlenstein-Stadel Cave has 70 mutations that distinguish it from the mtDNA of other early Neanderthals. This suggests that early European Neanderthals may have inherited some of their DNA from a hominid that’s yet to be discovered.
“This unknown population could represent an isolated Neanderthal population yet to be discovered, or may be from a potentially larger population in Africa related to modern humans,” explains Stéphane Peyrégne who led the analysis.
The findings suggest that Neanderthal populations in Europe went through multiple waves of replacement. But where did these new populations come from and were these turbulent re-populations limited to a particular region? Whatever the case may be, it becomes clearer with each new study that admixture was the norm in both Neanderthal and modern human populations (which today contain at least 2% Neanderthal DNA in their genomes).
Credit: Posth et al./Cell.

Ancient DNA reveals two previously unknown migrations into South America

Credit: Posth et al./Cell.

Credit: Posth et al./Cell.

Scientists analyzed the ancient DNA of individuals who lived in Central and South America up to 10,000 years ago and found that these regions were settled by at least three waves of migration. The studies paint a rich and diverse history of the Americas, suggesting that the people who formed these migratory waves branched out of a single population that crossed the Bering Strait into North America about 15,000 years ago.

“Our work multiplied the number of ancient genomes available from these areas by about 20, giving us a much more comprehensive picture of indigenous history in the Americas,” co-senior author David Reich, a geneticist at Harvard Medical School and the Howard Hughes Medical Institute, said in a statement. “This broader dataset reveals a common origin of North, Central, and South Americans as well as two previously unknown genetic exchanges between North and South America.”

The DNA collected from 49 individuals who lived in Belize, Brazil, the Central Andes, and southern South America shows that they all originate from the same ancestral population that colonized North America. In and of itself, this fact is not particularly remarkable because scientists have always known that Central and South America were peopled by a migration that moved southward. However, what was truly surprising about the findings of three new ancient DNA studies, all published this week (Cell, ScienceScience Advances), was that there were multiple distinct migratory movements — some that mixed, others that formed new lineages.

Archaeologists believe that the Clovis people were the first to pass through the land bridge between Siberia and Alaska, which is now underwater, settling in the lower 48 states some 13,000 years ago. The Clovis culture was named after flint spearheads found in the 1930s at a site in Clovis, New Mexico. These mammoth-hunting people are considered to be the ancestors of most of the indigenous cultures of the Americas. Now, the new genomic analysis has yielded fresh insights into how Clovis people may have spread across the Americas.

Researchers compared the genome of a Clovis toddler who lived in Montana about 12,700 years ago to the earliest genome analyzed from South and Central America dating to between 9,000 and 11,000 years ago. The analysis revealed a common ancestry between the remains found in Montana and Lagoa Santa in Brazil, which suggests that the Clovis made a major impact much further south. Previously, anthropologists believed that the people at Lagoa Santa originated from a separate migration from Asia.

“We weren’t expecting to find a relation to people associated with the Clovis culture in South America,” says co-first author Nathan Nakatsuka from Harvard. “But it seems the expansion of the Clovis-associated lineage extended to parts of Central and South America.”

From around 9,000 years ago, however, the Clovis culture-associated ancestry completely disappeared in Peru. We don’t know what was the cause of such a dramatic large-scale population replacement but what seems certain is that the region was populated by a separate wave of migration, which showed remarkable continuity compared to Eurasia and Africa.

“There is remarkable continuity between earlier and later skeletons with South Americans today,” said Cosimo Posth, an archaeogeneticist from the Max Planck Institute for the Science of Human History. “For example, modern-day Quechua and Aymara from the Central Andes can trace their ancestry back to the ancient people of the Cuncaicha site from 9,000 years ago onwards. This is a longer-standing continuity than you see in other continents.”

The big question right now is why the branching occurred so fast. What seems certain is that the narrative of humanity’s distribution across the Americas is far more complex than meets the eye.

“We’re very enthusiastic about the prospects for a much richer understanding of American population history, but this is still a vast region full of geographic and chronological holes,” says Reich. “We’d like to collect more genetic material from earlier and later sites and from more countries, such as Colombia, Venezuela, and other parts of Brazil. We also want to examine the evolution of genetic traits over time.”

Where crows go in the winter — and other stories about migration

When winter comes, not all crows react the same. Some stay right where they are, toughing out the frigid days as they best can. Others choose to move to warmer areas, returning only when the cold has faded away. This is called a partial migration.

Image credits: M. Jones.

Animal migration is a spectacular behavior that has fascinated humans since times immemorial. But most people aren’t aware that the most common form of migration in animals is actually partial migration — where just a fraction of the individuals migrate, and the other stays in place. This phenomenon is almost ubiquitous amongst migratory animals and has been reported in some species of fish, birds, amphibians, insects, and mammals. Despite all this, partial migration remains relatively understudied.

In order to address this shortcoming, Hamilton College’s Andrea Townsend and her colleagues captured crows in large winter flocks in Utica, New York, and Davis, California, fitting them with satellite transmitters to track their movements. The scientists also collected blood and feather samples.

Researchers found that most crows do migrate — not just to escape trying weather, but to breed. In total, 73% of western crows and 86% of eastern crows migrated at least some distance to breed, with an average journey of around 500 kilometers.

Interestingly, birds that stayed put one year also stayed put the next one — and the same thing was observed about migrating crows. It seems that their migratory behavior doesn’t change from year to year, and the birds don’t change strategies. However, they were more flexible when it came to where they spent the winter.

Researchers also note that tracking crows’ migrations (and that of other urban-dwelling creatures) are more important than ever because their migratory patterns are affected by climate change and increasing levels of urbanization.

“If you live in a place, usually a city, with a huge winter flock of crows, you are seeing migratory birds that came south for the winter as well as your local, year-round crows,” says Townsend. “Personally, I find the sight of an 8000-crow roost exhilarating, but if they or their feces are driving you crazy, you can at least take comfort in knowing that most of them will disappear in early March.”

But perhaps the most intriguing part is how much we still don’t know about these common creatures. We see them ever so often, but they’re still shrouded in mystery.

