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Top 10 deadliest volcanic eruptions

Thu, 2014-08-07 14:02
Volcanoes are among the most devastating and dangerous natural forces in our past, but it is not just throughout history that they wreaked havoc on human life but right up to the 21st century. Their volatility and unreliability have changed our world’s landscape over time and also lives of the people living in their shadows. Here are listed the 10 most deadly recorded volcanic eruptions.


10 Mt. Galunggung, Java Indonesia

Date: 1882

Death toll: 4,011

Galunggung Crater: Wikimedia

The Volcano erupted in October in 1882. As well as killing 4,011 people the eruption also destroyed 114 villages. Mt Galunggung is located on the Pacific Ring of Fire, a well-known collection of volcanoes along a horseshoe shape around the coasts of Asia and the west coasts of Central and South America. This particular eruption was a VEI (Volcanic Explosive Index) 5 volcanic eruption.


9 Mt. Kelut, Indonesia

Date: May 19th, 1919

Death toll: 5,110

Kelut Eruption: WikiPedia

When Mt. Kelut erupted in 1919 over 100 villages were destroyed due to lethal lahars that traveled a distance for 40 kilometers. During this eruption 38 million cubic meters of water were ejected from the crater lake. The volcano has erupted on a large scale several times since 1919, including once in 1966 and again in 1990.


8 Mt, Vesuvius, Italy

Date: 1631

Death toll: 6,000

Mount Vesuvius: Wikimedia

Since the famous eruption of 79 AD Mt. Vesuvius has erupted more than a dozen times. The Volcano unexpectedly erupted between the hours of 6 and 7am on 16th December 1631. During this eruption the surrounding area suffered from multiple earthquakes, large ash clouds, showers of rock and pumice and a river of lava flowing from the conical crater of the volcano. The eruption lasted several days and it was not until 19th December that rescue efforts were able to commence.


7 The Laki Volcanic System, Iceland

Date: June 8th 1783- 8th February 1784

Death toll: 9,350

Laki Volcanic System: WikiPedia

This eruption lasted a whopping eight months spewing a total of 14.7 cubic kilometers of lava and 27km of fissures. Despite the extremely high volume of volcanic material that was expelled from the volcano during this eruption, this was not the primary cause of the large death toll. It was in fact the deadly gas emission that was the killer. Large quantities of gas were released into the atmosphere consisting of water vapor, carbon dioxide, sulphur dioxide, hydrogen chloride and flouride. This ultimately created a cloud that remained over Iceland and proceeded to create acid rain, poisoning livestock and the soil.


6 Mt.Vesuvius, Italy

Date: August 24th AD 79

Death toll: 10,000+

Artist representation of Mount Vesuvius: WikiPedia

This is possibly one of the most famous volcanic eruptions in history and it is particularly infamous due to the burial of two Italian towns, Herculaneum and Pompeii. This eruption is so well documented due to the eyewitness account of Pliny the Younger. During this eruption Mt. Vesuvius expelled a deadly cloud of volcanic gas, stones, ash and fumes that rose to a tremendous height of 33km. The eruption lasted two days and the eruption was made even more tragic because of the fact that the unsuspecting residents of the Bay of Naples were unaware that they were living in the shadow of a deadly volcano.


5 Mt.Unzen, Japan

Date: 1792

Death toll: 12,000-15,000

Mount Unzen: WikiPedia

The eruption of Mt. Unzen in 1792 is the most catastrophic and deadly in all of Japan’s history. The initial eruption triggered a landslide and tsunami. Mt. Unzen consists of a group of composite volcanoes and they are located east of Nagasaki. It is said that most of the death toll was as a result of the landslide and tsunami; evidence of the devastating landslide can still be seen today.


4 Nevado del Ruiz, Columbia

Date: November 13th, 1985

Death toll: 23,000

Nevado del Ruiz: WikiPedia

Despite being considered a medium sized eruption the volcanic event still had devastating consequences for the surrounding regions. The eruption commenced in the night and caused both cold and hot mudflows, which buried the town of Armero. After the eruption there were intense debates about responsibility as there were signs of an upcoming eruption including earthquakes. The Columbian government consequently created a program to prevent incidents of this nature in the future.


