National Geographic News
stone-tipped-projectiles.jpg

The discovery of stone-tipped projectiles in Ethiopia like the one pictured above may have been used for striking animals from a distance.

Photograph by TD White

Locater map of Gademotta Formation in Ethiopia.

Charles Q. Choi

for National Geographic

Published November 26, 2013

The oldest known stone-tipped projectiles have been discovered in Ethiopia. The javelins are roughly 280,000 years old and predate the earliest known fossils of our species, Homo sapiens, by about 80,000 years.

These javelins are some 200,000 years older than previous examples of similar weapons, suggesting that modern humans and their extinct relatives had the know-how to create these sorts of complex thrown projectiles much earlier than often thought.

Scientists investigated stone tools unearthed at the Gademotta Formation on the flanks of an ancient, large collapsed volcanic crater in central Ethiopia's Rift Valley.

"Today, the area represents a ridge overlooking one of the four lakes in the vicinity, Lake Ziway," said researcher Yonatan Sahle, an archaeologist at the University of California, Berkeley. (See "Stone Spear Tips Surprisingly Old—'Like Finding iPods in Ancient Rome.' ")

During much of the Middle Pleistocene, about 125,000 to 780,000 years ago, "the area was overlooking an even bigger paleolake—a megalake composed of today's four separate lakes." Antelope and hippo remains have been recovered from the grassy, forested site.

The oldest artifacts at the site are roughly 279,000 years old. In comparison, the earliest known fossils of Homo sapiens, previously discovered at sites elsewhere in Ethiopia, are about 200,000 years old.

Pointed artifacts with damage suggesting they were used in spears are common at the site. The researchers focused on 141 such obsidian artifacts.

The Tip of the Spear

"We were only interested in testing the hypothesis that these tools were definitely used to tip spears," Sahle said. "The eureka came much later as we did the analysis and found out that the features we were dealing with were the result of throwing impact, not thrusting."

When pointed artifacts are used as weapons, V-shaped fractures, called fracture wings, can form at the moment of impact; the apexes mark where the cracks started. Past experiments in materials such as obsidian have shown that the narrower the V-shapes of fracture wings, the higher the speed of the fracturing that created them.

The researchers discovered that the fracture wings seen in a dozen of these obsidian points suggest that the fracture cracking sped faster than 1,820 miles an hour (2,930 kilometers an hour).  In experiments with thrusting spears, that's the maximum velocity seen in fracturing. And some of these artifacts apparently developed fractures after impact at speeds of up to 3,345 miles an hour (5,385 kilometers an hour), close to the maximum velocity seen with fracturing in thrown spears.

A number of these artifacts are among the oldest at the site, suggesting that javelins were used as early as 279,000 years ago. Such weapons are considered signs of complex behavior and were pivotal to the spread of modern humans.

"The implication is that certain behavioral traits that are considered complex and mostly only the domains of anatomically modern humans—such as the capacity to make and use projectiles—were not only incorporated into the technological repertoire of the African early Homo sapiens, but also had earlier roots and were present in populations ancestral to Homo sapiens," Sahle said.

Advantages of Throwing

The invention of projectile weapons was a major advance over thrusting spears carried in hand. Projectiles empowered prehistoric hunters to strike at a distance, reducing the risk of injury from dangerous animals and broadening the range of prey that people might capture.

Paleoanthropologist John Shea at Stony Brook University, in New York, who did not take part in this research, said these findings were sound.

"In this area, I can see these thrown spears probably being used against crocodiles, hippos, or some other big animal that one could get close to with boats," Shea said.

Stone-tipped hunting spears appear in the fossil record beginning about 500,000 years ago. However, these were thrusting spears, not thrown javelins. Until now, the oldest conclusive evidence dated such projectiles at 80,000 years old.

The creator of the most ancient obsidian javelins found at Gademotta was probably Homo heidelbergensis, the most likely ancestor to modern humans and Neanderthals, Sahle said. There may be no way to determine whether Homo sapiens discovered how to make these weapons independently or if they learned how to do so from Homo heidelbergensis.

Shea noted many complex behaviors started appearing between 200,000 and 300,000 years ago. "You see a shift in anatomical structures that would have allowed us to speak, and a shift toward more complex tools," he said. "I think the advances seen here in tools have to do with the emergence of language."

Shea cautioned not to read too much into the fact that these findings were made in Ethiopia. "It's often assumed that the earliest discovery of anything is the first instance of anything," Shea said. "This is just the oldest example we have so far of this technology—it doesn't mean that this is where it first evolved."

