New evidence on the earliest domesticated animals and possible small-scale husbandry in Atlantic NW Europe

The study addresses when and how domesticated animals and crops first appeared in the coastal lowlands of Atlantic NW Europe, a region outside the early Neolithic loess belt. Two competing models frame the debate: (1) a gradual, early 5th millennium cal BC transition with significant involvement of indigenous hunter-gatherers (acculturation/cultural diffusion), and (2) a rapid, late 5th millennium transition driven by demic diffusion of incoming farmers. The reliability of early isolated finds (animal bones and cereals) predating 4300/4000 cal BC has been contentious. This paper aims to clarify the timing and nature of early domesticates in the Lower Scheldt basin (NW Belgium) by presenting new radiocarbon dates and multi-isotope evidence from Bazel "Sluis," evaluating whether early domesticates reflect exchange of products/animals or local husbandry, and assessing implications for the Neolithization process.

Previous work identified early domestic animal remains and cereals in northern Germany and the Netherlands (e.g., Ertebølle sites Rosenhof LA 58/83; Dutch Swifterbant sites Hardinxveld, Brandwijk, Schokland), with suggested dates as early as 4700–4450 cal BC. Many of these claims have been challenged on genetic, stratigraphic, and dating grounds, although some remain robust: Mesolithic use of pigs with Near Eastern ancestry (Rosenhof, Poel, 4720–4582 cal BC) and a sheep/goat bone at Hardinxveld (4520–4356 cal BC). Interpretations vary, including hybrid wild–domestic pigs or exchange of live animals (on the hoof) from farmer groups. Evidence for local husbandry in the lowlands before 4300/4000 cal BC has been limited. The Bazel site previously produced carbonized cereal grains, the oldest circa 4800 cal BC, and domesticated animal bones initially dated no earlier than ca. 4300 cal BC; new dates and isotopes now expand this evidence.

Site and context: Bazel "Sluis" is a wetland site on a sandy elevation along a palaeochannel of the Scheldt River. Excellent preservation due to peat and alluvial clays yielded unburnt bones. Two major occupation phases exist: Early/Middle Mesolithic (8th millennium cal BC) and a long phase from the late 6th to mid-4th millennium cal BC (Late Mesolithic, Final Mesolithic/Early Neolithic Swifterbant and Michelsberg). Due to limited sedimentation, materials are intermingled; bones from the early phase are not preserved. Bones derive from a bank-side dump (better preserved) and the top of the sandy elevation (more fragmented, teeth prevalent). Faunal identification: Standard zooarchaeological methods and reference collections were used. Specimens were identified to species where possible; otherwise by size class. Sheep vs. goat distinctions followed Boessneck; cattle vs. aurochs differentiation combined overall size/dimensions and metric comparisons to literature. Pig vs. wild boar could not be reliably distinguished and were excluded from targeted dating; genetic analyses on some domesticated bones were attempted but failed. Radiocarbon dating: Building on four earlier dates, twelve additional bones/teeth (mostly cattle, some sheep/goat) were dated by AMS (KIA, RICH). Collagen extraction followed Longin with acid demineralization, NaOH wash, gelatinization, filtration, and freeze-drying. CO2 was graphitized (Fe catalyst, H2). Results were normalized to δ13C = −25‰, calibrated with IntCal13 using OxCal 4.3 (Sum function). Stable isotope analysis (collagen): δ13C and δ15N of bone/dentine collagen were measured in duplicate using a Thermo Flash EA/HT coupled to a Thermo DeltaV Advantage IRMS. Standards included IAEA-N1, IAEA-C6, and acetanilide; analytical precision ~0.25‰. Tooth enamel isotopes and Sr concentrations: External enamel layers were removed; ~50 mg enamel powder was pre-treated (0.1 M acetic acid) and rinsed. ~15 mg was dissolved for 87Sr/86Sr on a Nu Plasma MC-ICP-MS (ULB), normalized via standard bracketing to 0.710248; blanks negligible; precision reported as 2σ internal error. Sr and Ca concentrations were measured by sector field ICP-MS (VUB), normalized to 40% Ca; precision better than 5%. Enamel carbonate δ13C and δ18O were measured on a Nu Perspective IRMS with NuCarb device; precision ±0.25‰. Data analysis: Calibrated age distributions were summarized as summed probability distributions for all dated materials, domesticated herbivores, wild herbivores, and charred cereals to assess occupation continuity and temporal clustering. Collagen and enamel isotope data were compared to contemporaneous datasets from loess regions in France and Germany and to Bazel wild herbivores to infer provenance and husbandry practices.