“It is surprising how much remains unknown about the seasonal movements of most partial migrant species, and this is especially true for variability among populations,” adds the Smithsonian Migratory Bird Center’s Emily Cohen, an expert on migration patterns who was not involved with the study. “This kind of information about populations-specific annual movements is not trivial to collect, but is fundamental to understanding most aspects of the evolution and ecology of species.”

The study “Where do winter crows go? Characterizing partial migration of American Crows with satellite telemetry, stable isotopes, and molecular markers” has been published The Auk: Ornithological Advances.

giraffe

The story of human dispersal out of Africa started 60,000 years earlier than previously thought

Most people are familiar with the so-called “Out of Africa” (OoA) hypothesis according to which our early Homo sapiens ancestors dispersed around the world by leaving an African hotspot 60,000 years ago. But the story of how our species came to conquer the world has far more complex beginnings, scientists say.

giraffe

Modern humans left Africa in multiple minor waves prior to a great migration which occurred 60,000-50,000 years ago. Credit: Pixabay.

In the past fifteen years, a great deal of archaeological and paleontological evidence, as well as genetic findings, have placed a question mark on the “Out of Africa” hypothesis. Homo sapiens fossils dated between 70,000 to 120,000 years old were discovered in China and southeast Asia, and some even as far as Australia dated to 60,000 years ago. Human fossils found in the Skhul and Qafzeh caves in Israel that predate the OoA timeframe are also worthy examples. If humans had barely begun to exit Africa 60,000 years ago, how can we explain these other findings?

At the same time, such fossils are few and far between, whereas there’s a treasure trove of fossils and artifacts that document a human dispersal out of Africa around 60,000 to 50,000 years ago.

The most plausible explanation is that humans indeed embarked on a massive wave of migration around that time, possibly spurred by a changing climate. However, before this truly massive undertaking, early hunter-gatherers must have migrated in smaller waves.

The baby steps

This is the conclusion of researchers from the Max Planck Institute for the Science of Human History and the University of Hawai’i at Manoa who reviewed the plethora of new discoveries reported from Asia over the past decade.

“The initial dispersals out of Africa prior to 60,000 years ago were likely by small groups of foragers, and at least some of these early dispersals left low-level genetic traces in modern human populations. A later, major ‘Out of Africa’ event most likely occurred around 60,000 years ago or thereafter,” explains Michael Petraglia of the Max Planck Institute for the Science of Human History in a statement. 

Various migratory pathways associated with modern humans dispersing across Asia during the Late Pleistocene. Credit: Bae et al. 2017.

Various migratory pathways associated with modern humans dispersing across Asia during the Late Pleistocene. Credit: Bae et al. 2017.

Human migrations across the Old World are further complicated by the numerous proven interbreeding events. We now know for sure that humans not only interbred with Neanderthals but also with other close relatives like the Denisovans and a mysterious unidentified population of pre-modern hominins. All non-Subsaharan humans alive today have 1-4% Neanderthal heritage, while modern Melanesians have an average of 5% Denisovan heritage. Though not included in this present review, there’s evidence that around 2% of the Papua New Guinean genome contains traces of modern human dispersals earlier than 60,000 years.

These interactions suggest that humans interacted closely with different hominin populations present in Asia during the Late Pleistocene.

“Indeed, what we are seeing in the behavioral record is that the spread of so-called modern human behaviors did not occur in a simple time-transgressive process from west to east. Rather, ecological variation needs to be considered in concert with behavioral variation between the different hominin populations present in Asia during the Late Pleistocene,” explains Christopher Bae of the University of Hawai’i at Manoa.

The authors plan on conducting new research in areas across Asia which have yet to be investigated. There are still many unanswered questions but more multidisciplinary research might help fill the gaps in the evolutionary records. For instance, why did these initial minor dispersals fail? Were early populations assimilated by the later and larger migratory wave or did they just disappear in isolation? These are certainly exciting times to be a researcher in the field, that’s for sure, concludes Bae.

Scientific reference: C.J. Bae at University of Hawai’i at Manoa in Honolulu, HI el al., “On the origin of modern humans: Asian perspectives,” Science (2017).

Monarch Butterfly.

Death of a dynasty: west North America lost over 95% of its monarch butterflies in 35 years

The end is nigh for the monarch butterfly.

Monarch Butterfly.

Image credits Billings Brett / USFWS.

Tradition dictates that every year, the American West Coast dons a fluttery, black-and-orange coat with the migration of the monarch butterflies (Danaus plexippus). But in recent decades, that coat has become thinner and frailer, an indication that something isn’t quite right with the insects. A decline in their numbers first became evident around the 1980s, and by the 1990s, nature lovers started to report a visible reduction in the swarms of butterflies migrating south for winter.

Now, a team of researchers from the Washington State University warns that we may be witnessing the last migrations of the monarchs, as the species’ numbers have declined to an all-time low.

A sight to behold

Every autumn, the insects make their way from all across the continent to sunnier California, where they spend the winter basking in the sun. Eastern populations of the monarch are known to hop the border into Mexico instead. After the cold months pass, the butterflies make their way back to the US and Canada, sup on spring flowers, lay their eggs on milkweed — and then do it all over again when winter looms.

No matter where they travel to, however, the journey takes D. plexippus over thousands of kilometers of the US countryside, attracting nature lovers everywhere. The butterflies gather in huge numbers and literally cover entire sections of woodland in a riot of black-and-orange wings. The migration is so strikingly beautiful that the event was often caught on film for nature documentaries.

Monarch flood.

Image via Youtube / National Geographic.

Sadly, such footage is the only place you can enjoy the sight today. Back in the 1990s, nature lovers attending the butterflies’ migration were starting to notice that the insects were dwindling in number. This begged the question: what’s happening to the monarchs?

To find out, a team of researchers led by Cheryl Schultz from Washington State University, Vancouver, worked with communities along the coast of California to pool records on butterfly numbers gathered by volunteers from across the state since the 1980s. Because the different groups involved in the migration take various paths — some even overwinter in forest groves west of the Rockies, for example — the team also drew on data gathered by the Xerces Society for Invertebrate Conservation, which recruited volunteers to do a yearly count of the “monarch populations overwintering along the California coast” since 1997.

