The smell of death: its chemical pattern could become a powerful forensic tool

A forensic scientist investigating one of the final and less smelly stages of decomposition in cattle. Anil1956/wikipedia

Most people are able to recognise the smell of “death” when they encounter a dead animal on a farm or a roadkill. But despite its distinctive scent, few know why it actually smells the way it does. Even forensic scientists may not have identified all of the compounds behind it yet – they are still in the process.

Understanding the pattern of change of the chemicals that make up the scent during the process of decomposition could be of huge benefit to forensic science. Not only could it help determining the time of death of a victim, it could also lead to more scientifically rigorous training of cadaver dogs.

The smell of death is actually a very complex symphony of scents, with different notes waxing and waning as decomposition progresses. To date, more than 480 different volatile organic compounds have been captured and identified from human cadavers, and more than 800 have been identified from porcine cadavers.

My team (profiles here and here) has identified hundreds of chemicals given off by decomposing pig cadavers, both on land and under water. Porcine cadavers are frequently used for forensic research in the UK because of their physiological similarities to humans and the relative ease of obtaining them. There is currently no way for researchers to access human remains for this purpose, such as dedicated taphonomy facilities or “body farms”.

Our research used fluffy fibres to capture the gases given off by porcine cadavers enclosed in boxes, lying in air and in water, over a period of time. We then we used gas chromatography mass spectrometry (GCMS) to identify the individual volatile organic compounds absorbed by the fibres. GCMS identifies chemicals within a mixture on the basis of how long it takes each component to travel through a very long and thin column to an ionisation chamber and detector.

Surprisingly, some of the gases that make up the whole bouquet of death were actually quite pleasant – including hexane and butanol. Hexane is associated with the smell of freshly-mown grass and butanol smells of leaf litter and forest floors. These are present in the earliest stages of decomposition and then reappear in the very final stage, known as skeletonisation. In addition, in the first few days after death, these are accompanied by the smell of hexadecanoic acid, which is often said to smell like “old people’s homes”.

Pig carcass in the smelliest stage of decomposition: the bloat stage. Hbreton19 /wikimedia, CC BY-SA

Some of the worst smells come somewhere in the middle of the decomposition process. Chemicals released during the bloat stage, which occurs about a week after death (depending on the surrounding conditions), when intestinal bacteria are reproducing uncontrollably and producing vast amounts of farty gases, are more likely to have you reaching for the sick bucket. For example, the dimethyl disulphide and trisulphide, bring the smell of garlic and the stench of rotting cabbage to the proceedings.

At this stage indole also makes an appearance in high concentrations, imparting a strong faecal smell. At low concentrations, however, indole has a pleasant, flowery fragrance and is used extensively in the perfume industry.

Once the active decay stage is underway, maggots hatch and munch their way through the flesh of the cadaver, breaching the intestinal walls. At this stage, some more unpleasant smells join the heady mix. These include 2-methylbutanoic acid – which smells distinctly of “cheesy feet” or teenage bedrooms – and trimethylamine, which is the aroma of days-old fish. In addition, there is a strong undercurrent of butyric acid, which reeks of vomit.

As decomposition progresses, these substances are joined by other chemicals, including intoxicating amounts of phenol, which has a sweet, burning-rubber type smell. By the time skeletonisation occurs, the odour-producing bacteria have been replaced by more mechanical means of decay, and the obnoxious smells are replaced by more woody, wet notes.

Aromatic applications

Understanding the rhythm, rise and fall of these fragrant notes allows forensic scientists to attempt to decipher the “magic formula” that specially-trained cadaver dogs are looking for. Currently, we do not know exactly which combination of chemicals cause them to respond. If we did, we may be able to tailor the training aids of such dogs to find corpses at specific stages of decay – or under water – and improve the scientific rigour behind their training and assessment.

For example, it might be possible to stipulate that a certain combination of chemicals need to be recognised and consistently “indicated” on before a dog is allowed to be certified.

In the future, it may also be possible to use the various scents given off by a cadaver to determine cause of death, as some medical conditions may encourage certain bacterial growth. It could even be used to identify unknown individuals by using the scents like a “smelly fingerprint” using similar technology.

Armed police drones: not necessarily a bad idea, but we need to keep careful watch of these eyes in the sky

When drones uphold the law, who's writing the laws on drones? EPA

Drones are everywhere, and now – in North Dakota, at least – they’re armed. The state government recently passed an ordinance allowing the police to use drones equipped with non-lethal weapons such as tasers, tear gas or rubber bullets.

