Homo sapiens in Island Southeast Asia: Toward a Maritime Specialization?

Abstract

Homo sapiens’ cognitive skills played a significant role in their ability to adapt to various environments as they migrated out of Africa during the late Middle Pleistocene. Among these environments, marine ecosystems are believed to have been crucial for sustenance. Around 50,000 years ago, as H. sapiens dispersed from Asia to Australia, they embarked on what is considered the first significant phase of maritime adaptation in human history, requiring them to undertake open-water journeys through the islands of Southeast Asia. However, despite our knowledge of their nautical skills, direct evidence of open-sea navigation has yet to be conclusively discovered. In this context, we review the findings obtained from the study of ichthyoarchaeological remains at multiple sites dating from the late Pleistocene to the mid-Holocene in the Philippines, the Lesser Sunda Islands, and Okinawa. Across all the sites, fishing activities were primarily limited to the shoreline or near-coast areas, with the development of techniques tailored to the specific surrounding environments. This suggests that the management of marine resources was efficient, rendering offshore fishing potentially unnecessary and risky. However, such specialization would have required the development of sophisticated technologies and a robust intergenerational cultural transmission.

1. Introduction

Homo sapiens has demonstrated a remarkable ability to adapt to a wide array of environments ever since their migration out of Africa during the late Middle Pleistocene and late Pleistocene periods [1, 2]. Marine environments, in particular, have garnered significant attention due to their dense concentrations of fauna, rich in both protein and fatty acids, suggesting their importance for subsistence among H. sapiens. This has led to the hypothesis that these environments may have served as coastal highways for migration and settlement [3, 4]. The earliest archeological evidence of H. sapiens adapting to coastal habitats can be traced back to South Africa, where mollusk exploitation dates as far back as marine isotope stage (MIS) 6, around 191–123,000 BP (Before Present) [5]. However, intriguingly, the evidence for early symbolic use of marine shells by H. sapiens seems to disappear from the global archeological record after approximately 70,000 BP [6]. By at least 50,000 BP, the dispersal of H. sapiens from Asia to Australia through Island Southeast Asia (ISEA) marked a significant milestone in human maritime adaptation, which would have required open-water crossings via the Wallacean archipelago (Figure 1) [8].

Figure 1.

Map of Island Southeast Asia, the Philippines, and Wallacea, as well as the extent of the continental shelves at −130 m, the limits of the Coral Triangle, and Homo sapiens’ sites mentioned in the text (modified from Boulanger et al. [7]).

The Indo-Pacific area has a rich history of hominin evolution within tropical island environments long before the arrival of H. sapiens. ISEA, located in a region marked by significant tectonic activity involving the Pacific, Indo-Australian, and Eurasian continental plates, is also influenced by minor oceanic plates, such as the Philippine Plate and the Carolina Plate [9]. This area is part of the Pacific Ring of Fire, resulting in distinct biogeographic zones due to the historical isolation of species during periods of reduced sea levels [10]. The region is divided into three primary biogeographic zones: the Western Sunda, Eastern Sahul, and the intermediate Wallacean region (Figure 1). The latter represents a blend of species from both Sunda and Sahul, with ongoing scholarly debate about its classification. Therefore, the validity of the term “Wallacea” remains a topic of discussion, with some experts questioning its distinctiveness from the Sunda region [11, 12], and as to whether the Philippine archipelago should be included within the purview of Wallacea or categorized differently [13, 14, 15].