3 Mt. Krakatoa, Indonesia

Date: August 16th-28th 1883

Death toll: 36,000

Mount Krakatoa: Wikimedia

Due to this eruption a massive two thirds of Krakatoa actually collapsed, destroying a large proportion of the island. There were significant effects felt across the world, the sound of the explosion was so loud that it was heard in Australia and spectacular sunsets were experienced around the globe for months following the eruption.


2 Mt. Pelee, West Indies

Date: April 25th-May 8th, 1902

Death toll: 40,000

Mount Pelée: WikiPedia

At the time of the eruption the volcano was thought to be dormant but a series of eruptions began in April 25th 1902, resulting in the final eruption on May 8th 1902. This final eruption was so destructive that is destroyed the city of St. Pierre. There were only two survivors.


1 Mt. Tambora, Indonesia

Date: April 10th -15th, 1816

Death toll: 92,000

Mount Tambora: WikiPedia

As a result of this eruption the once tall volcano that stood at 13,000 feet was reduced to 9,000 feet. Also due to the destructive eruption, 1816 became known as the “year without summer” because the ash in the atmosphere reduced the temperature, this was felt worldwide, not just in Indonesia. Interestingly, it is thought that an additional 100,000 people may have died from crop failures as far as Europe and America due to the reduction in temperatures as a direct result of the eruption.




Header Image Source: Fotopedia

Categories: General

10 must see historic walls

Thu, 2014-08-07 13:45
The world has seen many wars and conflicts throughout history, which has given us a multitude of ancient defensive structures, like fortified walls, to see and explore. Here listed are just some of the many historic walls that litter the earth. They are all impressive feats of architecture for their time of construction and boast the pride and strength of their ancient civilizations.


1 Great Wall of China

The Great Wall of China is possibly the most famous fortification on the globe. It is constructed of various materials including: stone, brick, tampered earth and wood.

Great Wall of China: WikiPedia

The wall stretches east-to-west along the northern borders of China as protection for the Chinese Empire. The wall dates back as far as the 7th century BC and has undergone various maintenance works since.


2 Hadrian’s Wall

Hadrian’s Wall is located in northern England and was constructed under the rule of emperor Hadrian in AD 122.

Hadrian’s Wall: WikiPedia

A large proportion of the wall still exists today and many Roman enthusiasts embark upon a pilgrimage yearly to walk along the wall.


3 Antonine Wall

The construction of the wall began in 142 AD and took a total of twelve years to be completed. The wall resides on the border of Scotland, on what was the British Roman Empire’s northernmost border.

Antonine Wall: WikiPedia

The wall contained 16 forts and was approximately 63 kilometers long and 3 meters high. Today not many of the fortifications survive but some of the remains are still visible.


4 Walls of Troy

Located in what is now Turkey, the Walls of Troy are some of the oldest walls that survive today. It is believed they date as far back as the 13th century BC.

Walls of Troy: WikiPedia

The walls were constructed as protection for the legendary city of Troy and they survived the famous 10-year siege.


5 Aurelian Walls

The Aurelian Walls are located in Rome, Italy and were constructed during the rein of the Roman Emperors Aurelian and Probus between 271 AD and 275 AD.

Aurelian Walls: Wikimedia

The Aurelian Walls are famous for being the longest and best-preserved ancient city walls that survive in the world today. They are over 11 miles in total length.


6 Walls of Constantinople

The Walls of Constantinople defended and surrounded the city of Constantinople, now known as Istanbul, Turkey.

Walls of Constantinople: WikiPedia

Constantine the Great built the walls and due to various alterations over time they became one of the most elaborate wall systems ever built.


7 Caerwent

Caerwent is located is South Wales and is home to some of the best preserved Roman ruins, including the mile-long wall that still stands today.

Caerwent, the south walls: Wikimedia

The walls date back to approximately to the 2nd century AD and they once reached an impressive 25 feet. The south wall is best preserved of the surviving walls and is well worth a visit.


8 The Walls of Ston

Located in Croatia the walls were built in the 15th century and are 5.5km long.