While this raises serious civil liberties issues, there are positive and negative aspects to this development. For example, the ability to deploy non-lethal force from the air may lead to fewer casualties. The spate of deaths caused on the ground by police shootings is marked: 779 people have been killed by the police across the US this year. One of those deaths occurred in North Dakota, compared with 48 in Florida and 129 in California.

The use of drones may lead to the police making better decisions, allowing operators to carry out reconnaissance, use non-lethal force, or no force at all. Although there has been considerable coverage of the rising use of military drones whose pilots are able to attack targets from a great distance, their rules of engagement have been narrowed. As Chris Woods shows in his measured analysis, Sudden Justice, unnecessary drone deaths can be controlled with proper rules of engagement and targeted attacks by drones may be preferable to wide-area bombardment or bombing.

If the drone operators themselves are properly monitored they will not be able to engage in the suspicious shootings that have caused such uproar in the US and led to the Black Lives Matter campaign. With proper rules of engagement, drone pilots should not be able to shoot individuals in the back, plant weapons or concoct false testimony to cover up their homicidal activities. If – and this is an important if – tightly-written rules of engagement and the need for warrants are combined with non-lethal force, this could conceivably reduce the disastrous death toll from police shootings in the US.

Having said that, “non-lethal” armaments include a wide range of measures. Rick Becker, the Republican state senator who introduced the law to ban all armed drones only to find it later amended, argued:

It’s a vast array. It could be a taser, sound cannons, pepper spray, beanbags, rubber bullets. You know, just about anything you can think of can be attached to a drone. Drones vary in size from a small bird up to the sort of 12-foot drones that can have a couple of cannons attached.

Some of the non-lethal devices that might be deployed, such as rubber bullets and tasers, have led to deaths in the past, and may in other cases cause permanent damage, such as tasers and the LRAD sound cannon, whose blasts of noise at more than 100 decibels can cause pain, confusion, nausea, and permanent loss of hearing.

Watching you, watching us. Dkroetsch

Using police drones is worrying for other reasons. Drones hovering above public protests, marches and gatherings recording demonstrators will further chill the right to protest – a right that is already deep in the chiller cabinet in Britain. There is also the matter of who authorises the use of non-lethal force to disperse demonstrations: if they are not used proportionately, sound cannons, pepper spray, baton rounds of various types and other weaponry may encourage police to control demonstrations or establish curfews with little risk to themselves. This will then further dissuade people from protesting.

It’s obvious that drones are not a bad thing per se; they can assist in air-sea rescue, in locating survivors after disasters and in verifying arms control or environmental agreements. But they can also kill, spy on people and discourage people from exercising their democratic rights.

But drones are here and coming in increasing numbers whether we like it or not, so the best way forward for civil society is to demand clear rules of engagement and proper accountability to avoid harm. Or perhaps the next stage might be for protest groups to crowdsource funding in order to purchase their own drones, so that state authorities might be more wary of deploying their own. The “right to bear drones” might be the next stage for civilian groups in the US – a sousveillance society, with our drone watching them while their drone watches us.

Hackers have finally breached Apple's security but your iPhone's probably safe (for now)

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Cyber security experts recently discovered that the almost impenetrable Apple App Store had been hacked. While cyber break-ins have become routine news for many companies, Apple has long prided itself on providing technology for its phones and tablets that was incredibly secure.

This was done by controlling how developers – the people who create your apps on your device – not only create their code but also upload it on to the app store. Steve Jobs ensured that Apple would check each app before it entered the marketplace, as well as the developers themselves, and the firm has enforced tight controls on what the devices could access.

This meant that Apple mobile products arguably were (and probably still are) the most secure you could buy. However a new attack dubbed XCodeGhost has done a great job of undermining Apple’s otherwise strong security.

The attack method used was cunning and, in a technical sense, impressive. Rather than attack the devices or the App Store, the hackers compromised the xcode framework, the underlying programming system used by developers to create the apps. This is akin to poisoning a city’s water supply at its source rather than attacking the settlement’s buildings or army directly.

App developers use a suite of software known as xcode to create programs for Apple devices. Within this is a large library of functions that enable each created app to talk to the underlying phone or tablet. Each library function has different roles, from allowing you to share your location to making your phone sound like a light sabre when you wave it around.

The hackers created a malicious program (malware) that used the internet to seek out Mac computers with xcode installed, gambling on the possibility that some of these devices were used to create apps for the Apple App store. It then dropped contaminated code library features into the xcode system. These will appear to do what the app developers programmed them to do but also capture and send personal data from your device back to the hackers.

