There is growing evidence that termites have a substantial, but still poorly understood, role in the carbon cycle.

We used radiocarbon dating; dating the mounds, we reasoned, would allow us to see when minerals that were stored in the mounds were flushed to the groundwater.

The tests revealed far more than we expected: Namaqualand’s heuweltjies, it turns out, are the world’s oldest inhabited termite mounds. Some date as far back as between 34,000 and 13,000 years. The oldest previously known inhabited mounds were 4,000 years old (from a different termite species from Brazil) and 2,300 years old (from central Congo).