The Walls of Ston: Wikimedia

The defensive structure originally contained 40 towers and 5 fortresses. The walls are famous for being the second largest in Europe.


9 The Walls of Babylon

The Walls of Babylon date back to 575 BC and are situated approximately 85km south of Baghdad, Iraq.

Walls of Babylon: Wikimedia

Because of the grandness of its architecture the Walls of Babylon were considered one of the wonders of the ancient world.


10 Sacsayhuaman

Sacsayhuaman is a walled complex located on the outskirts of the city of Cusco in Peru.

Sacsayhuaman: Wikimedia

Cusco was the formal capital of the ancient Inca Empire and the wall structure is comprised of large polished dry stonewalls with boulders cut in. The wall reaches a massive height of 3,701 meters and was made a UNESCO World Heritage site in 1983, along with the city of Cusco itself.



Header Image Source: WikiPedia



Categories: General

10 Historical Houses

Wed, 2014-08-06 14:32
The world is full of fascinating historic houses that are begging to be explored. By visiting them you can obtain a wealth of information about the people who once lived there and what shaped their lives. From the haunted mansions, to the quaint birthplaces of historical figures, here is a list of just some historical houses that are currently still standing in the world today.


Stone House in Nas montanhas de Fafe

This stone house is located in Nas montanhas de Fafe in Portugal.

Stone house in Nas montanhas de Fafe: Wikimedia

Like most 21st century houses, the house has windows and doors but it is constructed completely of stone. It also has a significant likeness to the house of the Flintstone family from the popular cartoon of the 1960s. It appears to be a stone house, set between two boulders and looks like how popular culture would imagine a stone-age house.


Hanging Houses of Cuenca

Also known as The Casas Colgadas (literally meaning Hanging Houses) the complex of hanging houses resides in the Cuenca region of Spain.

Hanging houses of Cuenca: Wikimedia

It is unclear as to when theses houses were first constructed, but evidence has been found of their existence in the 15th century. Currently only a few of the houses still stand.


Kingston Bagpuize House

Kingston Bagpuize House is a 17th century manor house located in the village Kingston Bagpuize, west of Abingdon.

Kingston Bagpuize House: Geograph.org

The house underwent renovations in the early 1770s and boasts marvelous grounds containing rare trees, shrubs and an 18th century paneled pavilion.


Anne Hathaway’s Cottage

Anne Hathaway was the wife of the most famous playwright of all time, William Shakespeare, and her childhood home is located in Shottery, Warwickshire.

Anna Hathaway’s Cottage: Wikimedia

The house is a twelve-room farmhouse and stands surrounded by 90 acres of gardens. The oldest part of the building was constructed in the 15th century and looks like a typical English Tudor house. There have even been replicas of the house built across the world including Australia, Canada and Texas.


The Witch House (aka The Jonathan Corwin House)

The Witch House was built in 1675 and was the home of the famous Witch Trial judge Jonathan Corwin.

The Witch House: Panoramio

Located in Salem, Massachusetts, it is the only historical building that still survives from the year 1692. It may come as no surprise that the building is said to be haunted.


Werribee Park Mansion

Werribee Park Mansion resides to the West of Melbourne and was built in the 19th century.

Werribee Park Mansion: Flickr

The wealthy sheep farmers, Thomas and Andrew Chirnside, built the house. They built the house in an Italianate-style and the interior is styled from the Victorian period.


Gainsborough Old Hall

Located in Gainsborough, Lincolnshire, Gainsborough Old Hall is one of the best-preserved manor houses to survive from England’s medieval period.

Gainsborough Old Hall: Wikimedia

The house dates back over five hundred years ago as Sir Thomas Burgh built it in 1460. The house is now owned by English Heritage and is open to the public.


Osborne House

Osborne House resides in East Cowes on the Isle of Wight, which is an island situated just off the south coast of England.

Osborne House: Wikimedia

The house was built in the late 19th century and acted as a royal residence for Queen Victoria and Prince Albert. It is actually the place in which Queen Victoria died in 1901. The house is now owned by the state and is open to the public as a museum dedicated to the memory of the popular queen.