Malicious intent Shutterstock

Security experts are concerned that this innovative attack leaves Apple open to future attacks. It attacks anyone who has this coding environment installed on their computer system and compromises the code before it enters the secured systems offered by Apple.

Not only is this embarrassing for the company, as their checks clearly missed this compromise. It is also embarrassing for the many developers affected as their own internal security and anti-malware processes have been compromised.

What does this mean for you?

If you are the owner of an iPhone or iPad, there is nothing you can do. Apple has never offered Apple device owners the opportunity to protect their own technology. Apple has owned this, controlled this and until recently has been very successful in protecting its products.

Android-powered devices have historically been relatively vulnerable to an excess of 40,000 types of malware. The equivalent number for Apple devices remains very low. However, this new and interesting attack means that attackers have established an alternative route into your device, through the framework used by app developers. They only need one compromised app from one compromised developer machine to be successful.

Different experts have already found multiple apps, such as Angry Birds 2, that are infected. Many of these apps are being updated in earnest by their creators to patch the security breach and new versions are automatically being installed on your iPhone or iPad. If you are ultra concerned you can delete the app and re-install in a few days time when you know it has been secured.

In order to prevent further breaches, Apple must review its security policies and how it checks all code before it enters their App Store. It also means that the onus is on all developers to improve the way they scan their own systems. Otherwise, Apple will refuse to allow them to participate in this otherwise very successful and secure system.

Rosetta scientists unveil the source of ice and dust jets on comet 67P

Comet 67P and its mysterious jets. ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA, CC BY-SA

After a decade-long journey through space, the Rosetta spacecraft has spent the past year less than 100km from the nucleus of comet 67P Churyumov-Gerasimenko, capturing some stunningly detailed images. But despite this wealth of visual evidence for researchers there is a lot we still don’t know about the comet – including why it is covered in organic material rather than just ice and what causes its powerful jets of dust and ice.

One of the big surprises of the Rosetta mission has been discovering just how dark 67P is: completely unlike an “dirty snowball”, which was how astronomer Fred Whipple described comets in the 1950s. Although images from missions to other comets have shown surfaces that are more likely to be mixtures of ice and rock, findings from an instrument called the Visible and Infrared Thermal Imaging Spectrometer onboard Rosetta have shown that 67P is rocky and almost completely covered in a layer of organic compounds – which was not expected. So where is all the ice?

Now researchers using the same instrument have come up with an answer. They discovered a day-night cycle of ice sublimation (where solid turns to a gas without first turning to liquid) and re-condensation linked to the amount of sunlight. In short, when parts of the comet are in shadow, it is cold enough for ice to form; when the sun shines on the surface, the ice disappears.

Rock as far as the eye can see. ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA, CC BY-SA

Yes, it might sound a bit obvious, but to dismiss this as “not exactly rocket science” is woefully unjust. The effects are not only on the surface, but extend to depths of several centimetres, leading to production of a layer where water could be active.

The information has even been used to uncover the mechanism by which the jets which shoot up from 67P’s surface form – one of the major goals of Rosetta’s mission. When the comet is lit up by the Sun, the boost in surface temperature triggers release of gas as the water ice sublimes. The study also helps explain how the comet’s surface has eroded: regions which are more deeply in shadow will experience a more reduced cycle of sublimation and condensation than regions where more sunlight can fall, leading to different patterns of rock fracturing and dust removal.

It is a beautiful example of how one set of results can help interpret a whole set of apparently unrelated phenomena. The idea of temperature cycles could be taken further to look at transport of molecules in the sub-surface layers and to investigate whether there is sufficient energy below the surface to allow chemical reactions to occur.

Probing the solar wind

Having found out how the jets of dust and ice form, Rosetta is now taking a three week break away from the nucleus, to travel to a more exotic location closer to the Sun. However, Rosetta will not be on holiday – far from it. Although the spacecraft will be 1500km away from the nucleus, it will still be observing the comet very closely. The excursion takes Rosetta to the bow of the comet, the region where the comet meets the solar wind.

Imagine that you are walking head-on into a fierce wind. As the wind hits you, it hurts! This is what is happening to 67P. The solar wind is a fast-moving stream of charged particles (mainly protons and electrons); 67P is a solid object moving against the flow. When the two meet, it is 67P which comes off the worst. The dust and gas around the nucleus get swept away, to form the tails of the comet.