Royally screwed

They fed this data into a mathematical model designed to dampen the data’s noise — minor fluctuations in numbers caused by the natural year-to-year changes in the pockets of butterflies — to get a good look at the long-term trends of the overall species. Their results paint a very grim future for the monarch: the team reports that their numbers have declined to less than 5% what they were in the mid-1980s, pushing the monarch dangerously close to extinction.

“In the 1980s, 10 million monarchs spent the winter in coastal California,” says lead researcher Cheryl Schultz from Washington State University Vancouver. “Today there are barely 300,000.”

“This study doesn’t just show that there are fewer monarchs now than 35 years ago. It also tells us that, if things stay the same, western monarchs probably won’t be around as we know them in another 35 years,” says Schultz.

Because they looked at population numbers alone, the team can’t offer an answer as to why the butterflies are dying off. It’s likely a ‘death by a thousand cuts’ scenario. Habitat loss and a decline of the summer milkweed which they use to reproduce due to shifting climate and land clearing, along with the effects of harmful pesticides, are wrecking havoc on the insects. More research is required to pinpoint the exact cause, but the findings may come in too late to help save the monarch. A report published by conservation non-profit Center for Biological Diversity concluded that “there is a substantial probability that the eastern monarch butterfly population could decline to such low levels that they face extinction. Researchers estimate that there is between 11 percent and 57 percent probability that the monarch migration could collapse [by 2036].”

The findings we’ve covered here today now show that the western populations of the monarch butterflies are in even more dire shape than the eastern populations, the team notes. Significant conservation efforts are needed to help save the species, and they’re needed sooner rather than later. The US Fish and Wildlife Service is monitoring the situation but is yet to list the monarchs as an endangered species.

The paper “Citizen science monitoring demonstrates dramatic declines of monarch butterflies in western North America” was published in the journal Biological Conservation.

north american settlers archaeology

Found: oldest settlement in North America, confirms local tribe history

When Alisha Gauvreau, an anthropology PhD student at the University of Victoria started excavating a rocky spit on Triquet Island, some 500 kilometers northwest of Victoria, she didn’t really know what to expect, but this definitely surpassed even her most ambitious expectations.

north american settlers archaeology

The first North American settlers might have arrived on the coast and not on a frozen land bridge through Siberia, as was previously believed. Image via Wikipedia.

The archaeological team patiently dug and then sifted through meters upon meters of soil and peat, before they finally found something interesting: the charred remains of an ancient hearth. As it so often happens, that’s just the start of interesting things. Not long after that, Gauvreau and collaborators found a trove of items, including tools for lighting fires, fish hooks, and spears, all dating back from 14,000 years ago.

“I remember when we get the dates back and we just kind of sat there going, holy moly, this is old,” said Gauvreau.“What this is doing is just changing our idea of the way in which North America was first peopled.”

The findings tell an interesting story, that of an early migration occurring on British Columbia’s ancient coastline, and challenges some of the most widely-held beliefs about humans migrating to North America. The classic story is that humans arrived some 13,000 or 14,000 years ago, crossing a land bridge that connected modern-day Siberia to Alaska. But more and more research is starting to challenge that belief. The challenging theory is that people arrived on the coast, settling down on a coastal strip of land that did not freeze during the ice age. In a radio interview with the CBC, Gauvreau says that her research adds significant weight to that idea.

“[A]rchaeologists had long thought that … the coast would have been completely uninhabitable and impassible when that is very clearly not the case,” she explains.

To make things even more interesting, these findings support the ancient, oral, histories of aboriginals. The Heiltsuk people are the descendants of a number of tribal groups who came together Bella in the 19th century. For countless generations, Heiltsuk First Nation elders have told the story about how their ancestors arrived in the area, on the coast.

“[I]t reaffirms a lot of the history that our people have been talking about for thousands of years,” William Housty, a member of Heiltsuk Nation, proudly stated.

Now, anthropologists and archaeologists want to explore more of the coast and the coastal islands, to further document how the migration happened.

Credit: CHRIS BUZELLI, Nautilus.

First humans might have arrived in North America 10,000 years earlier during the Last Glacial Maximum

Credit: CHRIS BUZELLI, Nautilus.

Credit: CHRIS BUZELLI, Nautilus.

Anthropologists agree that the first human settlers arrived in North America from Asia through Beringia, a vast region stretching from the Lena River in Siberia to the Mackenzie River in the Yukon Territory. These ‘first people’ originated in Siberia, according to palaeogenetic analyses, but it’s still unclear when the first wave of migration happened. Archaeological evidence seems to suggest humans crossed a small land bridge between Siberia and Alaska some 14,000 years ago during the last glacial period. However, a new study that analyzed artifacts collected at the Bluefish Caves suggests the dispersal might have first started during the Last Glacial Maximum, some 25,000 years ago.

Bones don’t lie

The Bluefish Caves, a site consisting of three small caves located in the northern Yukon, first came into the limelight when excavations performed between 1977 and 1987 made a case the site was occupied by humans during the Last Glacial Maximum (LGM). The hypothesis, however, did not stand up to scrutiny and proved controversial. No other sites of similar age were found in Beringia and some scientists disputed the dating, as well as the anthropogenic signature of the bones found there.

Canadian researchers from the University of Montreal revisited the “Beringian standstill hypothesis” and performed  taphonomic analyses of the fauna remains unearthed from the caves beneath a layer of  loess —  “fine particles of aeolian silt which should not produce scratches on bones but can lead to polished surfaces,” the researchers wrote in a paper published in PLOS One. A taphonomic analysis establishes the conditions under which an organism decayed or became fossilized.

The various bones retrieved from the cave were analyzed one by one and cataloged into two groups: those whose alterations were clearly made by natural processes (biological agents, weathering, fractures by large canids, rockfall etc.) and those which bear evidence of potential cultural modification.

Cut marks on the medial side, under the third and second molars, are associated with the removal of the tongue using a stone tool. Credit: PLOS One.

Cut marks on the medial side, under the third and second molars, are associated with the removal of the tongue using a stone tool. Credit: PLOS One.

For a bone modification to be identified as a cut mark — and hence evidence of ancient human presence at the Bluefish Caves — it had to fulfill all of the following criteria: shape, trajectory, number of striae, shoulder effect and shoulder flaking, internal microstriations, anatomical location and orientation.