Castle Ward

Castle Ward is an 18th century Gothic house situated in County Down, Northern Ireland and overlooks the majestic Stangford Lough.

Castle Ward House: WikiPedia

The house is surrounded by 820 acres of landscaped gardens and is home to a wealth of Victorian architecture, including a working corn mill.


Longleat House

Longleat House is a stately home that is situated near Warminster, England and was built by Sir Thomas Thynne after the priory was destroyed in a fire in 1567.

Longleat House: WikiPedia

The house if famous for being a prime example of Elizabethan architecture. It is also a very popular tourist attraction due to its vast grounds including a safari park, maze and landscaped parkland.



Header Image Source: WikiPedia


Categories: General

Scientists to explore how insects evolved ultrasonic hearing abilities over millennia

Wed, 2014-08-06 09:59
The Leverhulme Trust has awarded a grant of £250,000 to a team of scientists led by the University of Lincoln, UK, to research how a group of insects evolved incredible ultrasonic hearing abilities.

A cochlear organ for frequency selectivity was thought to be unique to the hearing of mammals until a similar mechanism for frequency analysis was discovered in the ears of bushcrickets in South American rainforests two years ago.

Scientists are under the impression that the discovery of this previously unidentified hearing organ be the beginning of a path leading to technological advancements in bio-inspired acoustic sensors, including hearing aids and medical imaging devices.

The new research project, funded by the Leverhulme Trust, has the aim to develop a deeper understanding of the evolution of ultrasonic hearing in bushcrickets, specifically how they developed the cochlear-like systems in response to changing evolutionary pressures over millions of years.

Project leader Dr Fernando Montealegre-Z, of the School of Life Sciences, University of Lincoln, UK, led the team who discovered the mysterious hearing organ in bushcrickets.

He explained, We will study these hearing systems and their variation in many species of bushcrickets. There are around 7,000 living species of these insects, but what we know about cochlear mechanisms has been investigated in only two or three. Therefore we expect to find enormous amount of variation across species. Through data from fossils and existing species, we aim to unveil major changes in sensory ecological niches and in the auditory ecology of species which have evolved from a single ancestral species.”

Bushcrickets are among the first terrestrial animals to have evolved acoustic communication. The sound that is emitted from crickets is produced by the stridulatory organ, which is a large vein running along the bottom of one wing covered in “teeth”, which is rubbed against a plectrum on the other wing. The ears, located on the cricket’s forelegs, are used in mating and predator avoidance.

Bushcricket: Flickr

Almost 70 per cent of the living species, measured with ultrasound-sensitive equipment, produce acoustic signals in the ultrasonic range. However, their ancestors communicated at much lower frequencies. Modern bushcrickets emerged about 55-60 million years ago. Since bats emerged at around the same time, the group think that bushcrickets possibly evolved ultrasonic communication and elaborate hearing mechanisms in response to acoustic predators, such as echolocating bats.

For the first time, the group will reconstruct changes in both shape and function of fossil bushcrickets’ auditory and stridulatory organs throughout the recorded history of this group, from the Triassic onwards. This allows them to obtain a greater understanding of the selective pressures that forced the evolution of cochlear systems in mammals and insects.

The work will allow the reconstruction of a series of biophysical models that will stimulate and predict tympanal vibrations and wing resonances in extinct bushcrickets, as well as the acoustic reconstruction of the bushcricket community that lived in the long-gone forests of the Triassic and Jurassic eras.

Dr Montealegre-Z said, “Findings will help to comprehend the multiple origins and diversity of auditory mechanisms in mammals and insects. Results will also open up our understanding of the acoustic ecology of extinct environments where other auditory animals lived, and not only provide insights into the lives of singing insects, but that of their prey and predators. Studying fossil insects advances our general understanding of both behavioral and physical ecologies of the forests of the distant past.

“The research encompasses several disciplines including paleontology, biophysics, physiology and engineering. The integration of these disciplines is original and innovative and will open up new opportunities to enhance the current knowledge of sensory mechanisms in living organisms, including humans.”