• Taxa identified: Domesticated species include cattle (Bos primigenius f. taurus), pig (Sus scrofa f. domestica), sheep (Ovis ammon f. aries), goat (Capra aegagrus f. hircus), and dog; wild species include aurochs, red deer, roe deer, hare, beaver, and wild boar. Cattle dominate identified mammal bones (42.6%), sheep/goat constitute 5.1%, and pig/wild boar 21.7%.
• Skeletal representation: Cattle assemblage shows over-representation of horncores and loose teeth; sheep/goat remains include cranial elements, a calcaneum, tibia, vertebrae; age indicators in sheep/goat span subadult to adult.
• Radiocarbon chronology: Two distinct clusters for dated domesticated herbivores (n=16): (1) ca. 4800–4500 cal BC (n=6) and (2) ca. 4300–3800 cal BC (n=10), with one outlier at 3650–3525 cal BC. A gap in the third quarter of the 5th millennium likely reflects fluvial erosion bias, not occupational hiatus (cereal dates show continuity). The oldest dated cattle metacarpal (RICH-26274, 5852±30 BP) calibrates to 4795–4620 cal BC (2σ). Oldest cluster includes a nearly complete goat horncore and a sheep/goat cranium fragment, unequivocally domesticated.
• Morphometrics: Two early-cluster cattle metacarpals (proximal widths 59.46 and 58.02 mm) align with domesticated cattle metrics from contemporaneous Neolithic cultures (e.g., Cerny), distinct from aurochs.
• Collagen isotopes: Domesticated cattle and sheep/goat collagen δ13C ranges −24.6 to −23.1‰ (mean −23.7‰); δ15N 4.8 to 6.6‰ (mean 5.6‰). Slight δ13C increase (~0.4‰) from oldest to youngest cluster. Dentine collagen (younger cluster) shows slightly higher values (δ13C −23.2 to −22.5‰; δ15N 5.2 to 6.8‰).
• Enamel isotopes and Sr: Cattle enamel 87Sr/86Sr = 0.7094–0.7121; Sr concentrations 187–250 ppm. Enamel carbonate δ13C −15.3 to −12.8‰; δ18O −7.5 to −4.6‰. Variability suggests animals did not graze in a single uniform area; some δ18O values match modern Scheldt basin horses, others align with coastal salt-marsh sheep values.
• Comparative isotopes: Bazel domesticates have generally lower δ13C and δ15N than many early/middle Neolithic loess sites in northern France/Germany, but match Bazel wild herbivores (especially aurochs), implying similar environments.
• Integration with cereals: The earliest domesticated animal dates are synchronous with earliest cereals at Bazel (~4800 cal BC), placing domesticates within reach of local hunter-gatherers well before 4300/4000 cal BC.
• Interpretation: Evidence supports early introduction of domestic sheep/goat and likely cattle in the Lower Scheldt basin by ca. 4800/4600 cal BC and indicates probable small-scale local husbandry by at least ca. 4300 cal BC, potentially earlier.

The findings directly address the timing and nature of early domesticates north of the agro-pastoral frontier. Radiocarbon and isotope data from Bazel demonstrate that domestic sheep/goat and likely cattle were present in the Lower Scheldt basin by 4800–4600 cal BC, contemporaneous with the earliest cereals, thereby supporting a gradual Neolithization model with sustained forager–farmer interaction. Collagen isotope values for Bazel domesticates differ from many loess-region datasets but mirror local wild herbivores, suggesting animals lived and fed in similar environments to local wild fauna and pointing toward local husbandry rather than exclusive importation. The Sr and O isotope variability in cattle enamel indicates use of different grazing areas and/or diverse local environments (e.g., coversands, saltmarshes, peaty marshlands within ~10 km), consistent with small-scale, flexible herding strategies. A slight increase in δ13C from the early to late 5th millennium may reflect environmental change (transition from dense alder carr to more open tidal/alluvial forests due to rising sea influence) and/or seasonal leaf-foddering versus open grazing (canopy effect), aligning with regional archaeobotanical evidence (ivy and mistletoe fodder). Cultural indicators (lithic technology shifts, local pottery production) align temporally with these biological signals, underscoring knowledge transfer and direct involvement of farmer-herders with local groups. Overall, the results argue that early domesticates in the lowlands were not solely passing exchange items but part of emerging local stockkeeping practices, leading toward a mixed economy prior to full agricultural adoption.

The study provides robust evidence for domesticated sheep/goat and most likely cattle in the Lower Scheldt basin from ca. 4800/4600 cal BC, supporting a long-term, gradual Neolithization in Atlantic NW Europe. Isotope data, while limited, favor the presence of small-scale local husbandry from the outset, implying intensive, sustained forager–farmer interactions and knowledge transmission during the first half of the 5th millennium cal BC. This period marks a substitution/introduction phase that set the stage for a fully agrarian society by around 4000 cal BC, possibly accelerated by environmental changes (tidal flooding improving agricultural conditions). Future research should expand isotope baselines (notably bioavailable Sr in Belgium), increase sample sizes across taxa (including pigs), and integrate further genetic analyses to refine provenance and husbandry interpretations.

• Mixed palimpsest contexts complicate precise cultural attribution; complete separation of occupation phases is not possible.
• Identification issues for pig vs. wild boar precluded targeted dating of suid remains; genetic attempts on some domesticated bones failed.
• Sample sizes for isotopic analyses, especially enamel Sr/O/C on cattle and collagen on sheep/goat, are small, limiting statistical power.
• A gap in bone radiocarbon distributions (third quarter of the 5th millennium) likely reflects fluvial erosion bias of the bone-bearing strata.
• Lack of a detailed biologically available strontium isotope baseline for Belgium currently limits provenance resolution; interpretations should be revisited as baselines improve.
• Limited comparative isotope datasets from the nearby Belgian loess area constrain regional sourcing assessments.