All in all, some 36,000 mammal bones were analyzed by the Canadian researchers, mostly belonging to wolves, lions and, to a lesser degree, foxes. The researchers reckon the caves were probably used as den sites for Ursids in winter and Canids in spring and summer, while the human occupation of the caves was probably sporadic and brief.

Though biological agents and carnivore tooth marks plagued most of these samples, a total of 15 bone samples with cultural modifications confidently attributable to human activities were identified. Another two dozen bones bearing ‘probable’ alterations made by humans suggest less than 1% of the faunal remains fall into this category.

Radiocarbon dating of six cut-marked bones revealed these are between 12,000 and 24,000 years old, which is consistent with previous estimates of Bluefish Caves remains. The oldest bone is a horse mandible found buried in basal loess, at a depth of 142 cm.

“It is highly unlikely that the cut marks observed on the Bluefish Caves faunal material were generated by nonhuman agents or natural processes,” the researchers reported.

“In conclusion, while the Yana River sites indicate a human presence in Western Beringia ca. 32,000 cal BP (calibrated years Before Present), the Bluefish Caves site proves that people were in Eastern Beringia during the LGM, by at least 24,000 cal BP, thus providing long-awaited archaeological support for the “Beringian standstill hypothesis”. According to this hypothesis, a human population genetically isolated existed in Beringia from about 15,000 to 23,000 cal BP, or possibly earlier, before dispersing into North and eventually South America after the LGM,” they added.

“By around 15–14,000 cal BP an ice-free corridor formed between the Laurentide and Cordilleran ice sheets potentially allowing humans to disperse from Beringia to continental North America; arguably, this corridor wouldn’t have been biologically viable for human migration before ca. 13–12,500 cal BP, however. It is now more widely recognized that the first inhabitants of Beringia probably dispersed along a Pacific coastal route, possibly as early as ca. 16,000 cal BP, and settled south of the ice sheets before the ice-free corridor became a viable route.”

Judging from the evidence, it seems likely that the Bluefish Caves represent the oldest known archaeological site in North America, which would support the standstill hypothesis. The findings don’t contradict previous migration theories into North America. The bulk of humans going south into continental North America, then further south into Central and South America, likely started 14,000 years ago. Meanwhile, dispersed and small populations sporadically might have occupied Eastern Beringia.

Credit: The Nature Conservancy

Interactive map shows which paths animals need to take to flee climate change

Credit: The Nature Conservancy

Amphibian coded in yellow, birds in blue, and mammals in purple. Credit: The Nature Conservancy

Aside from direct human activities like logging or human activities, the biggest threat to animals’ habitats all over the world is climate change. Faced with hotter temperatures outside their comfort zones, many species of mammals, birds or amphibians find themselves forced to get the hell outta Dodge — preferably northwards or to higher elevations.

“Winter is coming!” Oh wait…

Inspired by the van Goghesque Earth wind map, which visualizes in real-time wind, temperature, and sea level pressure, Dan Majka used data from two studies to construct the paths mammals need to take to arrive in more suitable climates. In total, 2954 species had their future movements plotted by connecting current habitats with their projected locations under climate change.

The visualization is beautiful, despite its meaning lies in a saddening reality. There are reasons to be optimistic, though, as the interactive map shows many species will be able to migrate — for now. The Appalachians, one of the last pristine regions in the United States, is one of the most important funnels for this impending mass migration.

“Much of the land outside of the mountain range is developed or in agriculture,” Brad McRae, an ecologist with the Nature Conservancy, said. “So as species ranges shift north, the Appalachians are providing some of the least-developed routes for movement. They also provide some climate relief due to their high elevation.”

To make this migration as streamlined as possible, Nature Conservancy advises land managers and abled bodies to maintain or build connectivity between animal habitats. Removing fencing, constructing highway overpasses and a mindful infrastructure planning are just a couple of the things we can do.

You can study the Migrations in Motion map here.

Did the earliest Americans walk on ice or cross on water? New study sparks debate

How did people get to America, and when? A new, ‘pioneering and neat’ study may have some answers.

The traditional belief of the American migration is being challenged. Image via Wikipedia.

The traditional belief of the American migration is being challenged. Image via Wikipedia.

If we want to understand human migration, it’s all about the timings. For example, if you’d ask anthropologists how the earliest people got to the Americas, they’ll likely tell you they crossed a small land bridge between Siberia and Alaska. This would mean that they crossed it towards the end of the glacial age, but before all the ice melted and submerged the bridge. This puts a fairly good time frame on the event and it’s what most scientists believed.

But recently, that belief is starting to be challenged. There is mounting evidence that the presumed ice-free corridor on which settlers arrived wasn’t walkable until much later, when the first humans had already reached the Americas. We know that those glaciers started melting 14,000–15,000 years ago, during the time of the Clovis Culture. The Clovis people were the ones to pass through the land bridge which is now underwater, settling in the lower 48 states some 13,000 years ago. But the time doesn’t fit, because there is evidence of human activity in the Americas from 15,000 years ago. This means that someone got there before the Clovis did.

Researchers believed early settlers passed through a similar Alaskan landscape. Image via Pixabay

A new study adds a lot of weight to that idea. The research analyzed the DNA of pollen, plants, and animals collected from lake sediments around the presumed land bridge, finding that the date in which it was passable was 12,600 years ago. This is millennia after the first people got to North America.

“This is a really neat and pioneering study,” says Stephen Jackson, a paleoecologist with the U.S. Geological Survey’s Southwest Climate Science Center in Tucson, Arizona, who was not involved in the work. Because this is the first study to take into account both so-called environmental DNA (eDNA) as well as more traditional types of data, he says, “we stand to learn a good deal more about how to interpret our records.” Because DNA has an electric charge, it can bind to some sediments and preserve itself for a longer time in calm lake sediments.

The DNA of a migration

The core samples they took paint a very clear picture of an environmental transition: from icy wasteland to fertile forest to the underwater environment we see today. For the first 700 years after the ice started retreating, there were almost no plant or animal remains. Then, they found evidence of animals such as woolly mammoth, bison, and jackrabbits. By about 12,400 years ago, forests of Populus trees (related to poplar trees) started to dominate, and the area was likely a fertile forest. Then, about 11,600 years ago, it changed again, becoming a boreal forest of spruce and pine trees.