Contributing Source: University of Lincoln

Header Image Source: WikiPedia


Categories: General

Flores bones show features of Down syndrome, not a new ‘hobbit’ human

Tue, 2014-08-05 10:25
In October 2004, the excavation of the fragmentary skeletal remains from the island of Flores, located in Indonesia, yielded what was deemed “the most important find in human evolution for 100 years.” The exciting discoveries dubbed the find Homo floresiensis, a name implying a previously unknown species of our evolutionary past.

A detailed reanalysis by an international team of researchers including Robert B. Eckhardt, professor of developmental genetics and evolution at Penn State, Maciej Henneberg, professor of anatomy and pathology at the University of Adelaide, and Kenneth Hsü, a Chinese geologist and paleoclimatologist, implies that the single specimen which sparked the new designation, known as LB1, actually does not represent a new species. Instead, it is the skeleton of a developmentally abnormal human and, according to the research team, contains important features that are most consistent with the diagnosis of Down syndrome.

“The skeletal sample from Liang Bua cave contains fragmentary remains of several individuals,” Eckhardt said. “LB1 has the only skull and thigh bones in the entire sample.”

No significant new bone discoveries have been made in the cave since the unearthing of LB1.

Initial descriptions of Homo floresiensis focused on LB1’s unusual anatomical characteristics: a cranial volume reported to be only 380 milliliters (23.2 cubic inches), suggesting a brain size of less than a third of an average modern human’s and short thigh bones, which were used to reconstruct a creature standing 1.06 meters (approximately 3.5 feet tall). Despite the fact that LB1 lived only 15,000 years ago, comparisons were made to earlier hominins, including Homo erectus and Australopithecus. Other traits were characterized as unique and therefore an indication of a newly discovered species.

A thorough reexamination of the available evidence in the context of clinical studies, the researchers said, suggests a different explanation.

The researchers report their findings in two papers published on August 4th, 2014, in the Proceedings of the National Academy of Sciences.

Firstly, they write, the original figures concerning the cranial volume and stature are underestimates, “markedly lower than any later attempts to confirm them.” Eckhardt, Henneberg, and other researchers have consistently found a cranial volume of about 430 milliliters (26.2 cubic inches).

“The difference is significant, and the revised figure falls in the range predicted for a modern human with Down syndrome from the same geographic region,” Eckhardt said.

The original estimate for the creature’s height at 3.5 feet was based on the extrapolation combining the short thigh bone with a formula derived from an African pygmy population. However, humans with Down syndrome also have diagnostically short thigh bones, Eckhardt said.

Though these, among other features are unusual, he acknowledged, “The difference is significant, and the revised figure falls in the range predicted for a modern human with Down syndrome from the same geographic region,” Eckhardt said.

As a result, the researchers build the case for an alternative diagnosis: that of Down syndrome, one of the most commonly occurring developmental disorders in today’s humans.

“When we first saw these bones, several of us immediately spotted a developmental disturbance,” said Eckhardt, “but we did not assign a specific diagnosis because the bones were so fragmentary. Over the years, several lines of evidence have converged on Down syndrome.

The first indicator of Down syndrome is craniofacial asymmetry, a left-right mismatch of the skull that is characteristic of this particular disorder and various others. Eckhardt and colleagues noted that this asymmetry in LB1 back in 2006, but it had not been reported by the excavating team and was dismissed as a result of the skull’s being long buried, he said.

Homo floresiensis: Fotopedia

A previously unpublished measurement of LB1’s occipital-frontal circumference – the circumference of the skull taken roughly above the tops of the ears – enabled the researchers to compare LB1 clinical data routinely collected on patients with developmental disorders. Here too, the brain size they estimate is within the range expected for an Australomelanesian human with Down syndrome.

LB1’s short thigh bones not only match the standard height reduction seen in Down syndrome humans, Eckhardt said, but when corrected statistically for normal growth, they would yield a height of approximately 1.26 meters, or just over four feet, a figure matched by some humans now residing on Flores and the surrounding regions.

These, among other Down syndrome-like characteristics, the researchers state, are present in LB1 alone, and not in the other Liang Bua skeletal remains, which is further evidence of LB1’s abnormality.

“This work is not presented in the form of a fanciful story, but to test a hypothesis: Are the skeletons from Liang Bua cave sufficiently unusual to require invention of a new human species?” Eckhardt said.

