The Eemian Interglacial: When Northern Europe Was Warmer Than Today
Around 123,000 years ago, during what geologists call the Eemian interglacial (Marine Isotope Stage 5e), temperatures in northern Europe exceeded current averages by 2 to 3 degrees Celsius. The English Channel was an inland sea, lions and hippopotamuses roamed the banks of the Thames, and dense forests of oak, lime, and hornbeam covered regions that today are agricultural landscapes. It was in this radically different climatic context that NeanderthalsNeanderthalsA fossil humanity of Eurasia, robust and cold-adapted, extinct around 40,000 years before present.→ inhabited the Somme valley in what is now northern France.
A study led by Julie Dabkowski (CNRS) and colleagues, published in The Conversation and deposited on HAL (hal-04736018), sheds new light on the environmental conditions in which Neanderthals lived 123,000 years ago at the Caours site in Picardy.1 Their conclusions challenge a persistent stereotype: that of a Neanderthal exclusively adapted to the cold steppes of the ice age.
Caours: A Calcareous Tufa That Speaks for the Forest
The Caours site in the Somme department is characterised by a deposit of calcareous tufa - a porous rock formed by the precipitation of calcium carbonate in CO2-enriched springs - some three to four metres thick. Such tufas form exclusively in cool, humid, vegetation-rich environments, making them remarkable palaeoenvironmental archives.
Researchers analysed fossil mollusc assemblages (malacology) extracted from these sediments. The snail and bivalve species identified serve as biological thermometers and hygrometers: each species has well-documented narrow climatic tolerances. At Caours, the malacological composition unambiguously indicates the presence of a dense, cool, humid temperate forest with abundant undergrowth. This is not the cold steppeSteppeA vast semi-arid, treeless grassland of Eurasia, suited to nomadic herding and the horse; a corridor for the movement of peoples and technologies in later prehistory.→ landscape commonly associated with Neanderthals - it is a forest comparable to the woodlands of present-day western Europe.1
These conclusions are reinforced by the presence in the sediments of bones from red deer, fallow deer, wild boar, and Merck's rhinoceros - all forest or woodland-edge animals. Several of these bones bear characteristic cut marks attesting to systematic carcass processing by Neanderthals. FlintFlintA hard, brittle siliceous rock, knapped by prehistoric people to produce blades, points and sharp tools.→ tools of MousterianMousterianThe stone-tool industry typical of Neanderthals, based on the Levallois flaking technique.→ workmanship complete the picture of intensive human occupation of the site.
A More Adaptable Neanderthal Than Previously Thought
These findings are part of a broader scientific movement to reexamine Neanderthal behavioural and ecological profiles. Long portrayed as cold-weather specialists tightly dependent on glacial steppe fauna, Neanderthals are progressively emerging as remarkably adaptable hominins capable of exploiting environments as contrasted as the cold steppes of central Europe and the temperate forests of the Atlantic coast.
Researchers have identified two additional Eemian sites providing similar evidence in northern France: Waziers in the Nord department and Resson in the Marne. This geographic recurrence is significant: it suggests that the Somme valley and its surroundings constituted a corridor frequented by Neanderthals during warm periods, allowing them to move northward in step with the expansion of temperate forests.
These discoveries invite a rethinking of the concept of "adaptation" in Neanderthals: rather than a species narrowly specialised in a single biome, what emerges is a portrait of a species capable of adjusting its subsistence strategies, hunting techniques, and probably its social organisation according to the resources available in very different environments.2
No comments yet. Be the first.