For the past eight millennia, the physical dimensions of both wild and domestic animals inhabiting the northwestern Mediterranean region have undergone remarkable transformations. Recent research reveals a complex interplay between environmental dynamics and human interventions that have distinctly shaped these evolutionary trajectories. An international team of scientists from the French National Centre for Scientific Research (CNRS), along with collaborators in archaeology and climate modeling, have meticulously analyzed over 80,000 bone measurements from archaeological sites in southern France, unveiling an unprecedented long-term narrative about animal morphology. Their findings, published in the prestigious journal Proceedings of the National Academy of Sciences, emphasize how anthropogenic factors in just the last thousand years have profoundly diverged the size trends of wild and domestic fauna.
Throughout most of the last 7,000 years, wild and domesticated species exhibited synchronous size changes, evolving in a closely intertwined manner influenced predominantly by shifting climatic and environmental conditions. This evolutionary synchrony hints at a shared adaptive response to external pressures, such as changes in temperature, vegetation patterns, and ecosystem structure, rather than isolated selective breeding or hunting pressures. The interconnectedness of wild and domestic animal size during this extended period underscores the dominant role that natural factors once played in sculpting the physical attributes of these populations.
However, the onset of the Middle Ages marks a pivotal moment in this long-standing balance. Human influence intensified dramatically, manifesting through expansive agricultural practices, landscape modifications, and systematic animal management. Domestic species such as sheep, goats, pigs, cattle, chickens, and rabbits began exhibiting continuous and notable increases in body size. This enlargement is attributed not merely to human predation or environmental changes but fundamentally to deliberate selective breeding aimed at enhancing productivity, a hallmark of burgeoning agrarian societies seeking economic optimization.
Conversely, wild animal populations including species like deer, hares, and foxes followed a contrasting path, exhibiting a consistent reduction in body size across the same period. This contraction is largely explained by intensified hunting pressures and habitat fragmentation due to the expansion of human settlements, deforestation, and land conversion. The shrinking natural environments resulted in population stressors and altered ecological niches, catalyzing evolutionary pressures favoring smaller body sizes possibly linked to resource scarcity or adaptive strategies under human-induced environmental constraints.
The unraveling of these divergent trends was made feasible by combining vast archaeological datasets with cutting-edge paleoenvironmental reconstructions. By integrating bone measurements with paleoclimate proxies and archaeological records obtained over three decades, researchers could discern correlations between human societal shifts and morphological adaptations in animals. This interdisciplinary approach bridges biological anthropology, archaeology, and climate science, epitomizing the synergy required to understand anthropogenic impacts on evolutionary timescales.
The extensive dataset drawn from 311 archaeological sites also reveals a temporal gradient in the divergence between wild and domestic body sizes. Prior to one millennium ago, the differences were minimal and changes mirrored one another closely. Post that period, a clear deviation emerges, highlighting the intensification of human-driven selection mechanisms and land use changes. This divergence provides a compelling historical context for ongoing concerns about biodiversity loss, habitat fragmentation, and the implications of human stewardship on animal genetic diversity and morphology.
Selective breeding practices during the last thousand years were powered by emerging agricultural societies’ goals to maximize meat, wool, milk, and labor yields from domestic species. This targeted human intervention blurred the lines between natural evolution and anthropogenic selection. Enhancements in husbandry techniques, improvement in animal nutrition, and the introduction of breed standards catalyzed rapid size increases, marking a new era in mammalian evolution closely tied to human economy and culture.
In contrast, wild species bore the brunt of expanding human colonization in terms of habitat degradation and hunting pressures. The shrinking body sizes observed are believed to be adaptive responses to increased mortality risks, reduced availability of resources, and fragmented habitats. Smaller body size in mammals has been theorized to confer advantages in such disturbed environments, including shorter reproductive cycles and lower energy requirements, framing this size reduction as a survival strategy amid acute anthropogenic challenges.
A striking aspect of this research is the temporal resolution and geographical breadth of the analysis. The study’s reliance on an exceptionally large and calibrated osteometric database makes it one of the most comprehensive explorations of animal size evolution over millennia. Southern France, with its rich archaeological record and detailed paleoenvironmental archives, serves as an ideal natural laboratory, capturing the intricate dance between humans, animals, and climate across epochs.
Beyond clarifying historical evolution, these insights offer a crucial perspective on contemporary conservation and animal breeding. Understanding how human activities have shaped animal morphology historically provides a framework to anticipate future responses to ongoing environmental changes and human pressures. It underscores the importance of integrating evolutionary history in sustainable animal management and biodiversity conservation strategies.
Importantly, the researchers emphasize that while selective breeding has predominantly influenced domestic animals’ increasing size, the culling and habitat stresses affecting wild species represent indirect but potent facets of human impact. This complex narrative broadens the discourse on anthropogenic effects, moving beyond simplistic notions of exploitation to encompass nuanced ecological and evolutionary dynamics.
In conclusion, this groundbreaking study reshapes our understanding of human-environment-animal interactions over extensive temporal scales. It highlights the profound divergence in evolutionary pathways between wild and domestic animals forged under escalating human influence in the last millennium. Such findings accentuate the enduring imprint of humanity not only on cultural and social development but fundamentally on biological and ecological systems, offering a vital lens through which to view both the past and future of animal populations.
Subject of Research: Animals
Article Title: 8,000 years of wild and domestic animal body size data reveal long-term synchrony and recent divergence due to intensified human impact
News Publication Date: 2-Sep-2025
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DOI Link
Image Credits: © Allowen Evin
Keywords: animal morphology, evolutionary biology, domestication, anthropogenic impact, selective breeding, body size evolution, paleoenvironment, archaeological study, human-wildlife interaction, habitat fragmentation
