Primitive humans first migrate to the Indian subcontinent between 400,000 and 200,000 BCE; some of them possibly sail to southern India from eastern Africa.

Australia is possibly occupied by at least 174,000 BCE (a date suggested by archaeological fieldwork in Western Australia’s Kimberley district).

The beginning of the last Ice Age is conventionally dated at about 120,000 BCE.

The Eemian, an interglacial period which begins about one hundred and thirty thousand years ago and ends about one hundred and fourteen thousand years ago, is the second-to-latest interglacial period of the current Ice Age, the most recent being the Holocene which extends to the present day.

The prevailing Eemian climate is believed to have been about as stable as that of the Holocene.

Changes in the earth's orbital parameters from today (greater obliquity and eccentricity, and perihelion), known as the Milankovitch cycle, probably lead to greater seasonal temperature variations in the Northern Hemisphere, although global annual mean temperatures are probably similar to those of the Holocene.

The warmest peak of the Eemian is around one hundred and twenty-five thousand years ago, when forests reach as far north as North Cape (which is now tundra) in northern Norway well above the Arctic Circle.

Hardwood trees like hazel and oak grow as far north as Oulu, Finland.

At the peak of the Eemian, the northern hemisphere winters are generally warmer and wetter than now, though some areas are actually slightly cooler than today.

The hippopotamus is distributed as far north as the rivers Rhine and Thames.

Trees grow as far north as southern Baffin Island in the Canadian Arctic Archipelago instead of only as far north as Kuujjuaq in northern Quebec, and the prairie-forest boundary in the Great Plains of the United States lies further west—near Lubbock, Texas, instead of near Dallas, Texas, where the boundary now exists.

Sea level at peak is probably four to six meters (thirteen to twenty feet) higher than today (references in Overpeck et al., 2006), with much of this extra water coming from Greenland but some likely to have come from Antarctica.

Global mean sea surface temperatures are thought to have been higher than in the Holocene, but not by enough to explain the rise in sea level through thermal expansion alone, and so melting of polar ice caps must also have occurred.

Because of the sea level drop since the Eemian, exposed fossil coral reefs are common in the tropics, especially in the Caribbean and along the Red Sea coastlines.

These reefs often contain internal erosion surfaces showing significant sea level instability during the Eemian.

A 2007 study found evidence that the Greenland ice core site Dye 3 was glaciated during the Eemian, which implies that Greenland could have contributed at most two meters (6.6 feet) to sea level rise.

Scandinavia was an island due to the inundation of vast areas of northern Europe and the West Siberian Plain.

Given that the shorelines of the islands of the present are at this time several feet higher, humans of this epoch must have used boats: the large island of Crete in the Aegean basin is settled as early as 128,000 BCE, during the Middle Paleolithic age.

The period closes as temperatures steadily fall to conditions cooler and drier than the present, with four hundred and sixty-eight-year long aridity pulse in central Europe, and by one hundred and fourteen thousand years before the present, a glacial era has returned.

As humans develop more advanced skills and techniques, evidence of early construction begins to emerge.

Fossil remains of Cro-Magnons, Neanderthals, and other Homo sapiens subspecies have been found alongside foundation stones and stone pavements arranged in the shape of houses, suggesting a shift toward settled lifestyles and increasing social stratification.

In addition to building on land, early humans also develop seafaring technology. The proto-Australians appear to be the first known people to cross open water to an unseen shore, ultimately peopling Australia—a remarkable achievement in early maritime exploration.

Around 55,000 years ago, global weather patterns begin to fluctuate dramatically, shifting from extreme cold to milder conditions and back within just a few decades.

By 50,000 years ago, the Wisconsin glaciation (known in Europe as the Würm glaciation) is well advanced. Expanding ice sheets in North America and Europe push climatic zones southward, transforming the temperate regions of Europe and North America into Arctic tundra-like landscapes. Meanwhile, rain bands typical of temperate zones shift south, reaching as far as northern Africa.