The reason why Rosetta is taking the trip is because the bow shock of a comet has never been observed in detail before. Other cometary missions have flown past or through the shock region, but have never lingered. Studying the interface between the solar wind and the plasma region around another body is important because it will help us understand the physics of the interactions that are taking place between the particles. This is necessary because we have our own bow shock region where the Earth meets the solar wind.

Currents in the solar wind, which are modified at the bow shock, lead to changes in space weather (which affect satellite communications). While it might seem a bit of a stretch to suggest that measurements taken at a comet 270m kilometres (168m miles) away will help your mobile phone signal, it is by making such measurements that we will eventually be able to predict and ameliorate the effects of the solar wind at the Earth. Electronic devices work using information brought to them as electromagnetic radiation, but charged particles from solar flares can interfere with such devices, producing random signals.

So Rosetta’s excursion to the Sun will help keep us all in touch. Now, where’s Philae’s phone number..?

Disclosure

Monica Grady receives funding from the STFC and is a Trustee of Lunar Mission One.

Imagining strange new lifeforms could help us discover our own origins

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From the earliest of times, philosophers and scientists have tried to understand the relationship between animate and inanimate matter. But the origin of life remains one of the major scientific riddles to be solved.

The building blocks of life as we know it essentially consist of four groups of chemicals: proteins, nucleic acids, lipids (fats) and carbohydrates. There was much excitement about the possibility of finding amino acids (the ingredients for proteins) on comets or distant planets because some scientists believe that life on Earth, or at least its building blocks, may have originally come from outer space and been deposited by meteorites.

But there are now extensive examples of how natural processes on Earth can convert simple molecules into these building blocks. Scientists have demonstrated in the lab how to make amino acids, simple sugars, lipids and even nucleotides – the basic units of DNA – from very simple chemicals, under conditions that could have existed on early earth. What still eludes them is the point in the process when a chemical stew becomes an organism. How did the first lifeforms become alive?

Although there is some debate about the definition of life, it is generally recognised that all life requires the formation of a sustainable cell, and cells must be capable of reproduction. In human cells, this is done using strands of the chemical DNA. When cells divide, they use the DNA as a blueprint for how to make the new cells.

But cell division doesn’t always produce an exact copy of the DNA. Usually this copying mistake, or mutation, is a disadvantage and the cell can be discarded. But sometimes the mutation confers a benefit or advantage to the cell (or organism) in its present environment. In this case we say it is “selected”, meaning that it thrives and multiplies to the detriment of other cells.

A diatom – a single-celled algal organism – under the microscope. Frank Fox, CC BY-SA

It’s all in the chemistry

But how did the very first cells emerge? Living systems are chemically based and therefore must obey the laws of science. Life appears to be just a series of chemical reactions – and we now understand how these reactions work at the molecular level. So surely this should tell us how life came about?

A vesicle, a cell-like formation with a membrane made of fatty acids. Vesicle by shurikart/shutterstock.com

The conversion of these simple biomolecules into more complex ones has been observed under a variety of elementary conditions. For example, fatty acids – a type of lipid building-block molecule – naturally clump together into membrane-like structures, called vesicles, and even undergo chemical processes that resemble cell division and replication. Making simple replicating systems under self-sustaining conditions has also been shown to occur for both simple nucleotides (fragments of DNA) and peptides (fragments of proteins).

Creating order

The real problem is in understanding how this “machinery” of chemicals came together to generate life. The watershed where lifeless chemical activity is transformed into organised biological metabolism is extremely difficult to identify and the trigger for this is a key ingredient missing from the “primordial soup”.

The assumption that early life forms must have been similar to what we see today may be preventing us from answering this question. It’s possible that there were many unsuccessful precursors that bore little resemblance to present-day life. There has been speculation that primitive starting points could even have been based around an element other than carbon (the substance at the heart of all life today). Some researchers suggest that life may have originally evolved in liquids other than water. These alternatives are fascinating, but it’s difficult to find a starting point for researching them because they are so unfamiliar.

Off balance

A key trait that sets life apart from inanimate matter is its reliance on organisation. Molecules must be arranged in a specific way and replicate according to a detailed pattern. But the natural tendency of the whole universe is towards a state of equilibrium, or balance – where everything is spread out and nothing is ordered. Maintaining an ordered structure means life is constantly off-balance and this requires energy, which organisms must extract from their surroundings.

One way that organisms do this it to cause movement of molecules or even sub-atomic particles that can then generate energy for a cell. For example, organisms living in hydrothermal vents on the sea floor get their energy from the transfer of protons through the cell membrane.

