It’s popular knowledge that the age of the menarche – the first menstrual period – has been getting younger and younger throughout the modern time. This may be correct, but it doesn’t mean that there hasn’t been times with menarche at an even much younger average age. In this study I found via @neuroskeptic I learned that the Paleolithic female menarche occurred at an age… between 7 and 13 year.
I checked the study how they could tell this, so if you wonder:
These estimates obtained from skeletal remains, e.g. limb length, although they have obvious limitations, they are strengthened from comparative primate data. Assuming that full reproductive capacity is attained two years after menarche the authors suggested that in Paleolithic times girls were reproductively mature at the age of 11 to 13 years.
Menarche denotes the onset of the female reproductive capacity. The age that menarche occurs is mostly attributed to the interaction of genetics and various environmental factors. Herein, the author describes the evolution of the age at menarche from prehistoric to the present times. Data from skeletal remains suggest that in the Paleolithic female menarche occurred at an age between 7 and 13 years, early sexual maturation being a trade-off for reduced life expectancy. In the classical, as well as in the medieval years, the age at menarche was generally reported to be at about 14 years, with a range from 12-15 years. A significant retardation of the age at menarche occurred in the beginning of the modern times, soon after the industrial revolution, due to the deterioration of the living conditions, most studies reporting menarche to occur at 15-16 years. In the 20th century, especially in the second half of it, in the industrialized countries, the age at menarche decreased significantly, as a result of the improvement of the socioeconomic conditions, occurring between 12-13 years. In the present times, in the developed countries, this trend seems to slow down or level-off.