Neanderthals and Climate Adaptation

The Neanderthals, well adapted to cold climates with their barrel chests and stocky limbs, are better suited than Cro-Magnons to retain body heat. However, the rapid and unpredictable climate fluctuations cause ecological upheavals, replacing familiar plants and animals within a single lifetime—a shift to which Neanderthals struggle to adapt.

One major challenge is the replacement of forests by grasslands during the Mousterian Pluvial, an effect of the last Ice Age’s climatic shifts. This change disrupts the Neanderthals’ ambush-based hunting techniques, making it harder for them to secure food. As a result, large numbers of Neanderthals likely perish due to food scarcity and environmental stress, with the crisis peaking around 30,000 years ago.

Neanderthal Burial and Final Strongholds

Despite their decline, Neanderthals appear to be the first humans to intentionally bury their dead, often in simple graves. The last known traces of Mousterian culture, though lacking human remains, have been discovered at Gorham’s Cave on Gibraltar’s remote south-facing coast, dating between 30,000 and 24,500 years ago.

Possible Scenarios for Neanderthal Extinction

Several hypotheses attempt to explain the disappearance of the Neanderthals from the fossil record around 25,000 years ago:

1. Complete Extinction and Replacement: Neanderthals were a separate species from modern humans and became extinct due to climate change and/or competition with Homo sapiens, who expanded into their territories starting around 80,000 years ago. Anthropologist Jared Diamond suggests that violent conflict and displacement played a role in their demise.

2. Interbreeding and Absorption: Neanderthals were a contemporary subspecies that interbred with modern humans, gradually disappearing through genetic absorption.

3. Volcanic Catastrophe: A Campanian Ignimbrite super-eruption around 40,000 years ago, followed by a second eruption a few thousand years later, may have severely impacted Neanderthal populations. Evidence from Mezmaiskaya Cave in the Caucasus Mountains of southern Russia supports this theory, with mitochondrial DNA (mtDNA) analysis showing a distinct Neanderthal lineage separate from modern humans.

Energy Needs and Survival Challenges

Neanderthals had higher caloric requirements than any other known human species. They required 100 to 350 more calories per day than an anatomically modern human male (68.5 kg) or female (59.2 kg). This higher energy demand may have made them especially vulnerable when food sources became scarce, further contributing to their extinction.

Ultimately, by 25,000 years ago, Neanderthals disappear from the fossil record, leaving behind traces of their culture—but no direct descendants in the modern human genetic lineage.

Southern Indian Ocean (49,293–28,578 BCE): Upper Pleistocene I — Glacial Frontiers and the Subantarctic Living Sea

Geographic & Environmental Context

During the height of the last Ice Age, the Southern Indian Ocean world—composed of the Southeast Indian Ocean subregion (Kerguelen east of 70°E, Heard, and McDonald Islands) and the Southwest Indian Ocean subregion(western Kerguelen, the Îsles Crozet, and Prince Edward–Marion Islands)—stood as a scattered constellation of volcanic outposts astride the circumpolar current.

Together, these two subregions formed the northern ramparts of Antarctica’s climatic realm: bleak, wind-lashed, yet biologically exuberant. Their high plateaus and coastal shelves were carved by ice and pummeled by the Southern Ocean’s furious westerlies.  Kerguelen, the “Great Southern Land” of the subantarctic, spanned nearly 7,000 square miles of basaltic uplands, glaciers, and fjorded coasts—dwarfing its neighbors. To the west, the Crozet and Prince Edward groups rose as serrated volcanic cones; to the east, Heard and McDonald smoldered on the oceanic horizon. Sea levels 60–90 m lower than today broadened their near-shore benches, but their cliffs and mountains ensured that even exposed shelves were narrow.

Climate & Environmental Shifts

Throughout this span, the Last Glacial Maximum gathered strength.

• Atmosphere & Temperature: Mean annual temperatures were several degrees colder than today, and precipitation fell mostly as snow. Ice caps mantled Kerguelen’s highlands and the summits of Heard and Crozet.