“This work is not presented in the form of a fanciful story, but to test a hypothesis: Are the skeletons from Liang Bua cave sufficiently unusual to require invention of a new human species?” Eckhardt said.


Contributing Source: Penn State

Header Image Source: WikiPedia

Categories: General

WSU researchers see violent era in ancient southwest

Mon, 2014-08-04 14:48
It’s a given, in terms of numbers, the 20th Century was the most violent in history, with the American Civil War, purges and the two World Wars killing as many as 200 million people.

However, on a per-capita basis, archaeologist Tim Kohler, from Washington State University, has documented a particularly bloody period of history more than eight centuries ago on what is now American soil. Between 1140 and 1180, in the central Mesa Verde of southwest Colorado, four relatively peaceful centuries of pueblo living devolved into several decades of incredible violence.

Writing in the journal American Antiquity, Kohler and his colleagues at WSU and the University of Colorado-Boulder document how almost nine out of ten sets of human remains from that period of history had trauma from blows either to their heads of various parts of their arms.

“If we’re identifying that much trauma, many were dying a violent death,” said Kohler, whose study was funded by the National Science Foundation.

However, in the same time period, in the northern Rio Grande region of what is now New Mexico, people suffered far less violence while still experiencing similar growth and, ostensibly, population pressures. Viewed together, said Kohler, the two areas unveil a view into what motivates violence in some societies but not others. The study also offers more information about the mysterious depopulation of the northern Southwest, from a population of around 40,000 people in the mid 1200s to none just 30 years later.

From the days they first arrived in the Southwest in the 1800s, anthropologists and archaeologists have mostly downplayed evidence of a violent conflict between the early farmers in the region. A small number raised the specter of violence but lacked a good measure for it.

“Archaeologists with one or two exceptions have not tried to develop an objective metric of levels of violence through time,” said Kohler. “They’ve looked at a mix of various things like burned structures, defensive site locations and so forth, but it’s very difficult to distill an estimate of levels of violence from such things. We’ve concentrated on one thing, and that is trauma, especially to the head and portions of the arms. That’s allowed us to look at levels of violence through time in a comparative way.”

Meanwhile, Kohler and his colleagues are studying the role of factors like maize production, alteration in the climate, and growing population in changing levels of violence. Kohler’s paper published in June in The Proceedings of the National Academy of Sciences found that the Southwest experienced a baby boom between 500 and 1300 that likely exceeded any population increase on earth today.

Both in the central Mesa Verde and northern Rio Grande experienced baby booms, said Kohler, but the unusual result is that the central Mesa Verde grew more violent while the northern Rio Grande became less violent.

Kohler offers some explanations.

Social structures among people in the northern Rio Grande altered so that they identified less with their kin and more with the larger pueblo and specific organizations that span many pueblos, such as medicine societies. In addition to this, the Rio Grande had more commercial exchanges where craft specialists provided people both in the pueblo, and outsiders, with specific things they needed, such as obsidian arrow points.

However, in the central Mesa Verde, there was less specialization.

Mesa Verde National Park: WikiPedia

When you don’t have specialization in societies, there’s a sense in which everybody is a competitor because everybody is doing the same thing,” said Kohler. But with specialization, people are much more dependent with one another and therefore more reluctant to do harm.

Kohler and his colleagues also cite Harvard psychologist Steven Pinker’s thinking in his book, The Better Angels of Our Nature: Why Violence has Declined.

“Pinker thought that what he called ‘gentle commerce’ was very important in the pacification of the world over the last 5,000 years,” said Kohler. “That seems to work pretty well in our record as well.”

The episode of conflict in Southwest Colorado appears to have begun when the people in the Chaco culture, halfway between central Mesa Verde and northern Rio Grande, attempted to spread into Southwest Colorado.

“They were resisted,” Kohler said, “but resistance was futile.”

From 1080 to 1140, the Chaco-influenced people did well. However, in the mid-1100s, there was a severe drought and the core of the Chaco culture fell apart. A large portion of the area surrounding Chaco lost population, and in 1160, violence in the central Mesa Verde peaked. Slightly more than a century later, the area was deserted.