Structure of a protein, as deposited in the Protein Data Bank. Matt Howard, CC BY-SA

Living systems maintain their “off-balance” state by combining the ability to self-replicate with the ability to extract energy from their surroundings. To discover the origin of life, we need to understand how these properties combined to form a sustainable unit.

Some scientists are adopting a top-down approach, attempting to answer this question by removing bits of a living cell to determine the minimum structure required to sustain life. Others are approaching it from the bottom-up by combining the building blocks in a primitive container to mimic a simple cell.

While both approaches may be enlightening, the precise moment of transition from chemical to life (and vice versa) still evades us. But the lack of discovery is fascinating in itself – it confirms that creating life is difficult and requires conditions that are no longer naturally present on the Earth. A breakthrough in this area would not only tell us the requirements for life, but also the circumstances of its emergence.

How to build the world's fastest car

Flock/Siemens/Bloodhound

In 2016, a team of engineers and adventurers will travel to the South African desert and attempt to become the first people to drive a car at 1,000mph. The British-made vehicle, Bloodhound SSC, is designed to smash the current world land-speed record of 763mph to become the fastest car ever built.

Amazingly, this incredible target isn’t even the project’s main goal. Breaking the land-speed record is nothing new for the UK, which has held the title for 79 of the past 100 years – and continuously for the last 32 years, most recently with Thrust SSC) driven by Andy Green. But when Green, along with previous record holder Richard Noble and the then science minister Lord Drayson, launched Bloodhound in 2008, their aim was to inspire the next generation of problem solvers to put their great talent into science, technology, engineering and mathematics.

The other goal, of course, was to challenge the country’s engineers to complete a world-class research and development project. But how do you even start to design and build a car that is hundreds of miles an hour faster than any other the world has ever seen? There are three main things to consider. Is it slippery enough? Is it powerful enough? And is it strong enough?

The slippery subject of aerodynamics

Anyone will know just from flying a kite that there is great power in the moving air. That’s fine if you are working with the airflow but with Bloodhound we will be trying to push against it faster than the speed of sound. Pushing an object through the air creates a tremendous amount of resistance force and the greater the frontal area of the object, the higher that resistance will be.

Thrust SSC used two jet engines to provide the power. These operate by sucking air in from the front, compressing it, burning fuel, and forcing it out the back to create thrust. This kind of design needs a large frontal area so the jet engines can scoop up enough air. But analysis showed a design like this would never be able to reach 1,000mph. The frontal area would generate so much resistance that you would never be able to produce enough power with current technology to counter it. Instead we had to design a vehicle with a smaller frontal area and that required the use of a rocket engine (more of that later).

To check the aerodynamics, a computer model was run at the University of Swansea using a system known as computational fluid dynamics (CFD). This enabled the team to understand how the car shape would respond to airflow over the bodywork at low speeds (subsonic), as it approached the sound barrier (transonic), and high speeds (supersonic). As a result, we were able to simulate more than 150 designs to ensure that we had a stable vehicle at any speed.

World’s biggest model kit? Stefan Marjoram/Bloodhound

Powering the beast

Because of the need for a small frontal area, two jet engines would be impossible. The solution was to combine a single jet engine with rocket power. Rockets can produce incredible power either by burning a mix of liquid fuel and liquid oxygen or by lighting an explosive mixture of solid fuel and oxidiser. The problem with both these models is the chemicals. Liquid oxygen is very difficult to manage and must be kept at -182°C. Rockets with solid fuel, once started, cannot be stopped until all the fuel is consumed. Once again a third way was needed.

We selected a hybrid rocket that uses very pure hydrogen peroxide (the stuff you may use to lighten your hair) as an oxidiser and a rubber grain as a fuel. This meant we could turn off the flow of oxidiser and stop the explosion, producing a controllable rocket.

But this created another problem: how to get the oxidiser into the rocket. With a solution suitable for a land-speed record, we used a high-powered Jaguar sports car engine to power a fuel pump that is able to deliver 1000l of peroxide to the rocket in 20 seconds. These three engines together should be enough to get us to 1,000mph.

Keeping it together

Another concern is that all of the components of the car are subjected to huge pressures. For example, the outside of the wheels spin so fast that they generate a force 50,000 times greater than the Earth’s gravity. That means that each gram of material has an effective mass of 50kg. Meanwhile, the shaft that drives the fuel pump must carry considerable torque while moving a liquid that would erode many materials.

