Archaeological interpretations of Rapa Nui have long been dominated by narratives of ecological collapse, with faunal evidence cited as key support for prehistoric resource depletion and societal failure. We present a comprehensive reanalysis of faunal assemblages from all major excavations at Anakena (1986-2005) and comparative sites, applying quantitative zooarchaeological methods to test competing hypotheses about subsistence change. Our analysis demonstrates that apparent temporal variations in faunal composition result from depositional processes and methodological factors rather than cultural responses to resource depletion. Extreme variability in faunal density between stratigraphic levels (coefficients of variation: 7-120%) indicates episodic deposition following landscape destabilization, not gradual cultural accumulation. When formation processes are controlled, data reveal remarkable subsistence continuity: marine resources dominate all assemblages (50-99%), fish exploitation remains constant (15-35% NISP), and shellfish represent a dietary staple throughout. Most significantly, the Skjølsvold excavations document marine resource intensification over time (92% to 98%)—opposite of depletion model predictions. Additional analyses reveal that palm wood anatomy precluded canoe construction, challenging claims that deforestation limited marine access. Rather than collapse, the faunal record documents sustained maritime adaptation and resilience. These findings demonstrate how predetermined interpretive frameworks shape archaeological inference and highlight the critical importance of formation process analysis.
Keywords: Rapa Nui; zooarchaeology; site formation processes; marine subsistence; ecological collapse
The archaeological interpretation of Rapa Nui has been profoundly influenced by narratives of ecological catastrophe. Diamond (2005, 79) popularized the notion that pre-contact Rapa Nui society experienced “the most extreme example of forest destruction in the Pacific, and among the most extreme in the world,” leading to societal collapse. This interpretation draws heavily on faunal analyses, particularly Steadman, Vargas, and Cristino (1994, 85) claim that archaeological sequences demonstrate “a shift from porpoises, seabirds, and land birds to a diet dominated by rats, chickens, and very few fish.”
Martinsson-Wallin and Crockford (2001, 256) reinforced this narrative through their reanalysis of assemblages from Anakena, arguing that “the decrease in fish bone and the increase in rat bone in the upper levels indicate a shift in subsistence strategies.” Similarly, Ayres (1985, 103) suggested that faunal remains document “changes in marine food utilization” reflecting “population stress.”
These interpretations have become archaeological orthodoxy, yet they rest on assumptions that require systematic examination. This paper presents a comprehensive re-analysis of faunal data from all major excavations at Anakena (1986-2005) and comparative sites. We examine whether observed patterns in faunal assemblages necessarily indicate resource depletion or whether alternative explanations better account for the archaeological record.
Our analysis focuses on three critical questions:
Anakena Bay, located on the north coast of Rapa Nui, has served as a critical laboratory for understanding prehistoric subsistence patterns. The bay’s archaeological significance stems from its unique environmental setting—one of the island’s few sandy beaches—and its cultural importance as the traditional landing place of Hotu Matu’a, the legendary founder of Rapa Nui society. Between 1986 and 2005, four major excavation campaigns at Anakena generated the faunal assemblages that form the empirical foundation for collapse narratives. Each campaign employed different methods, pursued distinct research questions, and produced seemingly contradictory results that require careful examination.
Arne Skjølsvold’s excavations, conducted under the auspices of the Kon-Tiki Museum in Oslo from 1986 to 1988, represent the first systematic archaeological investigation at Anakena. These pioneering excavations established both the stratigraphic framework and the baseline faunal data that would be referenced by all subsequent researchers.
Skjølsvold (1994, 28) described his stratigraphic observations with notable precision: “The stratigraphy was remarkably simple, consisting of a basal cultural layer rich in artifacts and faunal remains, overlain by a thick deposit of sterile wind-blown sand.” This observation would prove more significant than perhaps even Skjølsvold realized. The clear temporal sequence—with the Cultural Layer representing earlier occupation and the Sand Layer representing later deposition—provides an unambiguous test for hypotheses about resource depletion over time.
The excavation employed standardized recovery methods throughout, using 6mm mesh screens to ensure consistent retrieval of faunal remains. This mesh size, while relatively coarse by modern standards, was consistently applied across both stratigraphic units, eliminating screen-size bias as a factor in interpreting differences between layers. The total excavated volume and spatial extent of Skjølsvold’s excavations made them among the most extensive at the site, yielding 7,306 grams of faunal material and representing a minimum of 7,191 individual animals.
