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Feb. 3, 2015 - Skeptoid
13:38
Skeptoid #452: The Stone Spheres of Costa Rica

In Costa Rica, mysterious stone spheres left behind by the country's previous inhabitants seem to defy explanation. Learn about your ad choices: dovetail.prx.org/ad-choices

Transcriber: nvidia/parakeet-tdt-0.6b-v2, sat-12l-sm, and large-v3-turbo
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Costa Rica's Stone Spheres Mystery 00:12:03
Travel to Costa Rica and among the archaeological curiosities you may be fortunate enough to see are the famous stone spheres, great globes of solid rock carved more than a thousand years ago and weighing up to 15 tons.
What are they?
What were they used for?
What mysterious properties might they possess?
One thing we know for sure is that most of the info about them is false.
The truth behind the stone spheres of Costa Rica is coming up now on Skeptoid.
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Imagine yourself in southern Costa Rica in the 1930s.
You're a digger working for a banana plantation, excavating the shallow tropical soil to make way for another row of agricultural monophylet, replacing the once verdant and diverse forest.
Your shovel hits something hard, maybe an errant stone in the soil, so you work your shovel around the periphery to no avail.
As you continue to dig around the object, you eventually reveal a two-meter sphere made entirely of stone.
Having grown up in the region, you've heard stories about these stone spheres known locally as Las Bolas.
They're a thousand years old, carved with magic potions, perfectly spherical, and filled with gold.
Have you really stumbled upon an ancient magical relic?
Or is there a more plausible history for the object you've accidentally started digging up?
This story may sound far-fetched, but it is the sort of thing that happened when southwestern Costa Rica was being developed for agriculture.
Hundreds of stones, some only centimeters in diameter, others several meters, were uncovered.
Some were destroyed to try and find supposedly hidden treasures.
Others were taken to be put on display in and around the homes of Costa Rica's wealthy elite.
And thankfully, some were left in place or interred in the Museo Nacional de Costa Rica, or the Costa Rican National Museum, for preservation and study.
When they were first discovered, there was a brief period of intensive study, followed by a decades-long gap until interest was renewed in these stones in the 1970s, leading to their status today as objects worthy of archaeological investigation just like any other impressive Mesoamerican relics.
To date, over 300 stones have been found in the Diquiz Delta and on Isla del Caño.
The Diquiz Delta is named for the now-extinct Diquiz culture that used to inhabit the region.
Some of the spheres are made from sandstone or limestone, about a dozen spheres each.
The rest of the about 300 known are sculpted from Gabbro, all common rocks to the region.
Gabbro is an igneous rock that is chemically similar to something like basalt, but instead of cooling at the surface due to a volcanic eruption, Gabbro is plutonic, meaning it cools from magma into rock while still in the Earth's crust.
The idea of giant ancient stone spheres first entered popular culture in the film Raiders of the Lost Ark, when adventurer archaeologist Dr. Indiana Jones attempts to take a gold idol statue from an ancient temple in Peru.
He tries to replace the idol with a bag of sand of the same weight so as to not set off any of the elaborate traps left to deter thieves, but misjudges the weight and sets everything off anyways, culminating in him running full tilt away from a gigantic rolling ball lest he be crushed.
An iconic moment on screen, but in no way representative of the likely role of the spheres in Dequised society.
But before we get into what the sphere's likely purpose was, we should first examine some of the myths surrounding the spheres.
Some of these myths are more outlandish than others, such as the spheres being from the fictional island of Atlantis, or that the spheres were part of a game played by giants.
There are only a handful of these myths that require specific mention and scrutiny.
The first, as already referenced above, is that the spheres house great riches, like ancient stone piñatas.
It is also claimed that the stones were created using a potion to soften the rock, allowing them to be worked into perfect spheres.
Some say that the spheres have petroglyphs or carved symbols etched into them that can only be seen when wet.
To go through the myths in order, of all the stones that have been broken open, either on purpose or by accident, none have been anything other than solid rock.
A variation on the myth claims that the stones were shaped around a single coffee bean, which is unlikely considering the spheres were probably carved from a larger piece of rock, not formed around a central point, and the fact that coffee wasn't introduced to the New World until 1607 in the Virginian colony of Jamestown.
The idea of using a potion to soften the rock is often supported by work presented in the early 1980s by French archaeologist Joseph David Dovitz, whose work focused on how pre-Incan people could have disaggregated or broken apart stones using acids derived from local plants.
