|Llama dung helps Incas thrive, study shows. (Photo: Sergio Neves)|
ANDINA –– A study has indicated that the inhospitable Andean highlands of Peru could nurture the great Inca civilization that dominated South America for hundreds of years due to llama dung.
The study led by Alex Chepstow-Lusty of the French Institute of Andean Studies in Lima, Peru, showed that maize pollen, which was South America’s most important crop, suddenly appeared in lakebed mud 2,700 years ago, New Scientist reported.
Until then it seems that people mostly ate wild foods such as quinoa. Though popular in modern health-food shops, quinoa seeds could not have sustained a large and thriving civilization.
It is supposed that the sudden emergence of this crop 3,350 meters up in the Andes was due to the temporarily warmer climate, said Chepstow-Lusty.
His mud cores revealed that around the same time as maize pollen became dominant, the remains of oribatid mites also increased. These soil-dwelling bugs eat animal excrement, including llama dung.
Llamas are indigenous and were domesticated about 3,500 years ago. But around 2,700 years ago, the extra mite remains in the mud suggest that the hills were suddenly alive with large numbers of llamas: a bonanza of llama excrement would have fuelled the mite population boom. The dung would have been spread on fields as fertiliser, then leached into the lake.
The droppings would have made all the difference to the advancement of civilization, said Chepstow-Lusty.
"The widespread shift to agriculture and societal development was only possible with this extra ingredient – organic fertilisers on a vast scale," he added.