The Levant witnessed the early domestication of livestock such as cattle, pigs, and caprines -sheep and goats-, known as the “domestic triad”. Research has convincingly demonstrated that one of the reasons, along with societal developments and population expansion, for plant and animal domestication lies in the ecological constraints prehistoric human populations endured. Climate change necessitated adaptations in cultural and behavioural practices within these ancient societies: from being hunter-gatherers to pastoralists and cultivators, from nomadism to sedentarism, and from small human groups to large populations. Animal domestication is thought to coincide with the end of a cooling period in this region, the Younger Dryas (12,900-11,500 y. BCE). The subsequent onset of warmer conditions favoured the adoption of agriculture and allowed the expansion of pastures to feed the animals. However, the temperature increase led to extensive aridity during the VIIIth mill. BCE.
At the heart of Levantine subsistence economies are sheep, Ovis aries and goats, Capra hircus. They were domesticated in the Northern Levant and Zagros mountains around the XIIth millennium BCE from their wild ancestors O. orientalis and C. aegragus. Caprines have been exploited by human groups for their meat, wool and milk ever since. At first, the association of domesticated caprines with wild faunas (especially wild bovid species) in archaeological assemblages suggests their slow incorporation into hunter-gatherer societies. In this region, the continuous association of domesticated caprines with hunted gazelles, and other small (wild) ungulate species, blur the interpretation of past subsistence strategies and restricts comparative species consumption analysis. Gazelle species, as long as caprines, have different climatic tolerances and are thus expected to contribute to human diet in different proportion, depending on climatic conditions. But in arid and semi-arid environments the notably poor preservation and high fragmentation of skeletal remains leads to difficulties in species identification using “classical” zooarchaeological methods applying comparative anatomy. It is therefore unclear to what extent climatic changes imposed constraints on these past human groups’ subsistence strategies.
The use of molecular methods is hence of particular relevance since it can assist in the species identification of faunal remains. At higher latitudes, ancient DNA (aDNA) is often the molecule of choice, but it degrades rapidly in arid and semi-arid environments. Ancient protein (palaeoproteomics) has demonstrated its potential for the retrieval of biological information from archaeological material. The use of palaeoproteomics in arid and semi-arid environments contexts is currently limited to a few studies but is increasingly of interest, especially when it concerns gazelles and caprines distinction in faunal assemblages. Minimally destructive and comparatively cheap, the method can allow better insights on food consumption, even when applied to highly degraded bone fragments. However, due to the novelty of the field and the low economical interest for gazelle species from arid environments, there is only restricted access to reference protein sequences for several relevant species, making their identification in the archaeological record through proteomic analysis currently impossible. The relative contribution of sheep, goats and several non-domestic species, such as gazelles, in the Levant, is of particular importance to infer human responses to climate constraints. Due to comparatively high fragmentation rates, however, such quantitative data is largely lacking for the region. Moreover, modern herd management involves strict sex-driven culling patterns. Proteomics could provide insights into the development of such practices during the transition to herding by providing sex-ratio estimates for archaeological assemblages.
Human societies are currently facing a variety of consequences due to climate change and need to adapt in order to protect both the Earth and its inhabitants. One of the major challenges pertains to food production, including the adaptability of animal breeds to hotter climates that are increasingly lacking available water. Looking into the past could help us face these challenges. Studying past human-animal relationships not only provides information on subsistence strategies, but also covers a wide range of ancient human behaviours, from culinary practices to responses to ecological constraints. Located in one of the currently most challenging environmental regions, the ICARHUS: Identifying Constraints: Ancient protein characterisation to Reveal past Human Subsistence adaptations to climate change project aims to reveal past Levantine human societies adaptation to environmental pressures. It will do so by applying cutting-edge ancient protein research and integrating this with existing zooarchaeological datasets for the region.