• Winds & Currents: The westerly storm belt intensified; katabatic outflow from Antarctica sharpened the pressure gradient, amplifying the “roaring forties” and “furious fifties.”

• Ocean Systems: The Antarctic Circumpolar Current (ACC) tightened around the islands, churning nutrient-rich upwellings that fueled one of Earth’s great marine food webs.

• Sea Level: Lower global sea level expanded intertidal zones and ice-free headlands but did little to change the islands’ rugged relief.

The result was an environment at once extreme and thriving—a cold oceanic oasis in which ice, wind, and water sustained a chain of life from krill to whale.

Ecosystems & Biotic Communities

Though uninhabited by humans, these islands pulsed with ecological energy.

• Terrestrial life: Sparse subantarctic tundra—mosses, lichens, cushion plants, and graminoids—colonized lee slopes and moraines. On Kerguelen’s western plateaus and Heard’s lower benches, periglacial soils nurtured mats of hardy vegetation that trapped moisture and nitrogen from seabird guano.

• Avifauna:  Albatrosses, petrels, skuas, and penguins established immense rookeries, their cycles governed by ice advance and retreat.

• Marine mammals:  Seals and elephant seals hauled out on the few ice-free beaches; whales traced annual feeding migrations through the ACC’s plankton blooms.

• Marine productivity: Krill, squid, and small pelagic fish flourished in cold upwelling zones, knitting together a trans-oceanic ecosystem that linked Antarctica, Africa, and Australasia.

These biological systems recycled nutrients with astonishing efficiency; seabird guano and seal carcasses fertilized soils, and winds redistributed minerals across the ocean surface—an unbroken loop of energy long before any human witness.

Human Absence and Global Context

Elsewhere across the planet, Upper Paleolithic peoples perfected blade industries, tailored clothing, and art traditions, but no seafarers had ventured this far south. The subantarctic islands lay well beyond the reach of any Pleistocene navigation system. Their extreme latitude, relentless weather, and lack of fuel or timber would have defeated even the most adaptable hunter-gatherers.

Their absence, however, highlights a global contrast: while Eurasian and African foragers filled temperate landscapes with symbols and settlements, the Southern Indian Ocean remained the great unpeopled wilderness, its only networks those of wind, current, and migration.

Movement & Interaction Corridors

Even without humans, the region was laced with biological highways:

• The ACC carried nutrients and drifting plankton eastward around the world, feeding a continuous belt of marine life.

• Migratory whales and seabirds followed these currents seasonally, moving between Antarctic feeding grounds and temperate breeding sites.

• The islands themselves acted as stepping-stones for non-human travelers—rookeries, haul-outs, and rest sites—linking ecosystems thousands of kilometers apart.

These corridors, carved by wind and current, pre-figured the oceanic routes that human mariners would one day exploit.

Symbolic and Conceptual Dimensions

To the Ice-Age imagination, had these lands been known, they would have represented the edge of the habitable world—a mythic margin where ocean, ice, and sky merged. In reality they lay beyond any cultural horizon, silent witnesses to global climatic drama, unmarked by tools or fire.

Environmental Adaptation & Resilience

Across glacial cycles, these ecosystems displayed remarkable resilience:

• Vegetation persisted in sheltered micro-refugia, recolonizing freshly deglaciated ground after each cold surge.

• Seabirds and seals adjusted breeding sites in rhythm with ice extent.

• Nutrient cycling remained intact through redundancy: if one rookery failed, others thrived along the current.

This flexibility forged an enduring ecological template that would persist into the Holocene and still defines the subantarctic today.

Transition Toward the Glacial Maximum

By 28,578 BCE, glaciers on Kerguelen and Heard had reached their broadest limits, and sea ice brushed the northern edge of the ACC. Yet life endured in astonishing abundance.