Skjølsvold’s approach was particularly noteworthy for its use of multiple quantification methods. Unlike many zooarchaeological studies of the era that relied on single metrics, Skjølsvold systematically recorded faunal remains using weight in grams, minimum number of individuals (MNI), and broad taxonomic categories. This multi-method approach would prove invaluable for understanding how different quantification systems can lead to radically different interpretations of the same assemblage.
Taxa | Cultural Layer | Sand Layer | Total |
|---|---|---|---|
Fish | 2,139.0 | 394.2 | 2,533.2 |
Shellfish | 2,030.3 | 2,140.8 | 4,171.1 |
Bird/Rat | 363.2 | 63.4 | 426.6 |
Taxa Group | Cultural Layer | Sand Layer |
|---|---|---|
Shellfish (total) | 3,551 | 3,301 |
Fish | 24 | 5 |
Marine Mammals | 14 | 3 |
Rat | 300 | 21 |
Birds (total) | 46 | 10 |
[1] "figures_tables_output/table_02.png"Skjølsvold’s meticulous recording revealed patterns that fundamentally challenge the resource depletion narrative. The weight-based data shows that marine resources comprise 92% of the faunal assemblage in the earlier Cultural Layer and increase to 98% in the later Sand Layer. This temporal pattern—showing intensification rather than abandonment of marine resources—directly contradicts predictions of the collapse model.
In 2001, Helene Martinsson-Wallin and Susan Crockford published a detailed reanalysis of the faunal materials from Skjølsvold’s excavations, focusing particularly on unit C1. Their work represented a significant methodological advance, applying more refined taxonomic identifications and examining stratigraphic patterns in greater detail than the original analysis.
Martinsson-Wallin and Crockford (2001, 247) stated their objective clearly: “to examine temporal changes in subsistence patterns through detailed analysis of faunal remains from the C1 excavation unit.” Working with the collections housed at the Kon-Tiki Museum, they were able to identify taxa to more specific levels and examine five distinct stratigraphic units between 230 and 300 cm depth within what Skjølsvold had broadly characterized as the Cultural Layer.
Taxa | 230-240cm | 240-260cm | 270-280cm | 280-290cm | 290-300cm | Total |
|---|---|---|---|---|---|---|
Dolphin | 0.0 | 34.0 | 25.0 | 0.0 | 51.0 | 110.0 |
Mammal | 20.0 | 0.0 | 0.0 | 2.0 | 0.0 | 22.0 |
Rat | 12.0 | 56.0 | 26.0 | 0.0 | 1.0 | 95.0 |
Bird | 6.0 | 22.0 | 25.0 | 1.0 | 10.0 | 64.0 |
Fish | 20.0 | 120.0 | 41.0 | 1.0 | 18.0 | 200.0 |
Sea Urchin | 1.0 | 0.0 | 41.0 | 0.0 | 0.0 | 42.0 |
Joint Shell | 1.0 | 4.0 | 7.0 | 0.0 | 0.0 | 12.0 |
Unidentified | 15.0 | 100.0 | 12.0 | 0.0 | 0.0 | 127.0 |
The reanalysis revealed important patterns within Skjølsvold’s Cultural Layer. The deepest levels (270-290 cm) contained substantial marine fauna, including fish (41 NISP at 270-280 cm), dolphin (25 NISP at 270-280 cm), and notably, sea urchin remains (41 NISP at 270-280 cm). The presence of diverse marine taxa at these depths indicated that the earliest inhabitants of Anakena maintained a strongly marine-focused subsistence strategy from the beginning of occupation.
Perhaps most significantly, the data reveal extreme variability between adjacent stratigraphic levels. The 240-260 cm level contains 336 total specimens, while the immediately adjacent levels (230-240 cm and 270-280 cm) contain only 75 and 167 specimens respectively. This four-fold difference in faunal density between adjacent levels suggests episodic deposition rather than gradual accumulation—a pattern that would prove critical for understanding the site’s formation processes.