“In the Mesa Verde there could be a haves-versus-have-nots dynamic towards the very end,” said Kohler. “The people who stayed the longest were probably the people who were located in the very best spots. But those pueblos too were likely losing population. And it might have been the older folks who stuck around, who weren’t so anxious to move as the young folks who thought, ‘We could make a better living elsewhere.’” Older, or with too few people to marshal a good defense, the remaining people in the Mesa Verde pueblos were particularly vulnerable to raids.

At least two of the last-surviving large pueblos in the central Mesa Verde were attacked as the region was being abandoned. Some of their inhabitants most probably escaped with their lives, but, says Kohler, “Many did not.”


Contributing Source: Washington State University

Header Image Source: WikiPedia


Categories: General

Society bloomed with gentler personalities and more feminine faces

Mon, 2014-08-04 09:44
Technology boom 50,000 years ago is associated with apparent reduction in testosterone.

Modern humans first appeared in the fossil record approximately 200,000 years ago, however it was only approximately 50,000 years ago that creating art and the construction of advanced tools became widespread.

A new study appearing August 1st 2014 in the journal Current Anthropology finds that human skulls altered in ways that are indicative of lowering testosterone levels at around the same time that culture began to blossom.

“The modern human behaviors of technological innovation, making art and rapid cultural exchange probably came at the same time that we developed a more cooperative temperament,” said lead author Robert Cieri, a biology graduate student from the University of Utah who began his work as a senior at Duke University.

The study is based on the measurements of more than 1,400 ancient and modern skulls and instigates the argument that human society advanced when people began being nicer to each other. This suggests having a little less testosterone was in action.

Heavy brows were filtered out, rounder heads were filtered in, and those changes can be linked directly to testosterone levels acting on the skeleton, according to Duke’s anthropologist Steven Churchill, Cleri’s supervisor on his work on a senior honors thesis that expanded to become the 24-page journal article three years later.

What cannot be distinguished from the bones is whether these humans had less testosterone in circulation, or fewer receptors for the hormone.

Sapeins and Neanderthal comparison: Wikimedia

The research team also included Duke animal cognition researchers Brian Hare and Jingzhi Tan, who state that the argument presented is in line with what has already been established with non-human species.

In a study of Siberian foxes, animals that were less wary and less aggressive towards humans were of a more juvenile appearance and behavior after several generations of selective breeding.

“If we’re seeing a process that leads to these changes in other animals, it might help explain who we are and how we got to be this way,” said Hare, who also studies the differences between our close ape relatives- the aggressive chimpanzees and mellow bonobos.

These two apes develop very differently, said Hare, as they respond to social stress differently. Chimpanzee males experience a rise in testosterone during puberty, whereas bonobos do not. When stressed, the bonobos do not produce more testosterone, but they do produce more cortisol, which is known to be the stress hormone.

Their social interactions are profoundly different and in relation to this study, their faces are different also. “It’s very hard to find a brow-ridge in a bonobo,” Hare said.

Cieri compared the brow ridge, facial shape and interior volume of 13 modern human skulls older than 80,000 years, 41 skulls from 10,000 to 38,000 years ago, and a global sample of 1,367 20th century skulls from 30 different ethnic populations.

The trend that was revealed was toward a reduction in the brow ridge and a shortening of the upper face, traits that usually reflect a reduction in the action of testosterone.

There are many theories about why, after 150,000 years of existence, humans very suddenly leapt forward in technology. Around 50,000 years ago, there is widespread evidence of the production of bone and antler tools, heat-treated and flaked flint, projectile weapons, grindstones, fishing and birding equipment and the command of fire. The question is; was this driven by a brain mutation, cooked foods, the advent of language, or simply population density?

The Duke study implies that living and cooperating together put a price on agreeableness and lowered aggression and that, in turn, lead to changed faces and more cultural exchange.

“If prehistoric people began living closer together and passing down new technologies, they’d have to be tolerant of each other,” Cieri said. “The key to our success is the ability to cooperate and get along and learn from one another.”


Contributing Source: Duke University

Header Image Source: Wikimedia


Categories: General