The Southern Indian Ocean, though untouched by humans, was already a complete, self-regulating world—a chain of volcanic fortresses girdling the planet’s coldest sea. Its twin subregions, Southeast and Southwest Indian Ocean, illustrate precisely the principle that unites The Twelve Worlds: even where no people walked, each subregion lived as its own coherent ecology, bound more closely to kindred zones across oceans than to any continental neighbor. When humanity finally reached these latitudes, the template for adaptation—ice, wind, nutrient, and endurance—was already written in the land itself.

Southeast Indian Ocean (49,293–28,578 BCE): Subantarctic Islands in the Ice Age

Geographic & Environmental Context

The subregion of Southeast Indian Ocean includes Kerguelen east of 70°E and Heard Island and McDonald Islands. These remote volcanic islands rise from the southern Indian Ocean far below the subtropical belt, edging into the subantarctic climatic zone. Kerguelen forms the largest landmass, with its basaltic plateaus, glacial valleys, and fjord-like inlets. Heard Island and the tiny McDonald group lie further east, dominated by the active stratovolcano Big Ben on Heard and barren rocky islets in the McDonalds. Rugged coasts, strong currents, and exposure to prevailing westerlies made these lands biologically and climatically distinct from equatorial or continental environments.

Climate & Environmental Shifts

During this Upper Paleolithic age, global sea levels were 60–90 meters lower than today, reflecting the Last Glacial Maximum’s approach. The islands’ coasts were broader, though steep cliffs and volcanic forms kept much of the shoreline dramatic. The climate was colder, windier, and drier, with glaciers expanding across Kerguelen’s uplands and icefields growing around Big Ben. Snow and ice accumulation carved valleys and extended tongues of ice to the sea. The surrounding Southern Ocean was cooler, nutrient-rich, and dynamic, sustaining upwellings that intensified productivity of marine ecosystems.

Subsistence & Settlement

No humans had yet arrived; these islands remained untouched by people until the modern era. Yet ecosystems flourished. Subantarctic tundra vegetation—mosses, lichens, cushion plants, and grasses—covered exposed surfaces. Freshwater lakes and meltwater streams hosted hardy invertebrates. The seas teemed with krill, fish, and squid, supporting colonies of seabirds and seals. Penguins likely ranged widely across the Southern Ocean during this period, using ice-free coasts for rookeries in warmer interludes. These animal communities created ecological patterns of nutrient cycling and guano fertilization that shaped the islands’ soils long before human presence.

Technology & Material Culture

Though humans had no presence here, this period corresponds globally to advances in Upper Paleolithic stone industries—blade technologies, bone tools, and art traditions in other regions. If transoceanic voyaging had improbably reached these latitudes (something for which there is no evidence), survival would have required mastery of cold-weather adaptations: sewn clothing, sea mammal hunting, and ocean-going craft. The absence of such settlement highlights the remoteness and environmental extremity of the Southeast Indian Ocean islands compared with other subantarctic or continental zones.

Movement & Interaction Corridors

The islands lay within the great circumpolar circulation of winds and currents—the roaring forties and furious fifties. Oceanic systems here acted as a conveyor belt for nutrients and migrating species. Marine mammals such as seals, sea lions, and whales followed seasonal routes past Kerguelen and Heard, feeding on the plankton-rich waters. Seabirds traversed vast distances, linking the islands ecologically to Antarctica, Africa, and Australasia. Although no humans traveled these corridors at this time, the patterns they would later rely on—migratory pathways, productive fisheries—were already established.

Cultural & Symbolic Expressions

There were no cultural expressions tied to these islands in this age. Symbolic activity was flourishing elsewhere: cave paintings in Europe, ritual burials in Asia, and ornaments in Africa. If known, such remote islands might have carried a liminal symbolic weight as places beyond the margins of human habitation. But in this period, they remained outside the human imaginative sphere.

