Errors and Misinformation
Several authors have now contributed to widespread misinformation about the stone balls of Costa Rica, leading to unfounded speculation about their nature and origin.
The Size of the Balls
In an article in Atlantis Rising Online, George Erikson makes exaggerated claims for the size of the stone balls, writing that they are "weighing up to 30 tons and measuring up to three meters in diameter" According to Samuel Lothrop, author of the most extensive study of the balls, "A 6-foot ball is estimated at about 7.5 tons, a 4-foot ball at 3 tons and a 3-foot specimen at 1.3 tons" (1963:22). Lothrop estimated the maximum weight for ball was around 16 tons. The largest known ball measures 2.15 m in diameter, which is substantially smaller than three meters.
The Roundness of the Balls
Erikson also states that these objects "were perfect spheres to within 2 millimeters from any measurement of both their diameter and circumference." This claim is false. No one has ever measured a ball with a sufficient degree of precision to make it. Neither Ivar Zapp nor George Erikson has proposed a methodology by which such measurements could be made. Lothrop (1963:17) wrote: "To measure the rotundity we used two methods, neither completely satisfactory. When the large balls were deeply buried in the ground, it might take several days to trench around them. Hence, we exposed the upper half only and then measured two or three more diameters with tape and plumb bob. This revealed that the poorer specimens, usually with diameters ranging between 2 and 3 feet (0.6-0.9 meters), varied in diameters as much as one or 2 inches (2.5-5.1 centimeters)." It should be clear that this method assumed that the portion under ground was spherical. Lothrop also measured balls that were more completely exposed by taking up to five circumferences with a tape measure, from which he then calculated their diameters. He writes, "Evidently, the larger balls were the product of the finest craftsmanship, and they were so nearly perfect that the tape and plumb-bob measurements of diameters did not reveal imperfections. Therefore, we measured circumferences horizontally and, if possible, at a 45-degree upward slant toward the four cardinal points. We did not usually ascertain the vertical circumference as the large balls were too heavy to move. This procedure was not as easy as it sounds because several people had to hold the tape and all measurements had to be checked. As the variation in diameters was too small to be detected by eye even with a plumb bob, the diameters have been computed mathematically". The source of claims for precise measurements may stem from misinterpretations of Lothrop's tables, in which he presents the calculated diameters in meters to four decimal places. However, these are mathematically calculated estimates, not direct measurements. They have not been rounded to reflect the actual precision with which the actual measurements were taken. It should be obvious that differences "too small to be detected by eye" cannot be translated into claims about precision "to within 2 millimeters". In fact, the surfaces of the balls are not perfectly smooth, creating irregularities that plainly exceed 2 millimeters in height. As noted above, some balls are known to vary over 5 cm (50 mm) in diameter. In the photograph of the largest ball on this web site, it is clear that the surface has been badly damaged. It is therefore impossible to know how precisely formed this ball might have been.
The Makers of the Balls
George Erikson states that "archaeologists attributed the spheres to the Chorotega Indians". No archaeologist familiar with the evidence has ever made this claim. The Chorotega were an Oto-Manguean speaking group that occupied an area of Guanacaste, near the Gulf of Nicoya in northwestern Costa Rica. The peoples who lived in the area where the balls are found were Chibchan speakers. The balls have been found in association with architectural remains, such as stone walls and pavements made of river cobbles, and both whole and broken pottery vessels that are consistent with finds at other sites associated with the Aguas Buenas and Chiriquí cultures. These are believed to represent native peoples ancestral to historical Chibchan-speaking group of southern Costa Rica.
The Dating of the Balls
George Erikson and others have implied that the balls may date as early as 12,000 years ago. There is no evidence to support this claim. Since the balls cannot be dated directly by methods such as radiocarbon dating, which can be applied directly only to organic materials, the best way to date them is by stratigraphic context and associated artifacts. Lothrop excavated one stone ball that was located in a soil layer separated from an underlying, sherd-bearing deposit that contained pottery typical of the Aguas Buenas culture (200 BC - AD 600). In the soil immediately beneath this ball he found the broken head of a painted human figurine of the Buenos Aires Polychrome type, dated to AD 1000-1500 (examples have reportely been found associated with iron tools). This suggests the ball was made sometime between AD 600 and 1500.
The Balls are "Out of Context"
Since their discovery in 1940, the vast majority of these balls have been removed from their archaeological contexts to serve as lawn ornaments across Costa Rica. Many of the balls studied by Lothrop appeared to have rolled off of nearby mounds. Several had been covered by layers of fine silt, apparently from flood deposits and natural erosion. Naturally, they are "out of context" in the sense of having few good archaeological associations.
Scholars Have Ignored Them
It is not unusual for authors who write about the stone balls to claim that these objects have received inadequate attention from serious scholars. While this is undoubtedly true, it is not true that these objects have been ignored. It is also not true that scholarship regarding them has been somehow hidden from the general public. The first scholarly study of the balls was undertaken by Doris Stone immediately upon their discovery by workers for the United Fruit Company. Results of her investigation were published in 1943 in American Antiquity, the leading academic journal for archaeology in the United States. Samuel Lothrop, an archaeologist on the staff of the Peabody Museum of Archaeology and Ethnography at Harvard University, undertook major fieldwork concerning the balls in 1948. The final report on his study was published but the Museum in 1963. It contains maps of sites where the balls were found, detailed descriptions of pottery and metal objects found with and near them, and many photographs, measurements, and drawings of the balls, their alignments, and their stratigraphic contexts. Additional research on the balls by archaeologist Matthew Stirling was reported in the pages of National Geographic in 1969. In the late 1970s, archaeological survey on Isla del Caño (published in 1986) revealed balls in offshore contexts. Sites with balls were investigated and reported in the 1980s by Robert Drolet in the course of surveys and excavations in the Térraba Valley. In the late 1980s and early 1990s, Claude Baudez and his students from the University of Paris returned to the locations of Lothrop's earlier fieldwork in the Diquís delta to undertake a more careful analysis of the pottery of the area, producing more refined dates for the contexts of the balls. This research was published in Spanish in 1993, with an English summary appearing in 1996. Also in the early 1990s, the author undertook fieldwork around Golfito, documenting the existence of the easternmost examples of these balls. At this time, Enrico Dal Lago, a student at the University of Kansas, defended a Master's thesis on the subject of the balls. The most careful study of the balls, however, has been fieldwork undertaken from 1990-1995 by archaeologist Ifigenia Quintanilla under the auspices of the National Museum of Costa Rica. She was able to excavate several balls in situ, documenting the process of their manufacture and their cultural associations. Quintanilla's research has been the most complete field study of these objects since Lothrop. While still mostly unpublished, the information she collected is currently the subject of her graduate research at the University of Barcelona. Even with current research pending, the list of references on this Web site makes it clear that the stone balls have received a great deal of serious, scholarly attention.
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