This timeline may have to be rethinked. GIF via Wikipedia.

However, settlers had already reached America by then, and Jackson believes they took the coastal route. Using the numerous islands in the area as pit stops.

“The idea is that there was a land bridge a few thousand years earlier than the formation of the ice-free corridor,” he says. “That land is now covered by ocean, but there are some islands believed to be part of that route. It would be interesting to go and look for cores and try to do the same exercise there.”

It’s not the first study to suggest this. Previously, another recent study of mitochondrial DNA in northern and southern populations of bison separated by the corridor puts the walkable date at 13,000 years ago – which might be enough for the Clovis people.

“It’s a pretty subtle difference,” says Duane Froese, a geoscientist from the University of Alberta, Edmonton, in Canada, and a co-author of that study.

However, that difference could be very significant, and not everyone is convinced. This type of paleoecology DNA study is still in its infancy, but it is a very intriguing starting point.

Journal Reference: Postglacial viability and colonization in North America’s ice-free corridor. Nature (2016) doi:10.1038/nature19085

AlpineSwift

These migrating birds fly non-stop for six months

AlpineSwift

All migrating animals, whether they do it by walking, swimming or flying, are nothing less than amazing. The intense energy expenditure most migrating species make to reach breeding grounds or safe, warm areas is absolutely amazing. Even after traveling thousands of miles away from home, animals like the freshwater salmon still know how to make their way back with pinpoint accuracy. The Alpine swift, a swallow-like bird species, is perhaps particularly impressive in its migrating pattern. This remarkable bird leaves its breeding grounds in Switzerland every winter to travel to the warmer shores of west Africa. The birds make this journey in six months, time in which they never stop flying! Actually, there’s very little evidence to suggesting how long they sleep.

Researchers had been suspecting that the Alpine swift was a remarkable migratory bird for some time, however, it was only after scientists at the Swiss Ornithological Institute and the Bern University of Applied Sciences in Burgdorf, Switzerland studied them very closely that the extent of their migratory capabilities surfaced.

Six birds were captured and fitted with a small device that logged acceleration and ambient light during the course of a year-long migration cycle that began and ended in Switzerland. Only three of them were eventually recaptured but this proved enough to reveal how the Alpine swift migrates.

Using data provided by the accelerometer, the researchers could accurately assess when the birds flapped their wings vigorously, when they glided or when they rested. The birds appeared to glide and flap throughout their entire migration across the Sahara Desert and their overwintering period in sub-Saharan West Africa. Apparently, the birds only rested their wings entirely during the breeding season in Switzerland.

“Their activity pattern reveals that they can stay airborne continuously throughout their nonbreeding period in Africa and must be able to recover while airborne,” the team writes in the report. “To date, such long-lasting locomotive activities had been reported only for animals living in the sea.”

Wait a minute? Where do these birds get all their energy – don’t they stop to eat or sleep? Whales and various migrating fish species also travel for months at a time without stopping. These swimming animals feed on the move on marine plankton. Similarly, the Alpine swifts feed mid-flight on an array of tiny bacteria, fungus, seeds, spores and small insects that get caught in air currents.

Observations show that the birds alternate between vigorous flapping and gliding when they rest. Still, the clear lack of significant resting periods suggests that the birds do not need as much sleep to perform their migration as previous research has suggested. It’s worth noting that while some marine migratory animals may swim just as long and continuously as the Alpine swift, the former have the advantage of exploiting buoyancy and thus conserve energy.

“We cannot rule out that the Alpine swifts may interrupt their flight for a few minutes,” the team writes. “Nevertheless, they must be able to accomplish all vital physiological functions in flight over a period of several months.”

I can barely perform them in bed. Well played, Alpine swifts.

The researchers detailed their findings in a paper published in the journal Nature Communications.

Challenging the “Out of Africa” theory, one tooth at a time

Recent fossils unearthed in the Chinese province of Daoxian come to unravel the story of humanity’s spread as we know it today. The find consists of 47 teeth, belonging to modern humans, but what’s really important is their age – they have been dated to 80,000 years ago. This number doesn’t fit with the “Out of Africa” migration theory, holding that humans originate and have spread from the horn of the continent all around the world. The theory as we know it can’t explain human presence in the area for another 20,000 years.

These 47 teeth, estimated to be between 80,000 and 120,000 years old, were found in a cave in Dao county, Hunan province in China.
Image via cnn

“We need to re-think our models. Maybe there was more than one Out of Africa migration” says Dr. María Martinón-Torres, UCL.

Evidence from several fields of science supports the dispersal of our species from Africa some 60,000 years ago. It is believed that a group of nomads crossed the Red Sea, by taking advantage of the Bab el Mandeb straits’ low water levels, and that from them, all non-African people today originate. But the excavations at Funyan Cave in Daoxian throw a wrench into the workings of this theory:

“It was very clear to us that these teeth belonged to modern humans [from their morphology]. What was a surprise was the date,” Dr María Martinón-Torres, from University College London (UCL), told BBC News. “All the fossils have been sealed in a calcitic floor, which is like a gravestone, sealing them off. So the teeth have to be older than that layer. Above that are stalagmites that have been dated using uranium series to 80,000 years.“

Everything under those stalagmites must be older than 80,000 years; the teeth could even be 125,000 years old, according to the researchers. Animal bones found with the teeth are also typical of the late Pleistocene, the same time period indicated by radioactive dating.

Now, these are not the first fossils of modern humans that predate the Out of Africa migration – some were found in Skhul and Qafzeh caves in Israel, for example. But due to their close proximity to the African continent, they were regarded as nothing more than a failed attempt at dispersal by groups of people who probably went extinct. But discovering modern fossils all the way in China is another thing entirely.

“Some researchers have proposed earlier dispersals in the past,” said Dr Martinón-Torres. “We really have to understand the fate of this migration. We need to find out whether it failed and they went extinct or they really did contribute to later people. Maybe we really are descendents of the dispersal 60,000 years ago – but we need to re-think our models. Maybe there was more than one Out of Africa migration.”