Environmental Adaptation & Resilience

Ecosystems on Kerguelen and Heard demonstrated resilience to glacial fluctuations. Plant life endured in sheltered microclimates, retreating and re-expanding as glaciers advanced and retreated. Bird and seal populations adapted to shifting ice fronts, relocating rookeries and haul-out sites. The islands thus exemplified how subantarctic ecologies reorganize under climatic stress, laying groundwork for the resilience patterns observed into the Holocene.

Transition

By 28,578 BCE, the glacial maximum was approaching, with ice sheets at their most extensive. The Southeast Indian Ocean islands stood as icy outposts, ecologically vibrant but humanly unvisited. Their landscapes were already etched by glaciers, storms, and ocean swells—patterns that would persist until humans finally encountered them millennia later.

Andamanasia (49,293 – 28,578 BCE) Upper Pleistocene I — Ice-Age Shelves, Reef Flats, and Island Forest Refugia

Geographic and Environmental Context

Andamanasia encompasses:

• Andaman Islands (North, Middle, South Andaman) and Nicobar Islands.

• Aceh in northern Sumatra, with nearby islands (Simeulue, Nias, Batu, Mentawai).

• The Cocos (Keeling) Islands.

• The Preparis, Coco, and Little Coco Islands (off Myanmar).
  
  Anchors: North–South Andaman coasts and reefs, Nicobar Great Channel, Aceh’s Weh Island and Lhokseumawe–Banda Aceh corridor, Simeulue–Nias–Mentawai arc, Preparis/Coco islets, Cocos (Keeling) lagoon.

• Sea level ↓ ~100 m: Sunda Shelf largely exposed, connecting Sumatra to mainland SE Asia; Andamans/Nicobars remained island chains but closer to coastlines.

• Islands: forested Andamans; Nicobars with mangrove–reef systems; offshore islands (Cocos, Preparis) exposed limestone flats.

Climate & Environmental Shifts

• Glacial maximum: cooler SSTs, stronger winter monsoon winds; rainfall suppressed, but coastal mangroves and refugia persisted.

Subsistence & Settlement

• Likely unpeopled yet, though possible transient visits from early coastal voyagers hugging Sunda margins.

• Rich seabird/turtle rookeries, mangrove crabs, and reef fish provided high productivity if reached.

Technology & Material Culture

• Not directly evidenced, but contemporaneous SE Asian foragers used flake/microblade toolkits; dugouts or bamboo rafts possible for coastal movement.

Movement & Interaction Corridors

• Sunda coastal highway skirted Nicobar–Andaman arc; exposed shelf meant short crossings from Sumatra → Nicobars → Andamans.

Cultural & Symbolic Expressions

• None directly known; symbolic life inferred from mainland contexts (ochre, ornaments).

Environmental Adaptation & Resilience

• These islands acted as ecological storehouses awaiting human settlement.

Transition

By 28,578 BCE, Andamanasia’s forest–reef mosaics had matured as refugia; human settlement awaited deglaciation.

Southwest Indian Ocean (49,293–28,578 BCE): Volcanic Arcs in the Subantarctic

Geographic & Environmental Context

The subregion of Southwest Indian Ocean includes Kerguelen west of 70°E, the Îsles Crozet, Prince Edward Island, and Marion Island. These islands rise from the southern Indian Ocean in the storm-lashed belt of the subantarctic. Kerguelen’s western expanses formed the largest landmass of the subregion, with basaltic plateaus and glaciated valleys. The Îsles Crozet, scattered volcanic peaks, lay further west; Prince Edward and Marion Islands anchored the subregion’s southwestern corner. All were rugged, volcanic, and isolated, fringed by steep coasts and pummeled by westerly winds.

Climate & Environmental Shifts

This age coincided with the Last Glacial cycle. Sea levels lay 60–90 meters lower, exposing broader coastal shelves but leaving the islands’ steep relief largely unchanged. Temperatures were colder than today, with advancing glaciers on western Kerguelen and high volcanic plateaus across the Crozet and Prince Edward groups. Fierce katabatic winds from Antarctica mingled with circumpolar westerlies, intensifying storm tracks. Ocean waters were cooler, strengthening upwelling systems that enriched marine productivity around these volcanic arcs.

