No cave art site contains more than 13 marks, matching a lunar month calendar. None of the sites in the database contain more than 13 marks, aligning with a 13 lunar month calendar Lunar year totals 354 days, 11.24 days short of a true solar year (365.24 days) Sumerians added a leap month to compensate; Gregorian calendar reform of 1582 by Pope Gregory XIII addressed a 10-day drift

One striking pattern: no site in the database contains more than 13 marks, lining up neatly with a 13-lunar-month calendar. A lunar year totals 354 days, falling 11.24 days short of the 365.24-day solar year. Earlier researchers March (1991) and Overmont (2019) proposed similar time-tracking interpretations of cave markings.

Key Facts

  • None of the sites in the database contain more than 13 marks, aligning with a 13 lunar month calendar
  • Lunar year totals 354 days, 11.24 days short of a true solar year (365.24 days)
  • Sumerians added a leap month to compensate; Gregorian calendar reform of 1582 by Pope Gregory XIII addressed a 10-day drift
  • March (1991) and Overmont (2019) previously proposed similar time-tracking interpretations