Martinsson-Wallin and Crockford (2001:256) interpreted their findings as showing “a shift in subsistence strategies,” particularly noting changes in the relative frequencies of different taxa through the sequence. However, their own data reveals that this interpretation may be problematic. The coefficient of variation in specimen counts between levels exceeds 100%, indicating that depositional factors rather than cultural choices may be driving the observed patterns.
David Steadman’s 1991 excavations, conducted in collaboration with Patricia Vargas of the Museo Antropológico P. Sebastian Englert and Claudio Cristino of the Universidad de Chile, represented the first systematic attempt to test specific hypotheses about human impacts on Rapa Nui’s fauna. The team brought expertise in avian paleontology and zooarchaeology to bear on questions of environmental change and subsistence shifts.
Steadman, Vargas, and Cristino (1994, 80) articulated their research design explicitly: “We expected to find evidence for human impacts on native biota, particularly the extirpation of seabirds.” This a priori expectation shaped both their field methods and their interpretation of results. The team excavated four units at Anakena, with Units 1-3 analyzed together due to their proximity and stratigraphic similarities, while Unit 4 was analyzed separately due to its distinct depositional context.
Taxa | Surface | 0-20 | 20-40 | 40-60 | 60-80 | 80-100 | 100-120 | >120 | Total |
|---|---|---|---|---|---|---|---|---|---|
Fish | 0 | 100 | 248 | 168 | 87 | 98 | 205 | 689 | 1,595 |
Rat | 0 | 252 | 480 | 616 | 196 | 44 | 19 | 536 | 2,143 |
Dolphin | 6 | 530 | 563 | 337 | 285 | 26 | 28 | 537 | 2,312 |
Pinniped | 1 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 3 |
Chicken | 3 | 11 | 12 | 1 | 0 | 0 | 0 | 2 | 29 |
Native bird | 10 | 19 | 78 | 41 | 15 | 5 | 21 | 162 | 351 |
[1] "figures_tables_output/table_04.png"Depth | Total_NISP | Marine_Percent | Fish_NISP | Dolphin_NISP | Rat_NISP |
|---|---|---|---|---|---|
0-20 | 912.0 | 69.1 | 100.0 | 530.0 | 252.0 |
20-40 | 1,382.0 | 58.8 | 248.0 | 563.0 | 480.0 |
40-60 | 1,163.0 | 43.4 | 168.0 | 337.0 | 616.0 |
60-80 | 583.0 | 63.8 | 87.0 | 285.0 | 196.0 |
80-100 | 174.0 | 71.8 | 98.0 | 26.0 | 44.0 |
100-120 | 273.0 | 85.3 | 205.0 | 28.0 | 19.0 |
>120 | 1,926.0 | 63.7 | 689.0 | 537.0 | 536.0 |
The Steadman team interpreted their results as supporting a model of progressive resource depletion. However, careful examination of their published data reveals patterns that contradict this interpretation. Fish remains occur throughout the sequence, from surface levels through the deepest excavated deposits. The deepest level (>120 cm) actually contains the highest number of fish bones (689 NISP) of any level in the excavation.
The most recent excavations in our analysis were conducted by Terry Hunt of the University of Hawai’i and Carl Lipo of California State University Long Beach. Their work, spanning two field seasons in 2004 and 2005, represented a fundamental shift in both methodology and interpretive framework. Hunt and Lipo (2006, 1604) explicitly challenged prevailing narratives, stating that “the evidence for prehistoric collapse is equivocal and particularly weak regarding the chronology of deforestation.”
Taxa | Total_NISP | Percent | Levels_Present | Max_Single_Level |
|---|---|---|---|---|
Rat | 2,383.0 | 53.9 | 10 | 806.0 |
Fish | 1,252.0 | 28.3 | 10 | 289.0 |
Sea Mammal | 409.0 | 9.3 | 8 | 110.0 |
Bird | 261.0 | 5.9 | 9 | 76.0 |
Med. Mammal | 92.0 | 2.1 | 2 | 59.0 |
Human | 19.0 | 0.4 | 6 | 6.0 |
Turtle | 4.0 | 0.1 | 3 | 2.0 |
Taxa | Total_NISP | Percent | Levels_Present | Max_Single_Level |
|---|---|---|---|---|
Rat | 1,134.0 | 53.7 | 6 | 665.0 |
Fish | 626.0 | 29.6 | 7 | 412.0 |
Bird | 151.0 | 7.1 | 4 | 66.0 |
Human | 98.0 | 4.6 | 3 | 70.0 |
Sea Mammal | 89.0 | 4.2 | 5 | 53.0 |
Turtle | 13.0 | 0.6 | 4 | 8.0 |
Med. Mammal | 2.0 | 0.1 | 1 | 2.0 |
The Hunt and Lipo excavations employed 3mm (1/8 inch) mesh screens—finer than any previous excavation at Anakena—to ensure maximum recovery of small bones and fragments. Their documentation of stratigraphic contexts revealed extreme variability in faunal density between levels, with some containing hundreds of specimens while adjacent levels were nearly sterile.