Professor Chris Stringer, working at London’s Natural History Museum, believes that the study will become a “game-changer” in finding out how modern humans spread around the world.

“Many workers (often including me) have argued that the early dispersal of modern humans from Africa into the Levant recorded by the fossils from Skhul and Qafzeh at about 120,000 years ago was essentially a failed dispersal which went little or no further than Israel.”

“However, the large sample of teeth from Daoxian seem unquestionably modern in their size and morphology, and they look to be well-dated by uranium-thorium methods to at least 80,000 years. At first sight this seems to be consistent with an early dispersal across southern Asia by a population resembling those known from Skhul and Qafzeh. But the Daoxian fossils resemble recent human teeth much more than they look like those from Skhul and Qafzeh, which retain more primitive traits. So either there must have been rapid evolution of the dentitions of a Skhul-Qafzeh type population in Asia by about 80,000 years, or the Daoxian teeth represent a hitherto-unsuspected early and separate dispersal of more modern-looking humans.”

Dr Pontus Skoglund, from the department of genetics at Harvard Medical School, told BBC News:

“The genetic evidence we have puts strong constraints on some aspects of human history, but less so on the timing of the out of Africa event.” Sais Dr. Pontus Skoglund. Most genetic reconstructions based on modern data relies on assumptions on the mutation rate, for which there are still some real uncertainties. In terms of direct genetic evidence, we already have a 45,000 year-old genome from Siberia (Ust Ishim) and a ~40,000 year old individual from Europe (Oase) that are consistent with being from now-mostly-extinct lineages. ”

“The conclusion is perhaps that the genetics does allow an 80,000 year old East Asian population to contribute some ancestry to present-day people, but I think not very much. It is a very interesting discovery that is hard to fit in our current thinking, but not impossible. We are just starting to cope with this data point.”

Dr Martinón-Torres said the study could also shed light on why it took Homo sapiens another 40,000 years to settle Europe. Perhaps it was Neanderthal presence that kept our species out of the western part of Eurasia, until their numbers started to dwindle; or, maybe it was the cold climate that kept us away.

Skoglund also noted that while modern humans occupied the warmer south of China 80,000 years ago, the colder regions of central and northern China appear to be settled by more primitive human groups who may have been Asian relatives of the Neanderthals.

The full study was published in the journal Nature.

Migration route

Maps that explain today’s major migration routes

Migration route

Map by National Geographic

Syrian refugees are making headlines all over the world, but while their story is worth covering, there are millions other refugees in Asia, Central America or Africa that are in the same boat. According to the U.N., 59.5 million people were displaced due to “persecution, conflict, generalized violence, or human rights violations” in 2014 or 8.3 million more than the year before. To escape persecution, refugees take hidden routes out of their own country which are often controlled by smugglers and can be extremely dangerous to cross. Everybody was heartbroken to learn about the story of three-year-old Aylan Kurdi, who was found washed ashore in Turkey, but few know that  2,900 other people died drowned or asphyxiated on their way to a safe haven this year alone. National geographic just released five great maps that explain the global forced migration patterns.

Eastern Mediterranean Route by National Geographic

Eastern Mediterranean Route by National Geographic

 

This is the most famous route news outlet choose to speak about, with the epicenter being people fleeing Syria, flocking for the EU.

“As of this week, the number of refugees fleeing the conflict in Syria approached 4.1 million. These Syrians in exile have sought shelter in camps and temporary housing in Turkey, Egypt, Iraq, Jordan, Lebanon and throughout North Africa. Almost half have landed in Turkey, according to the UN, but conditions there have been worsening.

The Eastern Mediterranean route—the passage long used by migrants crossing through Turkey to the European Union—has grown ever more crowded since the outbreak of war in Syria in 2011. Syrian routes have also been merging along easternmost points below the Mediterranean Sea of an East African migratory route that has long been used by people fleeing conflict in Somalia, the Democratic Republic of the Congo, and South Sudan.”

migrant sea route

Mediterranean Sea Route by National Geographic

 

“Nearly 90 percent of those who attempt to reach Europe by sea come from ten countries, in descending order by percentage: Syria, Afghanistan, Eritrea, Nigeria, Pakistan, Iraq, Somalia, Sudan, Gambia, and Bangladesh”

Central American Route by National Geographic

Central American Route by National Geographic

 

“Poverty and violence in Mexico and Central America has uprooted millions. Many have taken the treacherous journey north along smuggling routes, increasingly controlled by drug cartels, towards the U.S. border. The human flow includes more than 68,000 unaccompanied minors attempting to cross the border between 2013 and 2014, according the U.S. Customs and Border Protection.

Long-simmering conflict in Colombia has resulted in more than six million internally-displaced people there while  an increasingly violent drug trade in Honduras and El Salvador has fueled more destabilization in the region.”

Southeastern Asia route

Southeastern Asia route by National Geographic

 

“Political upheaval—including Muslim Rohingya refugees who have fled political repression in Myanmar—restrictive migration policies, and a lack of legal frameworks for refugees have made Southeast Asia increasingly dangerous for migrants. Human trafficking, forced labor and other abuses are also rife in the region, according to the UN.”

Innovation 101 – migratory study offers insight into how humans develop new technology and ideas

The human inovation process is more of a slow, steady climb than a sum of great leaps, a new University of Reading study shows. Our minds tend to innovate by adding small improvements through trial and error report the scientists, who studied one of the most important cultural events in human history – the migration of the Bantu-speaking farmers in Africa some 5,000 years ago. Mark Pagel, Professor of Evolutionary Biology at the University, led the study.

Image via whitecoatblacksheep

Using data about current communities and an intricate language family tree, researchers found that the Bantu tended to stick to familiar territory — literally and figuratively: they largely kept to the savannas they knew, and avoided the new and strange Congo rainforests. when they finally moved into these areas, their migration slowed down, effectively halting in the forested areas for nearly 300 years. The team argues that the primitive farmers needed this time to adapt to their new environment, and to acquire the knowledge and technology they needed to master this very different environment.