Building upon this rich geological context, various archaic human species have left their traces in the region, including H. erectus on Java, Indonesia, approximately 1.3 million BP [16], H. floresiensis on the Wallacean island of Flores around 100,000 BP [17], an unknown species on the Philippines dating back to 709,000 years ago [18], and the recent discovery of H. luzonensis on the island of Luzon approximately 67,000–50,000 BP [19, 20, 21]. However, these pre-H. sapiens hominins do not appear to have shown indications of a marine adaptation in Southeast Asia. Instead, it has been suggested that they might have colonized islands in the Lesser Sundas and Sulawesi accidentally [22]. It was only with the arrival of H. sapiens in the region that clear evidence of marine mollusk gathering [23, 24, 25, 26], marine navigation, and advanced fishing practices became apparent, dating back to at least 42,000 years ago at Asitau Kuru, previously known as Jerimalai, in East Timor [27, 28]. Despite significant natural climate-induced environmental changes occurring during the human colonization of ISEA, fishing activities persisted with indications of increased emphasis on marine resource acquisition during the transition from the terminal Pleistocene to the Holocene [29, 30]. Around 4000 BP, Austronesian-speaking communities emerged, bringing with them a range of practices such as pottery-making, horticulture, animal domestication, and long-distance obsidian trade. These communities rapidly expanded from Taiwan through the Philippines and possibly the Ryukyu archipelago in Japan to the distant Pacific Islands, reaching as far as Fiji and Tonga [31, 32]. During this period of Austronesian-speaking population expansion, marine adaptations received much attention, revealing evidence of highly advanced fishing capabilities, supporting the notion of Neolithic Austronesian maritime adaptation throughout the region [33, 34].

This chapter review focuses on assessing the degree of adaptation to marine and coastal environments during prehistory in ISEA. Here, we choose to use the terms “Phillipines” and “Wallacea” (Figure 1) to refer to two different areas. By comparing the presence or absence of fish remains and fishing strategies at various Paleolithic archeological sites, this study provides a broader chronological and cultural framework for understanding Homo sapiens’ coastal adaptation in this region, from its initial settlement by our species to the Austronesian diaspora.

2. Ichthyoarchaeology and Island Southeast Asia

Ichthyoarchaeology is the specialized branch of zooarchaeology that plays a crucial role in piecing together the subsistence strategies and cultural practices of ancient societies by examining archeological fish remains [35]. In the late 1970s, Leach [36, 37] introduced a method for analyzing fishbone assemblages from New Zealand and Pacific island sites. This method centered on identifying the “five paired cranial bones” (such as the dentary, articular, quadrate, premaxilla, and maxilla) and specific “special bones” characteristic of certain fish families. It was subsequently applied to numerous sites in the Pacific, contributing significantly to our understanding of these ancient cultures (e.g., Campos [38]). However, recently, a more comprehensive approach has emerged, surpassing this method, involving the identification of all fish remains, including postcranial elements, such as vertebrae. This comprehensive method allows for identification at the highest possible biological level and, when combined with improved reference collections, offers a more precise understanding of ecological data [39, 40, 41, 42, 43, 44, 45, 46, 47]. Nonetheless, it is important to note that, despite these advanced methods and extensive reference collections, the specific conditions of the study area often limit the ability to identify fish remains beyond the family level.

ISEA is located within the “Coral Triangle” (Figure 1) that stands out as a globally recognized hotspot of marine biodiversity [48], representing 76% of the world’s total species complement [49]. This region, which encompasses the coastlines of islands in Wallacea (eastern Indonesia and East Timor) and the Philippines archipelago, is home to an extraordinary array of more than 3500 marine species [50]. While this astonishing biodiversity presents certain challenges, it also highlights the variety and differences within fish families, such as scombrids (tunas, bonitos, and mackerels), which encompass numerous species with varying habitats and life histories, including some that could be found near the shore [51]. This remarkable richness in biodiversity can be attributed to several key factors, including (1) geological characteristics, (2) the physical environment, and (3) ecological processes [49]. The region’s extended and intricate geological history, marked by tectonic movements [52] and fluctuations in sea levels (Figure 1) [53], combined with the presence of some of the most recent coral fossil records [54], has led to evolutionary adaptations and the development of complex habitats such as the formation and disappearance of vital mangrove habitats along the coastline [49], which have played a significant role in shaping the history and subsistence strategies of H. sapiens in the region [29].