He suggested similar research could be conducted at other sites "to see how widespread similar points are, to see if everyone at this time is doing the same thing or if there are regional differences."

In the future, the researchers would like to discover when humans began using even more complex mechanically propelled weapons, such as the bow and arrow, and the spear-thrower known as the atlatl, which may have been developed between 60,000 and 100,000 years ago. These weapons may have helped modern humans expand out of Africa and outcompete Neanderthals, they noted.

The scientists detailed their findings online November 13 in the journal PLOS ONE.

Follow Charles Q. Choi on Twitter and Google+.

69 comments
Jason Moan
Jason Moan

Just goes the show, scientists claims' regarding our history and the history of the universe are only educated guesses. Very little of what scientists claim to be true is actually based on fact. I have a hard time relying on carbon dating as an acceptable form of measurement. Carbon dating assumes that the radiation on our planet has ben constant. Catastrophic events such as meteoric impacts and solar flares could have spiked the level of radiation in our atmosphere at different times during Earth's existence.

Ali B.
Ali B.

homo sapiens is only a transient form of humanity, with ancestors, descendents and cousins

Martial Broussard
Martial Broussard

Note to Seamus: The speeds noted in the article are fracture speeds, not spear velocities. Please reread, I admit a quick scan may be confusing.

pierre pierre
pierre pierre

I still use them in the neighborhood. I admit; I am a spear chucker.

Séamus Allister
Séamus Allister

There's BS in here... "some of these artifacts apparently developed fractures after impact at speeds of up to 3,345 miles an hour" - The speed of sound is 761 MPH. So they're saying these spears were traveling at almost Mach 4.4.

Vera C.
Vera C.

Back in the eighties I found a couple of obsidian arrowheads in the Rift Valley in Kenya; one complete one and one incomplete, i.e. the chipping into shape was only partial. I wonder how old they are

Randy Reno
Randy Reno

It seems to me that everybody is reading to much into the article.  Maybe's and might's have been used, so nothing yet is settled.  These spears might have been used more for self defense.  After all, these humans lived around a large lake and probably ate  more fish than anything else! 

Frank Schmidt
Frank Schmidt

I don't get it!  How do you throw a javelin at any thing near the speed quoted?

I must be missing something here.

Stephen Kuhl
Stephen Kuhl

Forgive me if this has been explained.

How does anyone know the age of a spearhead? I understand Carbon dating which measures the age of the material itself. But surely the material of the spearhead could be very much older than the date at which it was formed into a usable shape. So, how do they figure out the age at which it was 'sharpened'?

Yael Hsu
Yael Hsu

Evolution is a hoax - don't you understand it by now?

Ryan Vars
Ryan Vars

could it be that we don't know as much about early human history as we think we do? and maybe our methods of dating aren't as accurate as we hope them to be...

Mark Glaab
Mark Glaab

I see a major problem with this new discovery and it is reassessing population growth. Supposedly, the population grew from a few in 275,000bc to a paltry 1 million people in 10,000bc. They then populated to 5 million in 1,000bc, only 5 thousand years later.

If they had the javelin in 275,000bc I can guarantee that this was not their only innovation. Someone will have to go back to the drawing board on population growth because people with spears will not have almost totally stagnant growth for hundreds of thousands of years. Since plagues wiping out a whopping 50% of the population take only 200 years to replenish, you cannot invent enough plagues, infant deaths, accidents, floods, volcanos and hoards of sabre-tooth tigers to keep the human population that stagnant for this long. This is simply not believable for people who had, at minimum, javelins and the sense to use them for attack and defense.

If I was a population expert reading this article, I would be ordering a "crate" of aspirin to be wheeled in on skids!

Jason Vance
Jason Vance

How can we be sure that this object was designed by humans? Would wind, rain, and erosion not produce the same shape in a  piece of rock?

Sam Fort
Sam Fort

Owwi.....In your print edition of Nat Geo, did you note the article on mountain lions?

Merbis Cuenca
Merbis Cuenca

Very interesting I just  have found this kind of projectile in Sauth America Venezuela

Merbis Cuenca
Merbis Cuenca

very interesting but Ihave faund like this in VENEZUELA

David Reid
David Reid

As both an engineer and a former baseball player I can say most people don't appreciate how complex the ability to throw something overhand is anatomically. If I remember correctly chimps can only throw a rock at about half the speed of a human, with far less accuracy. There had to be a lot of evolutionary changes from proto-human ape towards modern humans to accomplish this. I'm not surprised this ability didn't "suddenly" appear as well as the tools to utilize it. The ability to kill or defer predication at a distance (by accurately hurling rock and spears) is a major evolutionary survival skill for an animal that has few natural defenses like humans. 