Subsistence & Settlement

Humans had not yet reached these islands. Their ecosystems, however, were rich. Subantarctic tundra vegetation—mosses, lichens, and cushion plants—established themselves in sheltered niches. Seabird colonies, especially petrels and albatrosses, blanketed cliffs, while penguins and seals occupied ice-free shores. Nutrient cycling from guano deposits fertilized soils, creating patches of biological richness amid volcanic barrenness. Offshore, whales, seals, and seabirds traced migratory corridors that linked these islands to Antarctica, southern Africa, and Australasia.

Technology & Material Culture

Although no people lived here, contemporaneous societies elsewhere in the world were advancing Upper Paleolithic toolkits, symbolic traditions, and survival strategies in cold climates. Had humans reached the subantarctic islands, survival would have required highly specialized technologies: insulated clothing, seaworthy vessels, and methods for exploiting marine mammals. The absence of such evidence underlines the extreme isolation of these islands during this age.

Movement & Interaction Corridors

The Southern Ocean circulation swept around these islands, carrying nutrients and sustaining immense food webs. Migrating whales passed seasonally, while seabirds and seals established transoceanic networks of rookeries and feeding grounds. These currents and corridors would one day make the islands strategic for human navigation, but in this age, they were highways only for nonhuman travelers.

Cultural & Symbolic Expressions

No human symbolic activity is tied to the Southwest Indian Ocean islands in this age. Globally, however, human groups were producing art, ornaments, and ritual sites, embedding meaning in landscapes far from these volcanic outposts. The islands themselves remained unknown and unimagined, lying outside the human cultural horizon.

Environmental Adaptation & Resilience

Life on these islands demonstrated resilience to glacial extremes. Vegetation survived in sheltered microhabitats, recolonizing deglaciated areas as climates fluctuated. Seabird and seal populations shifted breeding sites with changing ice coverage. The capacity of these ecosystems to reorganize under climatic stress foreshadowed the adaptive dynamics that would define their later ecological histories.

Transition

By 28,578 BCE, the glacial maximum was intensifying, with ice reaching peak expansion. The Southwest Indian Ocean islands remained untouched by human hands, yet ecologically vital within the subantarctic marine web. These volcanic arcs stood as stark, wind-battered sentinels, their environments shaped by ice, ocean, and storm.

The West Indies (49,293–28,578 BCE): Upper Pleistocene I — Exposed Banks, Reef Arcs, and Island Worlds Without People

Geographic and Environmental Context

During the late Pleistocene, the West Indian archipelagos—stretching from the Bahama banks to Trinidad—were vast, emergent shelves divided into three natural subregions that would later become cultural zones: the Northern, Eastern, and Western West Indies.

• The Northern West Indies comprised the Bahamas and Turks & Caicos banks and the northern coast of Hispaniola.
  Sea levels ~100 m lower than today fused many of the present islands into broad limestone plains dotted with sinkholes and dune fields. The Cibao Valley and the Massif du Nord of Hispaniola formed the rugged southern margin of this shelf sea.

• The Eastern West Indies traced a long volcanic and carbonate arc from Puerto Rico and the Virgin Islands through the Lesser Antilles to Trinidad & Tobago, where the chain met the South American shelf.
  Active volcanoes alternated with uplifted reef terraces and deep inter-island channels shaped by the northeast trades.

• The Western West Indies included Cuba, Jamaica, the Cayman Ridge, and western Hispaniola, flanked by the deep Cayman Trench and the Windward Passage.
  Here, broad banks and narrow straits created a labyrinth of shelves, slopes, and enclosed lagoons fringed by coral and seagrass ecosystems.

These three subregions were already differentiated by geology and oceanography: the Northern banks were broad, flat, and porous; the Eastern arc steep and windward; the Western ridge mountainous and trench-bound. Together they formed the tropical hinge between the Atlantic and Caribbean basins—an archipelago before humanity, alive only with reefs, birds, and tides.

