Stable isotope insights (δ¹⁸O, δ¹³C) into cattle and sheep husbandry at Bercy (Paris, France, 4th millennium BC): birth seasonality and winter leaf foddering

Abstract

Bercy is a prehistoric village sited by the Seine river (Paris, France), whose main period of occupation was dated to the very beginning of the 4th millennium BC. The animal subsistence economy relied heavily on cattle husbandry, complemented by other species including sheep. Cattle and sheep isotopic history (δ¹³C, δ¹⁸O) was investigated at the seasonal scale, through sequential sampling in tooth enamel, providing new insights into seasonality of birth and diet. Sheep were lambing in mid-spring, only slightly later than expected from what is observed nowadays in temperate Europe at similar latitude. Cattle were born over a period spanning approximately six months, which was an unexpected result compared with a two to three months calving period in free-ranging cattle populations. The extension of the calving period might have been related to seasonal food supplementation. Some cattle and some sheep fed on a ¹³C-depleted resource in winter, potentially leafy fodder. A direct consequence of an extended calving period would be the availability of cow milk, which would have covered the whole year at Bercy. This is important information in a context where the exploitation of cattle milk by the human community was highly suspected from the demographic management of the herd.

Keywords:

• cattle
• sheep
• carbon and oxygen stable isotope ratios
• tooth enamel
• birth seasonality
• fodder

Yves Lanchon gave access to the faunal material for stable isotope analysis. This research received financial support from the Région Ile de France, a CNRS INSU program ECLIPSE II 2005–2007 (Climatic constraints and development of Neolithic husbandry in Western Europe at the Atlantic/Sub-Boreal boundary (4th millennium BC), dir. M. Balasse and A. Tresset) and a ERC Starting Grant GA 202881 SIANHE (dir. M. Balasse). Stéphanie Bréhard provided us with her expertise for the determination of sheep teeth. We would like to thank Allowen Evin (UMR 7209 CNRS) and Gaël Obein (Laboratoire Commun de Métrologie, LNE-CNAM) for advice on the statistical treatment of data.