Paleontological evidence, such as the absence of large mammals and the presence of endemic dwarf species on the islands of Ryukyu, situated between Taiwan and the island of Kyushu in Japan, demonstrate that this archipelago has long been isolated from the mainland [55]. Similarly, the Philippines were never physically connected to the Sunda Shelf and channels between them progressively narrowed over time. On the island of Palawan, Philippines, this geological evolution potentially served as a pathway for the migration of fauna into Wallacea [56]. Interestingly, despite fluctuations in sea levels linked to climatic changes during the late Pleistocene, which at times dropped to depths of approximately 130 m below current levels, Wallacea remained isolated from any continental landmass due to the absence of land bridges (Figure 1) [53, 57]. As a result, the terrestrial ecosystems on most Wallacean islands are relatively depauperate in terms of biodiversity when compared to the continental landmasses of Sunda and Sahul [23]. This scarcity of terrestrial resources highlights the potential importance of marine environments for past human habitation in insular context, a significance that endures to this day [58]. Notably, several remarkable archeological sites spanning the Pleistocene-Holocene periods have yielded significant quantities of fish remains and remnants of fishing equipment, while, interestingly, some others have not (Figure 1).

3. Coastal adaptation, marine resources exploitation, and fishing in Island Southeast Asia

3.1 The Ryukyu Arc

The Ryukyu Islands have been a significant focal point for Japanese Pleistocene archeological research, largely due to the abundant presence of limestone in this region [59]. Evidence of human occupation in this archipelago dates back as far as 37,000 BP, as documented at Yamishita-cho Cave I on Okinawa Island in Central Ryukyu (Figure 1) [60]. This site has yielded a diverse array of remains, including marine shells, endemic deer bones, human remains, and fish bones (Table 1) [59]. Unfortunately, the archeological records of this site have been lost today, leaving us uninformed about the nature of the fish remains and coastal adaptation at that location.