Even with humans females who don't learn how to throw overhand (ie"throw like a boy") before age 7-9 can never master the ability later in life (for men to understand this try throwing a ball left-handed if your a natural righty). I don't find this finding that surprising at all.

Kriss Forrester
Kriss Forrester

so cool love stuff like this  never know what could be dug up next  


Lon Otterby
Lon Otterby

Okay the fracturing speed is exceeded because the point shows fractures. How do you account for this?

Lon Otterby
Lon Otterby

How is it possible to throw a spear at more the 5 times the speed of sound?

Qi Chen
Qi Chen

cool.wonderful shape

Cedric Boisdon
Cedric Boisdon

yes , those number about fracturing speed make no sense as they are , unless our ancestor had develop kinetic energy penetrator for tanks, but that's unlikely...

Patrick López
Patrick López

How could a spear tip travel in excess of the speed of sound? Or am I misunderstanding what they are saying about the stress fractures?

Séamus Allister
Séamus Allister

A 0.5 kg spear traveling at this velocity would have a kinetic energy of around 94 TJ. If it didn't atomize on impact, it would penetrate whatever target it encountered and travel for several miles, making it impractical as a weapon, since it would be irretrievable. There's also the small matter of generating the energy required to accelerate the spear in the first place.

Tom Carberry
Tom Carberry

@Stephen Kuhl They don't know.  Dating amounts to "educated" guess work.  Some person makes an "educated" guess and then everyone else follows suite.

They try to date from layers of sediment and other methods, but everything relies on guesstimates and even the slightest error in the guesstimate --for instance how long does it take for a millimeter of sediment to build up -- can lead to massive errors.  Few people understand the rapidity of increase in math errors or numbers.  Take a chess board (or a checkerboard) and put a penny on square one, two pennies on square two, 4 on 3, 8 on 4, then 16, 32, 64, etc.  By square 64 you will have a nice nest egg.

Archaeology and anthropology have attracted a lot of dedicated and sincere scientists and scholars, but because of the nature of the "sciences," with little actual science behind them, they also have a lot of errors and down right frauds.

Take dating of ancient history, which almost all middle eastern researchers base on Egyptian chronology, which in turn the Egyptologists base on data that no reputable historian would accept.  Unfortunately, Egyptology gained an enormous foothold in archaeology in the 19th century and before, and this has distorted everything else.  Tons of charlatans in Egyptology.

Michael Lovett
Michael Lovett

@Stephen Kuhl by the depth of the sediment and actual other organic evidence found in, near, and around that same level is how they date it.

Heidi Harper
Heidi Harper

@Ryan Vars I thought the same things after reading this. I'd say we definitely don't know as much about early human history as we think we do- we only have bits and pieces, and like you said our methods of dating might not be as accurate as we think they are which could make a big difference.  

Tom Carberry
Tom Carberry

@Mark Glaab 

Couple of different answers to your point.

First, we know almost nothing about ancient human history and probably will never know much.  All of the bones of ancient humans found by the Leakeys and others in Africa would fit into less than one banker's box.  Massive sheets of ice covered most of the northern hemisphere for thousands of years.  They crushed everything they passed over.  Look at the moon with all its craters and compare it to the Earth with few visible ones.  Living planets constantly hide the past.

Second, genetic evidence suggests pre-agricultural human populations had low birth rates because of their extreme physical fitness, because fitness can reduce or even eliminate menstruation.  With agriculture, humans became much smaller and less fit, and went forth and multiplied.  Even with higher fertility, populations generally stay low.  

Some historians classify societies by A, B, C, and D as far as mortality and ages.  In A you have a high birth rate, high death rate, and a stable population, with many under 18.  In B, you have a high birth rate and a falling death rate, and a rising population (like Europe and America the last few hundred years), with many in their prime 18-45.  In type C, you have a falling birth rate, falling death rate, and a stable population, with many middle aged (over 30).  In type D, you have a falling birth rate, a rising death rate, and a shrinking population, with many old people (over 50), like Europe today.