The research suggests that innovation does not come as easily to humans as we might have believed. It also faults the theory that thinking hard will lead to the right solution, and places the merit of innovation to a steady accumulation of knowledge and experience passed down from one generation tothe next.

“Sweeping out of West Central Africa more than 5,000 years ago the Bantu migration was one of the most influential cultural events of its kind. Disease, changes in climate and an increase in population meant it spread over a vast geographical area, eventually moving all the way down to the southern tip of the African continent,” Pagel said.
“But despite being modern humans with the intelligence and skills to adapt, the Bantu seemed to choose routes that kept them in familiar environments. Exploring exactly how this happened provides crucial evidence of how humans go about developing ideas and new technologies.”

The team’s efforts were focused on re-creating probable migration paths of over 400 Bantu-speaking groups. Their models showed that their incursions were followed corridors of savannas — which they were used to traversing and living off of — rather than following a more random distribution through jungle and savannah.

“Crucially, our findings fit with archaeological evidence. The research demonstrates that despite humans having an unmatched cultural potential for innovation, we perhaps underestimate how difficult developing life-changing new technologies actually is.”

The study offers some valuable insight into the way our brains work on innovation. The image of the genius is a powerful motif in our culture, evoked from comic books, with know it all Tony Stark, to giants of literature such as Sherlock Holmes. But those “Eureka” moments are not what got us down from the trees or put us on the moon. The heavy lifting was done the old fashioned way — with lots of elbow grease.

“From Watt’s steam engine design to Edison’s lightbulb, history is replete with the ‘genius’ inventor. But those amazing feats were not developed in a ‘Eureka moment’. Watt’s engine was more a redesign more than an invention. Edison’s notebook reveals that he tried thousands of filament materials before alighting by chance on his favoured material.”

“Very little has changed. Even today, science and business rely on groups pooling their knowledge and skills, and even then many groups cannot compete. Innovation is hard even for the most intelligent species on Earth.”

 

The first Americans came from Russia’s frozen expanse, Siberia, some 23,000 years ago

A new study comes to dismiss the popular idea that Native Americans draw their genetic heritage from Polynesians or European peoples.

The first humans to reach the Americas came from Siberia in a single group some 23,000 years ago, at the height of the last Ice Age, says the new study. On their way to Alaska, they hanged around in the northern regions for a few thousands of years before moving deeper into North and South America.

Presumably for that delicious, cave-made maple syrup.

Presumably for that delicious, cave-made maple syrup.

They lived in low-land, shrubby areas for an estimated 10.000 years, but archaeological evidence is hard to come by to help reach a definite number.

This map shows the outlines of modern Siberia (left) and Alaska (right) with dashed lines. The broader area in darker green (now covered by ocean) represents the Bering land bridge near the end of the last glacial maximum, a period that lasted from 28,000 to 18,000 years ago when sea levels were low and ice sheets extended south into what is now the northern part of the lower 48 states. University of Utah anthropologist Dennis O’Rourke argues in the Feb. 28 issue of the journal Science that the ancestors of Native Americans migrated from Asia onto the Bering land bridge or “Beringia” some 25,000 years ago and spent 10,000 years there until they began moving into the Americas 15,000 years ago as the ice sheets melted.
Credit: Wlliam Manley, Institute of Arctic and Alpine Research, University of Colorado.

They settled on a land bridge that connected Eurasia to the Americas, named Beringia. The ice sheets extended south into the Pacific Northwest, Wyoming, Wisconsin and Ohio. Large expanses of Siberia and Beringia were cold but lacked glaciers. As the planet warmed up however, ice melted, sea levels rose the area got slowly flooded, creating what we today know as the Bering Strait. These early settlers were forced to relocate and some of them found their way to America, but their settlements, and any traces of their daily lives were lost under the waters.

The lack of archaeological evidence makes precisely dating these events very tricky, but scientists are confident that genetic sequencing can help us with that:

“There is some uncertainty in the dates of the migration and the divergence between the northern and southern Amerindian populations. But as we get more ancient genomes sequenced, we will be able to put more precise dates on the times of migration,” said one of the study authors Yun Song, associate professor at University of California, Berkeley.

The analysis, using the most comprehensive genetic data set from Native Americans to date, was conducted using three different statistical models. The data consisted of the sequenced genomes of 31 living Native Americans, Siberians and people from around the Pacific Ocean, and the genomes of 23 ancient individuals from North and South America, spanning a time between 200 and 6,000 years ago.

The international team concluded that the northern and southern Native American populations diverged between 11,500 and 14,500 years ago.

The southern branch peopled Central and South America as well as part of northern North America. The findings will be presented in the forthcoming issue of the journal Science.

“The diversification of modern Native Americans appears to have started around 13,000 years ago when the first unique Native American culture appears in the archaeological record: the Clovis culture,” said Rasmus Nielsen, a professor at the California university. “We can date this split so precisely in part because we previously have analysed the 12,600-year-old remains of a boy associated with the Clovis culture,” Nielsen added.

Isotopes inside salmon ear tell a fishy story

According to a new study, just like tree rings carry with them hints about previous dry or rainy years, bones in fish carry with them a specific signature which records the chemical composition of the waters they used to live in.

A cross-section of a salmon otolith, also known as a fish ear stone or fish ear bone. Scientists measured Strontium ratios and identified the waters in which the fish lived for its entire life. The new fish-tracking method may help pinpoint critical habitats for fish threatened by climate change, industrial development and overfishing. Credit: Sean Brennan, University of Washington
Read more at: http://phys.org/news/2015-05-chemical-tags-ear-bones-track.html#jCp

Most vertebrates, especially fish, have what is called an ‘otolith’ – a specific bony structure inside the inner ear. The  otolith accretes layers of calcium carbonate and gelatinous matrix throughout the entire life. The accretion rate varies with growth of the fish – often less growth in winter and more in summer – which results in the appearance of rings that resemble tree rings; and just like with tree rings, scientists can figure out the age. Another interesting fact is that the otolith isn’t really digestible, so it often remains stuck in the digestive tract of fish-eating animals, and scientists can therefore reconstruct their eating habits.