Site and location	^14C chronology	NISP	Identified fish taxa	Exploited aquatic environment	Fishing gears
Yamashito-cho Cave I, Okinawa	From 37,000 BP	Unknown	Unknown	Coral reef?	None
Sakitaro Cave, Okinawa	36,500–13,000 cal. BP	9	Anguilla marmorata	Nearby river	Shell fish hooks
Shiraho-Saonetabaru, Ishigaki	From 21,000 cal. BP to medieval times	1072	Acanthuridae, Balistidae, Carcharhinidae, Clupeidae, Diodontidae, Labridae, Muraenidae Scaridae, Serranidae, Carcharhinidae	Coral reef/inshore fishing	None
Bubog I, Ilin	33,277–31,783 cal. BP to 4240–4081 cal. BP	1445	Acanthuridae, Balistidae, Belonidae, Carangidae, Carcharhinidae, Cirrhitidae, Clupeidae, Diodontidae, Haemulidae, Labridae, Lethrinidae, Mugilidae, Muraenidae, Scaridae, Scombridae, Serranidae, Sparidae, Tetraodontidae	Coral reef/outer part of the reef/mangrove?/inshore fishing	Net sinkers and bipoint fishing gorge
Bubog II, Ilin	9530–9320 cal. BP to Pre-Spanish era	1382	Acanthuridae, Balistidae, Belonidae, Carangidae, Carcharhinidae, Clupeidae, Diodontidae, Holocentridae, Labridae, Lethrinidae, Lutjanidae, Mugilidae, Muraenidae, Pomacanthidae, Scaridae, Serranidae, Siganidae	Coral reef/inshore fishing	None
Bilat, Mindoro	21,810–21,289 cal. BP to 285–1 cal. BP	678	Acanthuridae, Balistidae, Belonidae, Carcharhinidae, Diodontidae, Labridae, Lethrinidae, Lutjanidae, Mullidae, Muraenidae, Pomacanthidae, Scaridae, Serranidae, Siganidae	Coral reef/inshore fishing	None
Here Sorot Entapa, Kisar	15,500–1800 BP	105,780	Acanthuridae, Balistidae, Balistoidei, Belonidae, Carangidae, Carcharhinidae, Cirrhitidae, Diodontidae, Gerreidae, Haemulidae, Holocentridae, Kyphosidae, Labridae, Lethrinidae, Lutjanidae, Mullidae, Muraenidae, Nemipteridae, Ostraciidae, Pempheridae, Priacanthidae, Scaridae, Sciaenidae, Serranidae, Sparidae, Sphyraenidae, Tetraodontidae	Rocky reefs with steep profiles surrounding the island/inshore fishing	Shell fish hooks
Tron Bon Lei, Alor	21,584–21,029 cal. BP to 3561–3455 cal. BP	39,349	Acanthuridae, Balistidae, Belonidae, Carangidae, Diodontidae, Elasmobranchii, Holocentridae, Labridae, Lethrinidae, Lutjanidae, Ostraciidae, Scaridae, Scombridae, Serranidae	Coral reef/outer part of the reef/ inshore fishing	Shell fish hooks
Makpan, Alor	40,360–38,585 cal. BP to recent time	Unknown	Acanthuridae, Balistidae, Diodontidae, Elasmobranchii (sharks/rays), Holocentridae, Kyphosidae, Labridae, Lethrinidae, Scaridae, Scombridae, Serranidae	Coral reef/outer part of the reef/ inshore fishing	Shell fish hooks
Asitau Kuru (Jerimalai), East Timor	46,529–43,085 cal. BP to Neolithic	55,287	Acanthuridae, Balistidae, Belonidae, Carangidae, Carcharhindae, Diodontidae, Holocentridae, Labridae, Lethrinidae, Lutjanidae, Muraenidae, Ostraciidae, Pomacanthidae, Scaridae, Sciaenidae, Scombridae, Serranidae, Sphyraenidae, Tetraodontidae	Deep channel between Valu Sere and Jaco Islands/inshore fishing	Shell fish hooks, bone points used as part of complex hooks for trolling?
Matja Kuru 2, East Timor	36,866–35,282 cal. BP to 1000 BP	487	cf. Acanthuridae, Balistidae, Cichlidae, Eleotridae, Gerreidae, cf. Pomacentridae, Scaridae, Scombridae, Serranidae	Coral reef/inshore/freshwater (estuarine and river) fishing	Shell fish hooks, bone points used as part of complex hooks for trolling?
Laili, East Timor	43,704–41,429 cal. BP to 8555–8316 cal. BP	491	Acanthuridae, Anguillidae, Balistidae, Belonidae, Carangidae, Eleotridae, Mugilidae, cf. Scaridae, Sciaenidae, Serranidae, Siluriformes	Coral reef/inshore/freshwater (estuarine and river) fishing	None

Table 1.

Synthesis of ISEA Paleolithic sites for which fish remains assemblage have been studied, as well as associated chronology, number of identified remains (NISP), identified fish taxa, exploited aquatic environments, and fishing gears.

On the same island of Okinawa, remains dating from 23,000 to 20,000 BP, including the discovery of the oldest known shell fishhook, were found at Sakitori Cave (Figure 1). While the site has provided insights into terrestrial fauna, such as wild boar and extinct endemic deer, it has yielded only nine fish remains, some of which belong to a species of freshwater eel, associated with freshwater crustacean remains (Table 1) [61]. Similar fauna, but no fish remains, were discovered at the Minatogawa fissure, located at the mouth of the Yugi-gawa River, where four adult human remains, showing affinities with Australo-Melanesian populations, dating back to 22,000–20,000 BP, were found [62, 63]. Moreover, human remains dated to 15,200 BP were recovered at Shimojibaru Cave on Kume Island, around 100 km from Okinawa Island [64].

In the southern part of the Ryukyu archipelago, in the Yaeyama Islands, the oldest known occupation dates to 26,800–25,800 (uncalibrated) BP, specifically at the Pinza-abu site on Miyako Island. This early habitation was associated with terrestrial fauna, including deer, wild boar, and microvertebrates, but no fish remains were recovered [65]. Only the site of Shiraho-Saonetabaru on Ishigaki Island (Figure 1) uncovered a small assemblage of marine coral reef fish remains (Table 1), alongside human remains, dated between 24,000 and 19,000 BP [66, 67].

