Feeding of prehistoric and historic horses at the eastern Baltic Sea region and western Russia

The early horse management and caretaking practices are often mostly unknown due to a lack of historical documents, particularly in Northern countries. However, the horse care and feeding could have varied among different regions and cultural groups. We studied prehistoric and historic horses from Finland, Estonia, Lithuania and Western Russia to assess the extent of human supplementary feeding practices, to compare regional differences in horse feeding habits and the habitats of wild horses. Feeding of horses could differ in areas with extensive forest cover and historical use of forest pasturing from feeding in more open areas. In addition, less valued working horses could have received less supplementary feeding/less quality feed than the most valued riding horses. We used radiocarbon dating to establish a chronology of the archaeological horse finds and stable isotope analysis of carbon (δ¹³C) and nitrogen (δ¹⁵N) to infer long-term diet. We identified three probable wild horses, as well as one dating back to the period of horse domestication/dispersal. Most samples represented horses from 400–1400 CE (common era). Stable isotope composition of carbon revealed differing isotope ratios between western and eastern samples, implying regionally differing feeding practices (most likely forest pasturing – pasturing in more open areas). We observed high δ¹⁵N values in some horses, indicating that they were likely supplied with manure-fertilized agricultural plants. Lithuanian presumably wild horses lived in a refugium habitat, either in dense forest or in marshland. Overall, we found variable horse caretaking practices in the eastern Baltic Sea region and western Russia.