However, the stones in question were calcium carbonate-based, like limestone, and thus would respond to acid the same way an ant-acid tablet responds to your stomach acid.
But remember that the majority of the spheres in Costa Rica are gabbro, which is mafic, a type of rock made up of silicate minerals rich in magnesium and iron, none of which would be as reactive to acid as would be required to shape them as the legend suggests.
One of the most persistent myths about the stones is their perfect sphericity.
It's sort of an argument from antiquity that ancient peoples would have had some secret knowledge that allowed them to do something perfectly that we've only recently been able to duplicate with modern scientific techniques.
And while the stones display an amazing level of craftsmanship not to be discounted, it is also quite obvious that they are not perfect spheres.
Even a cursory inspection of easy-to-locate photographs of the sphere shows this.
Now it is possible, if not probable, that the spheres have changed their shape slightly over time due to erosion, but the inability to measure them as their original shape does not provide evidence to claim that they were perfectly spherical at some point in the past.
All we can measure is what we have left, and what we have left are not perfect spheres.
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Finally, the petroglyphs that can only be seen in the rain.
This is sort of an ironic claim, since including petroglyphs would mean that the stones couldn't be perfect spheres in the first place.
However, taking the claim at face value, we certainly have found some spheres that include petroglyphs or other carvings.
They can be seen while the stone is bone dry, but they are likely easier to see when the stone is wet.
Paleontologists use a similar technique when looking at fossil trackways.
A quick splash of water can make an impression in the rock much more obvious than looking at it while dry.
And while most of the spheres today seem smooth, it is possible that originally shallow petroglyphs could have been lost to the rigors of time and erosion.
The simple fact of the spheres is that they were made by the indigenous peoples of pre-Columbian Costa Rica, likely a part of the Diquis culture.
They first started being made around the year 600 and continued past the year 1000 but ceased production prior to the arrival of the Spaniards.
They represent another impressive example of the craftsmanship of people in that region prior to European contact, just like the pyramids of the Maya or the alpine cities of the Inca.
Part of the reason these stones became associated with more mysterious origins is because the culture of the Diquis, unlike the Maya or the Aztec, went extinct, so there was less cultural memory to draw upon as to their origin and original purpose, fueling myth and legend.
Further, research into their origin, manufacture, and original purpose was hampered by the fact that they were found on land owned by a corporation concerned with fruit farming, not archaeology.
And many stones were removed from where they were found so the wealthy could have them on display around their homes and in their gardens, thus destroying all the information about their provenance and original placement within a larger context.
You can't really roll a pyramid out of the way just so you can keep planting bananas.
Our current understanding of how the spheres were made is deceptively simple, but no less impressive.
Indigenous societies, working without wheels or draft animals, transported stone pieces of up to 15 tons to be sculpted into spheres without metal tools.
This would have required a high level of organization, time, and skill to accomplish, and should be recognized for the achievement it was.
That's likely how the spheres were made.
But why were they made and what were they for?
One of the most promising explanations as to the true nature of the spheres is that they may have been arranged to mimic the stars in the sky, a terrestrial map of the cosmos, sort of like a tropical spherical stonehenge.
The petroglyphs may have also added information about the stars, mapping constellations right onto the sphere to give extra information to a knowledgeable viewer.
But it is equally possible that the spheres were a status symbol for the wealthy and powerful, much in the same way they serve for the wealthy modern Costa Ricans who had the spheres brought to their homes.
The best way to answer these questions is through careful continued study and preservation.
The people of modern-day Costa Rica are proud of the heritage that their stone spheres represent, and they have every right to be proud.
The spheres represent some of the remains of a once impressive and advanced culture in the region they now call home.
The problem arises when the spheres are presented as somehow magical or mystical, either through honest belief or as a way to entice tourist dollars into the area.
Fortunately, with the recent advances in archaeology of in-situ sphere sites and the support of the Museo Nacional de Costa Rica, the tide is shifting in favor of understanding the spheres in their appropriate historical context.
The efforts have even borne fruit, as the settlements with in-placed spheres on the Dequis Delta were declared a UNESCO World Heritage Site in 2014.
There are many mysteries still surrounding the stone spheres of Costa Rica, but we have every reason to believe that with proper investigative techniques and scientific examination, we will progress in our understanding of the Dequis culture while still retaining a sense of awe at their artistic and technological accomplishments.
Unlocking Dequis Culture Secrets 00:01:32
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