Fossils, fish and tropical forests: prehistoric human adaptations on the island frontiers of Oceania

Abstract

Oceania is a key region for studying human dispersals, adaptations and interactions with other hominin populations. Although archaeological evidence now reveals occupation of the region by approximately 65–45 000 years ago, its human fossil record, which has the best potential to provide direct insights into ecological adaptations and population relationships, has remained much more elusive. Here, we apply radiocarbon dating and stable isotope approaches to the earliest human remains so far excavated on the islands of Near and Remote Oceania to explore the chronology and diets of the first preserved human individuals to step across these Pacific frontiers. We demonstrate that the oldest human (or indeed hominin) fossil outside of the mainland New Guinea-Aru area dates to approximately 11 800 years ago. Furthermore, although these early sea-faring populations have been associated with a specialized coastal adaptation, we show that Late Pleistocene–Holocene humans living on islands in the Bismarck Archipelago and in Vanuatu display a persistent reliance on interior tropical forest resources. We argue that local tropical habitats, rather than purely coasts or, later, arriving domesticates, should be emphasized in discussions of human diets and cultural practices from the onset of our species' arrival in this part of the world. This article is part of the theme issue ‘Tropical forests in the deep human past’.

Tropical forests in the deep human past

“…In contrast with Africa, Asian tropical forest extent was probably greater throughout the prevailing glacial conditions of the Pleistocene, as low sea levels greatly increased land area and connectivity in Sundaland and Sahul, while the generally maritime climate maintained high rainfall [ 62 ]. Moving into the tropical forests of Wallacea and the Pacific, humans would also have to contend with unique insular tropical ecosystems and the necessity of seafaring (see [ 63 ]).…”

“…Finally, moving out into the Pacific realm, Roberts et al . [ 63 ] present new radiocarbon and stable isotope data from the earliest human remains so far excavated in tropical island settings in Near and Remote Oceania. This is a key region for exploring early maritime crossings, human adaptations to insular and coastal environments, and the possibility of interactions between different hominin species.…”

“…In warm and wet ecosystems where organic preservation is low and sites difficult to find and locate, the traces of human impact on the environment may sometimes be the only evidence of past occupation. Stable isotope analysis of human tooth enamel has also emerged as a means of assessing overall dietary reliance in the face of incomplete plant and animal assemblages [ 38 , 40 , 63 ]. Such sensitive approaches must be combined with traditional archaeological investigations in order to fully appreciate the context of past human engagement with tropical forests.…”

“…This is a key region for exploring early maritime crossings, human adaptations to insular and coastal environments, and the possibility of interactions between different hominin species. Roberts et al [63] show that there is currently a significant gap between the earliest occupation of the portion of Near Oceania beyond the continent of Sahul approximately 45 ka and the oldest human remains from the region approximately 11.8 ka. However, the authors demonstrate that Late Pleistocene-Holocene humans living on islands in the Bismarck Archipelago and Vanuatu had a persistent reliance on tropical forest plants and animals.…”

Assessing Pleistocene–Holocene climatic and environmental change in insular Near Oceania using stable isotope analysis of archaeological fauna

“…in terms of chronology and the nomenclature used to define different ‘phases’) (Specht, 2005). For example, recent data suggest that Pamwak on Manus may have been occupied long before the LGM (Roberts et al , 2022). Nonetheless, such models encapsulate the potential significance of changing subsistence and settlement patterns in the region and raise the question as to their relationship with late‐glacial climate and environmental change.…”