3.2 The Philippines

In the Philippines, the earliest known H. sapiens fossil was discovered in Tabon Cave, Southern Palawan (Figure 1), dating back to approximately 39–33,000 BP [68, 69, 70]. In the northern part of the same island, human fossils and a variety of faunal remains were recovered at the archeological site of Ille Cave dating from around 11,000 BP to the mid-Holocene period (Figure 1) [71]. However, no fish remains were found at those sites.

Moving eastward to the southwestern part of Mindoro Island, located the archeological site of Bubog I, along with its neighboring sites, Bubog II and Bilat Cave, all of which provide evidence of early human habitation (Figure 1). Specifically, Bubog I, located on the small island of Ilin, is a stratified shell-midden site with a chronological range spanning approximately 33,000 to 4000 BP [29, 72, 73]. As a result, the sequence at Bubog I provides valuable insights into significant paleoenvironmental and paleogeographic changes that occurred at the end of the Pleistocene and during the mid-Holocene. Notably, Pawlik and colleagues [72] have emphasized a significant shift in molluscan resources along the stratigraphic profile, transitioning from a predominantly mangrove-based resource to one primarily derived from marine environments. This shift is further evidenced by the presence of mangrove crab species, such as Scylla sp. and Cardisoma carnifex, in the lower layers of the stratigraphy, reflecting adaptations in subsistence strategies to changing landscapes [29, 74]. The fauna at the site, which includes mollusks, crustaceans, micromammals, coastal, and coral reef fishes (Table 1), is associated with a specific lithic industry primarily composed of hammer-stone remains [72]. Evidence of the consumption of toxic fish belonging to the Diodontidae family (porcupine fish) has also been demonstrated at that site [75]. Additionally, a Tridacna shell adze, securely dated to 7550–7250 cal. BP, and perhaps implied in the manufacture of dugout canoes, was recovered [76], along with a fishing gorge found in deposits below the shell midden. Radiocarbon dating places the gorge’s age between 35,000 and 33,000 BP [29, 73]. Furthermore, two igneous pebbles with waisted modifications, possibly used as net sinkers, were also discovered within the shell midden [29, 73].

3.3 Wallacea

In the northern Wallacean region, various archeological sites, such as Leang Sarru in the Talaud Islands during the early Holocene, Golo Cave on Gebe Island from the late Pleistocene, and the Goa Topogaro sites in Central Sulawesi, seem to have primarily relied on shellfish gathering rather than showing any signs of specialized fishing practices (Figure 1) [26, 77, 78, 79].

Moving to the Lesser Sunda Islands near the coast of East Timor, the Here Sorot Entapa rockshelter on Kisar Island, Indonesia (Figure 1), has yielded a collection distributed in a stratigraphic sequence of nine units. Two distinct chronological phases have been identified: an initial occupation dating back to approximately 15,500 years ago, continuing into the early Holocene around 9500 years ago, and a subsequent neolithic phase extending from 4900 to 1800 BP [80]. This site boasts an abundance of coastal and coral reef fish remains (Table 1), marine mollusks, and microvertebrates, including reptiles, birds, and mammals. Among these remains are two extinct rat species, which may indicate changes in forested environments during the late Holocene [80]. Additionally, the site has yielded a range of artifacts, including items made from shells, shell fish hooks, and coral artifacts [80].

The nearby Tron Bon Lei site, located on the southwest coast of Alor Island (Figure 1), has also revealed a similar archeological assemblage, which has been dated to a span between 21,000 and 3500 BP. This assemblage is predominantly composed of coastal and coral reef fish remains with a small proportion of scombrids (tunas, bonitos, mackerels) (Table 1). Samper Carro and co-authors [30] propose a shift in the types of fish present, transitioning from carnivorous and open-water species during the terminal Pleistocene to smaller herbivorous and omnivorous species after the early Holocene. Several factors could account for this change in the relative abundance of different species, including variations in fishing techniques, evolving culinary preferences, shifts in prey availability due to environmental changes, or alterations in social organization over time. Furthermore, shell fish hooks associated with mortuary practices have been discovered at this site, dating back to approximately 12,000 BP [81], adding an interesting dimension to our understanding of the site’s cultural significance.