Climate and Environmental Shifts

The interval coincided with the approach to the Last Glacial Maximum, producing climatic contrasts across latitude and elevation:

• Sea level fall of 90–110 m exposed vast carbonate platforms in the Bahamas and Caicos and broadened coastal plains around Cuba and Hispaniola.

• Trade winds intensified as global temperature gradients sharpened, driving upwelling and enhancing nutrient flows along windward coasts.

• Cooler sea-surface temperatures slowed coral accretion but favored calcareous algae, sponges, and mollusks, maintaining high marine productivity.

• Periodic northers and dry seasons reduced rainfall, particularly over the northern and western islands, while volcanic highlands in the east retained moist forests and orographic rainfall.

The result was a gradient from arid limestone plains in the north to humid volcanic slopes in the east, already anticipating the ecological zones that would later support very different island societies.

Biotic Assemblages and Ecological Structure

With no humans yet present, the Pleistocene West Indies were laboratories of insular evolution:

• Seabirds dominated: vast rookeries of boobies, frigatebirds, shearwaters, and petrels nested on cliffs and dunes from the Bahamas to the Grenadines.

• Reptiles and amphibians were diverse, including large lizards and ground-dwelling tortoises on the larger banks.

• Mammals were limited to endemic rodents and small insectivores; ground sloths and monkeys persisted on Cuba and Hispaniola into later millennia.

• Marine ecosystems—reef flats, turtle-nesting beaches, mangrove-lined lagoons—functioned at full productivity, unaltered by hunting or fire.

• Beneath the islands, freshwater lenses formed within porous limestones, supporting vegetation pockets and stabilizing the water table.

These pristine ecologies, organized by rainfall and ocean currents rather than human movement, set the template for all later biological and cultural differentiation in the Caribbean.

Movement and Interaction Corridors

Although uninhabited, the region was threaded by powerful oceanic highways that would later shape both migration and commerce:

• The North Equatorial Current and its offshoot, the Florida Current, swept westward across the Lesser Antilles and northward through the Bahamas toward the Gulf Stream.

• Countercurrents and eddies along the Caribbean side of the arc distributed larvae, seeds, and drifting vegetation between islands, knitting their ecosystems together.

• These same pathways would eventually become the maritime corridors of human voyaging; in this epoch, they served only seabirds and sea turtles, tracing the routes that future canoes would follow.

Cultural and Symbolic Dimensions

No human symbolic system had yet entered this landscape, yet the environment itself encoded rhythms and structures that later peoples would mythologize: the circularity of atolls, the seasonal pulse of trade winds, the nesting cycles of seabirds, the periodic flooding and drying of lagoons.
These were the physical archetypes of later Caribbean cosmologies—worlds of tide and return, absence and reemergence.

Environmental Adaptation and Resilience

In biological terms, the archipelago functioned as a self-balancing triad:

• Northern carbonate banks acted as vast nurseries for marine life, their freshwater lenses and seagrass meadows stabilizing regional nutrient budgets.

• Eastern volcanic islands provided vertical zonation—reef, mangrove, forest—that buffered storms and erosion.

• Western highlands generated sediment and nutrients feeding neighboring shelves.

Interconnected by wind and current, these systems maintained equilibrium without external disturbance. Each island was autonomous yet ecologically interdependent—an early analogue of the inter-island diversity that would later underpin cultural resilience in the peopled Caribbean.

Transition Toward the Last Glacial Maximum

By 28,578 BCE, the West Indies were an archipelago of abundance awaiting discovery.
Emergent banks and volcanic ridges, swept by steady trades, supported some of the most productive reef and seabird ecosystems on Earth.
No human footprints yet marked their dunes, but the stage was set: broad shelves for future navigation, fertile soils for cultivation, and ecological gradients for diversification.
In this epoch, the Caribbean existed as a network of natural worlds, poised—like the other realms of The Twelve Worlds—to become human worlds when the seas rose again.