The purpose of this volume is to gather interdisciplinary scholars to explore and implement cementochronology, the analysis of cementum growth, from a chronobiology perspective. Chronobiology, the study of biological rhythms, rests on the premise that the regular rotation of the earth around its central axis and the sun produces two fundamental periodicities to which all life has become adapted. The evolutionary "clock-shop" model posits that circadian clocks govern daily rhythmicity, and circannual clocks provide a seasonal endogenous calendar. We present current theories explaining and interpreting cyclic growth marks observed in hard tissues, especially cementum. Repeated empirical and validation studies are now available to explain cementum's annual/seasonal periodicity, even though specific molecular pathways are still needed. We present our evidence in three parts covering cementum biology, protocols, and anthropological applications and argue that cementochronology with its regular and continuous growth characteristics should have a privileged place among skeletal age indicators.

The circannual rhythm and continuous growth of cementum throughout life have been seen by many researchers as offering an exciting window of potential information of life history recorded in the shape, texture, and chemistry of its increments. A host of studies have thus been presented studying the relationship between these factors and various life history events affecting mammal physiology, most notably pregnancy and parturition. This chapter reviews the literature that has tested this assumption directly, in animals and in humans. Also, we offer theoretical and methodological insights into future advances in cementochronology specifically for identifying and recording these life-history events.