But whenever the otolith grows and accretes more calcium carbonate, it also traps in other elements – extremely small fractions of the chemical makeup of the waters in which the fish live in. Specifically, it traps in specific isotopes, in specific quantities; by analyzing these isotopes, researchers are now able to reconstruct where the fish was born and where it traveled for its entire life.

Sean Brennan from the University of Washington and lead author explains:

“Each fish has this little recorder, and we can reveal the whole life history of the fish from the perspective of the otolith. Each growth ring is a direct reflection of the environment the fish was swimming in at the time it was formed.” Brennan completed the study as a doctoral student at the University of Alaska Fairbanks. He is now a postdoctoral researcher in the University of Washington’s School of Aquatic and Fishery Sciences.

Specifically, they looked at the trace element strontium. Strontium is a very reliable element for this type of reconstructions because it almost never alters and strontium levels vary greatly depending on the age and structure of the bedrock. In other words, by looking at how the strontium in an area looks like you can figure out (to some extent) where it comes from. But it wasn’t an easy feat. Thure Cerling, also an author, explains:

“There are literally thousands of measurements on each otolith,” Cerling says.

Geochemist Diego Fernandez further adds:

“They’re like microexplosions. You create tiny, tiny particles that are carried into the mass spectrometer.” By showing how the ratio of strontium-87 to strontium-86 changed over time, “we get the entire life history of the salmon,” he says.

Some areas more than others are better candidates for this type of analysis, but researchers wanted a challenge – so they chose Alaska.

“Alaska is a mosaic of geologic heterogeneity,” he added. “As long as you can look at a geologic map and see rocks that are really different, that’s a good potential area.”

One of the many tributaries to the Upper Nushagak River. Credit: Sean Brennan, U of Washington

About 200,000 Chinook salmons make their way to the breeding grounds in Bristol Bay every year. When the eggs hatch in the spring, the little salmons spend a whole year in the river before venturing to the Bering Sea, and ultimately, the Pacific Ocean.

This is not only an extremely exciting find, but one that can have a great effect on fish populations throughout the world. By analyzing several otoliths, scientists can now see if their migratory patterns have remained similar, or if they have changed – likely due to some stress. From a conservation standpoint, that’s a game changer.

“This is science responding to a societal issue and need,” said co-author Christian Zimmerman, U.S. Geological Survey ecologist and chief of water and interdisciplinary studies at the USGS Alaska Science Center in Anchorage. “Using this approach, we will be able to map salmon productivity and determine how freshwater habitats influence the ultimate number of salmon. With declines in Chinook salmon in Western Alaska, fishery and land-use managers need better information about freshwater habitats to guide conservation.”

But it’s not just fish – the same technique could be used for other animals. Strontium is known to accumulate in bird feathers and teeth and also survives even after being fossilized. It could help us understand moving patterns better than ever.

Journal Reference: Sean R. Brennan, Christian E. Zimmerman, Diego P. Fernandez, Thure E. Cerling, Megan V. McPhee, Matthew J. Wooller. Strontium isotopes delineate fine-scale natal origins and migration histories of Pacific salmon. DOI: 10.1126/sciadv.1400124

The blackpoll warbler (Setophaga striata) in fall plumage. Image: Wikimedia Commons

Awesome tiny birds cross the Atlantic in one go without stopping

More than half a century in question, scientists now confirm that the tiny  blackpoll warbler flies nonstop over the North Atlantic Ocean each autumn from New England to South America. The trip takes three days, during which the bird foregoes any rest, sleep or meal. It also absorbs its own intestines.

The blackpoll warbler (Setophaga striata) in fall plumage. Image: Wikimedia Commons

The blackpoll warbler (Setophaga striata) in fall plumage. Image: Wikimedia Commons

Researchers have suspected for almost 50 years that the bird, which tips the scale at only half an ounce (three teaspoons of sugar), makes this epic journey without stopping, judging from radar data or sightings of the birds on ships in the Atlantic. But there’s always uncertainty when dealing with a 1,500 long-journey and such a small bird. The mystery was finally solved by a group of ecologists who placed geolocators on 40 birds to uncover their overwater route. The devices showed that the birds flying from their summer homes in Vermont and Nova Scotia flew between 1,410-1,721 miles until they reached Puerto Rico, Cuba and the Greater Antilles islands. This was their stop before continuing to their autumn lodging in northern Venezuela and Colombia, are ported in Biology Letters.

One of the birds with a geolocator. These were retrieved after the bird took arrived at its destination. CREDIT: VERMONT CENTER FOR ECOSTUDIES

One of the birds with a geolocator. These were retrieved after the bird took arrived at its destination. CREDIT: VERMONT CENTER FOR ECOSTUDIES

Now ultra-long flights aren’t unheard of. Albatrosses, sandpipers and gulls are famous in this respect, but what sets the blackpoll warbler apart is its size. Where does such a tiny thing gets all of its energy? For one, the birds excellently time their flights to correspond with wind patterns. To survive, however, the bird also undergoes physiologically changes. According to Bill Deluca, an ecologist at the University of Massachusetts, Amherst, the birds fatten up before their trip, growing to roughly 0.6 ounces, from 0.4. Some birds grow to 0.8. “Basically, they’re these little meatballs with wings,” he says. Then, the birds absorb the internal organs they don’t need for the trip, like the intestines, to reduce load and free energy.

“For small songbirds, we are only just now beginning to understand the migratory routes that connect temperate breeding grounds to tropical wintering areas,” said Bill DeLuca at the University of Massachusetts Amherst.

“We’re really excited to report that this is one of the longest non-stop overwater flights ever recorded for a songbird, and finally confirms what has long been believed to be one of the most extraordinary migratory feats on the planet.”

The researchers were less interested in solving a Guiness Book mystery than they were intend on tracing the decline of blackpoll populations. The songbirds are among the most common and can be found throughout North America, yet they’ve greatly declines in numbers in recent years. Researchers aren’t sure why, but these tracking efforts serve to guide them. For instance, it could help establish whether there’s a problem in North America or South America. It could very well be something on the return-trip, which goes on an alternate route. The return flight home is made over land, not over water. This more dangerous since they encounter more predators or man-made perils like high speed cars. Scientists aren’t sure why the return trip isn’t made overseas, but it might the remnant of an ancient migratory path.