More recently, in a study conducted by Kealy and co-authors [82], a similar fish assemblage, both in terms of the size and variety of fish species present (Table 1), has been discovered at the site of Makpan, dated from around 40,000 BP, and situated on the western side of Alor Island, just a few kilometers away from the Tron Bon Lei site (Figure 1), highlighting the significance of marine inshore resources for those prehistoric communities.

At the site of Asitau Kuru (Jerimalai) in East Timor (Figure 1), dated from 44,000 BP, fishing activities appear to have extended to trolling scombrids (mackerels, tunas, bonitos) from boats, demonstrating a high level of planning, sophisticated maritime technology, and sailing skills [7, 28] (Table 1). A few kilometers inland from the island of Timor, the analysis of materials excavated at the inland sites of Matja Kuru 2 and Laili has provided valuable insights (Figure 1). Of particular note, the Laili site has yielded the oldest date for human occupation in Wallacea, dating back to 44,600 BP. Additionally, evidence of coastal exploitation has emerged through the discovery of a few marine fish remains, as well as evidence of inland fishing (Table 1) [27]. This evidence suggests a network of interaction between inland and coastal sites in East Timor during the Pleistocene [23, 27].

4. Discussion

This review explores the marine adaptations of H. sapiens across ISEA, spanning from the Ryukyu Arc to the Wallacea region. It enables broad comparisons along a north-south gradient among archeological sites. These sites encompass relatively extensive stratigraphic profiles, covering the transition from the terminal Pleistocene to the Holocene period. The timeline ranges from 44,600 BP for the oldest findings in East Timor [23] to the Neolithic era. These archeological assemblages come in various sizes, from sites such as Here Sorot Entapa, housing hundreds of thousands of remains, to Sakitari Cave and Matja Kuru 2, with fewer than one hundred remains (Table 1) [27, 61, 80]. Importantly, these sites yield not only ichthyoarchaeological material but also cultural materials, such as fishing equipment (Table 1), shell adzes, and symbolic artifacts. When combined with zooarchaeological data, these findings provide valuable insights into the adaptive maritime subsistence strategies developed by these ancient Paleolithic populations.

When considering the Okinawa sites, such as Shiraho Saonetabaru and the Philippines sites, specifically Bubog I, Bubog II, and Bilat Cave, it is apparent that they exhibit a relatively lower level of occupation intensity over time when compared to coastal sites in the Wallacea region [66, 83]. Here Sorot Entapa, Tron Bon Lei, Makpan, and Asitau Kuru, conversely, have yielded substantial archeological assemblages, with occupation status showing fluctuations throughout their stratigraphic profiles [7, 28, 30, 80, 82]. These sites consistently emphasized specific foraged habitats over the long term. Specifically, Here Sorot Entapa focused on the extensive coral reef terraces around Kisar Island, while Asitau Kuru concentrated its activities on the easily accessible deep channel situated between the site and Jaco Island [7, 80]. Unlike the southern Wallacean islands, the northern locations likely offered a wider range of subsistence opportunities due to the availability of diverse terrestrial resources. The Pleistocene inhabitants of archeological sites in northern Wallacea seem to have relied on a combination of terrestrial resources and shellfish gathering. These discoveries emphasize the significance of terrestrial game hunting, plant foraging, and rainforest exploitation in their daily lives, creating a distinct contrast with the southern Wallacean record [79]. Moreover, the fishing area of the Okinawa and Philippines sites appears less clearly defined, even though they are situated along the coast and involve reef fishing, with potential utilization of mangrove environments at Bubog I during the Last Glacial Maximum [29]. Additionally, the inland sites of Matja Kuru 2 and Laili despite having low number of identified remains (NISP) are particularly noteworthy as they provide evidence of human exploitation in both marine and freshwater environments (Table 1). This suggests a diverse subsistence strategy that encompassed a broader range of resource utilization within these regions [27].