Agriculture not only made people less fit and much smaller, but it also reduced the average human brain by over 10% in size since the dawn of agriculture less than 10,000 years ago.  Yes, our ancestors had bigger brains than we do, but we could recoup the loss (and many have, because the 10% goes over populations, not individuals) by diet.  Give up all grains as a first step, because they make you small, stupid, and angry, in a pleasant croissant type way.

Heidi Harper
Heidi Harper

@Mark Glaab This is interesting, but isn't historical population growth more of a educated guess than an absolute? I'm no expert and don't know much about how the experts have come to their conclusions about population growth, but as this article (as well as others) shows we are still discovering new information about earth's past which could cause us to re-evaluate a lot of the knowledge we have. 

Stephen Brady
Stephen Brady

@Jason Vance 
The researchers focused on 141 such obsidian artifacts. 

The odds that it happened naturally are astronomical. More likely your going to knock on my front door trying to sell me a pineapple before we are both hit by lightening  

Richard Verstegen
Richard Verstegen

@Lon Otterby Where the speed of the javelin is concerned, I think there should be dots between the numbers instead of comma's. The speeds should be read as 'roughly 2 and a half miles an hour', or 'allmost 3 kilometers an hour'.

David Reid
David Reid

@Lon Otterby It's not the speed of the spear in flight that is being measured. It is the speed of the shock wave traveling through the spear after the spear impacts. 

Basically the spear hits a solid object after traveling 50-60 mph, as it impacts the target a shock wave is generated and travels through the spear at hyper-sonic speeds. Or think of it this way, when you clap, your hands don't fly together at faster than the speed of sound. But the shock wave generated by the impact of your hands travels through the air at that speed, that shock wave from the impact is known as "sound".  

David Webb
David Webb

The Nat Geo author has things mixed up. Those high speeds refer to the speed of the fractures in the rock, not the speed of the spears.

August Pamplona
August Pamplona

@Séamus Allister I had the same problem. I even wondered if the number separator was meant to be interpreted as a decimal point (which makes the projectile too slow for a spear). Then I realized that, as others are pointing out, they are talking about the propagation speed of the fracture front in the spear tip. I have no idea how one would make an estimate of that but that's what they are talking about.

Wagner Schorr-Ratzlaff
Wagner Schorr-Ratzlaff

@Tom Carberry @Mark Glaab

"but we could recoup the loss (and many have, because the 10% goes over populations, not individuals) by diet.  Give up all grains as a first step, because they make you small, stupid, and angry"


Lamarkian logic at it's finest

Heidi Harper
Heidi Harper

@Stephen Brady @Jason Vance Like Stephen said, really not likely it was natural erosion. To achieve this sort of shape and sharpness a process called flint knapping is used. 

Vera C.
Vera C.

@Stephen Brady

The English words lightening and lightning are only one letter apart in spelling and pronunciation, but worlds apart in meaning. The lightning bolt of comprehension you get after reading this lesson will start lightening your confusion.
 

Lightening

Lightening is the present participle of the verb "to lighten," and refers to the process of making something lighter in color. Lightening is the opposite of darkening, or making something darker.

I'm lightening my jeans by adding bleach to the wash. The dark blue will become light blue.

He's lightening the room by painting it white.


Lightening
also refers to the process of making something lighter in weight. Lightening is the opposite of making something heavier.

By using more plastic in place of metal, and thereby lightening cars, we can get better gas mileage.

The trick to lightening a cake is using beaten egg whites.


Lightning

Lightning is a noun - it refers to the meteorological phenomenon that is followed by thunder.

Lightning tends to strike the tallest thing in its vicinity.

The lightning storm caused the forest fire.

Séamus Allister
Séamus Allister

I was thinking that subsequently myself. Very ambiguous writing in this article for Nat Geo. Thanks, dude!

Behailu Habte
Behailu Habte

@David Webb WHY?? The field of Archaeology is multidisciplinary; it borrows diverse social and natural science theories and explanations so as to address hypothetical questions. These hypothetical question is raised in the minds of archaeologists.  In this regard,  the archaeologists may require to involve the naturalist in their research . This may be the reason why  Hutchins (the physicist ?) is involved in this analysis. I hope  well acknowledged being the co-author of the publication. What is the big deal then if Dr. Yonatan is taken the credit ?

David Webb
David Webb

It's measured from deformation marks left on the stone. It's actually done by one of the co-authors and not Sahle at all. Hutchins, who seems to have some background in engineering, developed the technique for his doctoral research in the late 90s. It's amazing work that nobody else in archaeology is doing. It's a shame that Sahle is getting most of the credit here.

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