To overcome these challenges, the wheels were forged from a single block of high-grade aluminium. This ensured the grains of metal that made up the block were all aligned, reducing the chances of a defect or a rupture. The body shell of the car has been manufactured from carbon fibre to ensure a light but incredibly strong structure. And the fuel pump drive shaft is manufactured from Custom 465, a material that is chemically unreactive but strong enough to turn the pump. We then thoroughly tested each component to replicate the forces it will experience during the record attempt.

All of these problems show how designing and building a car like Bloodhound requires a huge wealth of expertise. From the chemists who develop the materials to the engineers who work out how to manufacture the components and integrate them into a single working system, breaking the land-speed record is a cooperative project involving many more people than just the driver. When the car makes its nerve-biting record attempt in 2016, it’ll be as if they’re all in the cockpit with him.

Phil Spiers is a Fellow of the Royal Aeronautical Society

Found: 9,000-year-old case of ritualistic beheading that may be oldest in Americas

Decapitated head with amputated hands laid over the face were found at the burial site. Strauss et al., CC BY

From 19th-century tales about tribes hunting for “trophy heads” to Hollywood films such as Mel Gibson’s Apocolypto, the Amazon rain forest has long inspired gruesome stories about ritualistic killing. However, the portrayal of civilisations such as the Incas, Nazcas, and the Wari cultures making human sacrifices in South America may have a much longer tradition than previously thought.

A new study, published in PLOS One, reports the discovery of a 9,000 year-old case of ritualised human decapitation that seems to be the oldest in the Americas by some margin.

Execution or burial?

The researchers found the remains of the beheaded young man from a rock shelter in Lapa do Santo, East-Central Brazil. Quite astonishingly the decapitated remains date to between 9,100 and 9,400 years ago.

The decapitated skull was found with an amputated right hand laid over the left side of the face, with fingers pointing to the chin. It also had an amputated left hand laid over the right side of the face with fingers pointing to the forehead, making it highly ritualistic and extremely unusual.

Plastered skull from Jericho in the British Museum. Jononmac46/wikimedia, CC BY-SA

The decapitation is reminiscent of Neolithic skull cults from the Middle East, which often buried their deceased under the floors of their homes – sometimes with the skull removed, plastered and painted. The placement of the hands is also similar to partial coverage of face gestures that we see in different cultural settings today (such as signs of tiredness, shock, horror etc).

However, the process of extracting the body parts from the victim seems straight out of a horror movie. The man was decapitated by blows from a sharp instrument to the neck, but there was also evidence that the head was distorted and twisted in places, suggesting there was difficulty getting the head off the body. Furthermore, the cuts left on the bones were signs that the flesh had been removed from the head prior to it being buried. However, there’s no evidence to suggest decapitation was the cause of death.

Discovered parts. Strauss et al.

This ritualistic behaviour may seem barbaric to us today but it is becoming clearer that during the Neolithic period decapitations, skull cults and ancestor worship were an important cultural practice. Excavations of neolithic sites in the Middle East have uncovered ancestors that had their fleshed removed in a similar way before being buried in the houses of their relatives.

The rituals undoubtedly involved many of the community to honour their ancestors and may be similar to what has been discovered at Lapa do Santo.

Local but unusual man

The researchers also undertook a number of scientific analyses to find out more about the individual. One of these was to analyse the teeth for isotopes of strontium, which is taken up in the human body through food and water. The analysis of the tooth enamel, which is formed during childhood can be compared to the isotope signatures in the local geology. This can tell whether or not the individual was related to the place they were buried.

The analysis showed that the man was clearly associated with his place of burial. This implies he was a local man who grew up in the area and not a captured trophy from a warring faction.

But perhaps most intriguingly, they took measurements of the skull and compared it to measurements of other skeletons, including ones excavated at the same site. In this case the young man’s head was a little bit of an outlier on the overall size of the skull, being slightly larger. Did he look different to the other men? Was he somehow distinctive? The remarkable evidence from this site suggests he was unique to their community but living with them and perhaps chosen for this reason?

This forensic approach to understanding archaeological remains is now shedding light on how much information can be gleaned from these deposits and the value of careful and meticulous work.

More broadly, this is one of many revelations that are starting to appear regarding South American archaeology ranging from evidence of early extensive burning of the landscape 9,500 years ago, through to large-scale deforestation and the production of glyphs by pre-European culture.

It remains to be seen how many more discoveries like this will be made in the future but there is one clear message, losing your head in South America is not a new phenomenon!