Within this framework, it becomes evident that human activities in the ISEA region predominantly focused on the exploitation of near-shore environments. Differences observed among archeological sites can be directly attributed to local environmental variations and, in certain instances, influenced by factors such as fluctuations in climate, changes in sea levels, and taphonomic biases, affecting the preservation of remains. The exploitation of specific local environments necessitated the development of adaptive fishing technologies and techniques. When we compare this evidence with archeological and ethnographic data from the Pacific, which demonstrate opportunistic resource exploitation, we can make inferences about the fishing techniques practiced in ISEA. It appears that a wide range of fishing techniques were likely employed at these sites. This hypothesis is supported by the discovery of fishing-related artifacts such as fishhooks, fishing gorges, and net sinkers (Table 1) [28, 61, 73, 75, 80, 81, 82, 84]. Of particular interest is the cultural convergence observed between the Okinawan rotative shell fish hooks and those found at the Wallacean sites [61].

Hence, a hypothesis of maritime specialization emerges among these human groups, particularly in the southern Wallacea region, where it appears that humans primarily relied on fishing, especially during the initial stages of island settlement [85]. This specialized focus on maritime resources likely played a pivotal role in shaping the subsistence strategies and cultures of these early island communities and sustaining their populations. However, despite their evident knowledge of nautical skills, there is no indication that they engaged in offshore fishing, which could have posed unnecessary risks [7]. Additionally, Boulanger and co-authors [75] highlighted the presence of Diodontidae (porcupinefish), in the archeological sites of Bubog I, II, and Bilat in Mindoro, Philippines, dating back to around 13,000 BP. These findings suggest that early island inhabitants were actively using poisonous fish. Porcupinefish are known to carry toxins throughout their bodies, with certain organs containing higher concentrations of toxicity than others. It, therefore, implies that the people inhabiting these sites possessed advanced cultural knowledge. They were able to prepare porcupinefish in a way that made them safe for consumption, indicating a unique instance of human processing of poisonous substances for food. Those findings further highlight the social aspects of fishing among those Paleolithic islanders.

5. Conclusion

The archeological evidence of coastal adaptation found in Paleolithic sites across ISEA is a testament to the maritime expertise of ancient inhabitants in this region. It highlights their ability to thrive in coastal environments and sustain themselves by effectively utilizing coastal resources. What makes this evidence particularly intriguing is the coexistence of intricate and sophisticated patterns related to coastal adaptation. These patterns encompass a wide range of behaviors, such as specialized fishing techniques, probable boat-building skills, the preparation and consumption of toxic fish, and the development of tools tailored for marine activities. Notably, some of these tools have been discovered in burial contexts, suggesting their cultural and symbolic significance in the lives of these early island inhabitants [81]. This coexistence suggests a highly complex and organized approach to life by these ancient communities. Furthermore, the archeological findings hint at the evolution of high-level cognitive processes among these ancient populations. The ability to adapt to a coastal lifestyle would have required not only physical skills but also advanced cognitive capabilities. This includes the capacity to plan and execute complex tasks such as navigation, resource management, and the development of strategies for successful coastal living. In essence, coastal adaptation’s patterns in ISEA’s Paleolithic archeological record represent a major step forward in human evolution. It signifies the concurrent development of both cognitive and subsistence skills, showcasing how our ancestors not only survived but thrived in challenging coastal environments. These discoveries provide valuable insights into the remarkable adaptability and ingenuity of early human populations and their capacity to exploit diverse ecological niches [2].

Acknowledgments

This study has been funded by the Japanese Society for the Promotion of Science and by a research grant of the NIHU Global Area Studies Program, Maritime Asian and Pacific Studies (MAPS).

Conflict of interest

The author declares no conflict of interest.