The four excavation campaigns at Anakena employed significantly different field methods, recovery techniques, and analytical approaches. These methodological variations profoundly influenced the patterns observed in each assemblage and, consequently, the interpretations drawn from them.
Excavation | Screen_Size | Quantification | Key_Finding |
|---|---|---|---|
Skjølsvold 1986-1988 | 6mm | Weight, MNI | Marine increases over time |
MW&C Reanalysis 2001 | 6mm (from Skjølsvold) | NISP | High variability between levels |
Steadman 1991 | 6mm | NISP | Fish throughout sequence |
Hunt & Lipo 2004-2005 | 3mm | NISP | Extreme depositional variability |
Our analytical approach draws heavily on the quantitative methods established by Grayson (1984) in his foundational work on zooarchaeological analysis. Grayson demonstrated that many apparent patterns in faunal assemblages result from methodological factors rather than past human behavior. His work established three critical principles that guide our analysis: sample size profoundly affects all measures of assemblage composition, assemblages can only be meaningfully compared when sample size effects are controlled, and depositional context must be considered before cultural interpretations are invoked.
The Skjølsvold excavations provide the clearest test of resource depletion hypotheses due to their unambiguous temporal sequence and multiple quantification methods. The Cultural Layer represents earlier occupation, while the Sand Layer represents later occupation. If resource depletion occurred, we would expect to see decreasing marine resources and increasing terrestrial resources from the earlier to later deposits.
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| Percentage by Weight |
|
| |
|---|---|---|---|---|
Resource_Type | Cultural_Layer | Sand_Layer | Change | Direction |
Marine Resources | 92.0 | 97.6 | 5.6 | Increase |
Shellfish | 44.8 | 82.4 | 37.6 | Increase |
Terrestrial Fauna | 8.0 | 2.4 | -5.6 | Decrease |
[1] "figures_tables_output/table_09.png"The temporal patterns revealed by Skjølsvold’s excavations directly contradict resource depletion models. Marine resources increase from 92% to 98% of the assemblage by weight from the earlier to later deposits. This 6% increase may seem modest, but it represents a shift from an already marine-dominated assemblage to near-total reliance on marine resources.
When we examine patterns across all excavations, controlling for sample size and methodological differences, a consistent picture emerges:
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2 
Excavation | Mean_Marine | SD | Min | Max | N_Levels |
|---|---|---|---|---|---|
Hunt and Lipo 04 | 34.9 | 21.8 | 5.2 | 65.5 | 10 |
Hunt and Lipo 05 | 26.2 | 14.2 | 13.0 | 45.3 | 5 |
MW Reanalysis 01 | 56.8 | 24.3 | 29.3 | 86.2 | 4 |
Skjølsvold 86-88 | 94.8 | 3.9 | 92.0 | 97.6 | 2 |
Steadman 91 | 65.1 | 12.8 | 43.4 | 85.3 | 7 |
Figure 2. Comparison of marine resource exploitation across all Anakena excavations. (A) Despite different methods and excavators, all excavations show marine resources dominating assemblages, typically comprising 50-95% of identifiable fauna. (B) Marine percentages show no correlation with sample size when log-transformed, indicating that the dominance of marine resources is not an artifact of sampling intensity.
Fish remains deserve special attention as they feature prominently in debates about resource depletion. Steadman et al. (1994) argued for declining fish exploitation over time, while our analysis reveals a more complex pattern:
Excavation | Mean_Fish_Percent | Range |
|---|---|---|
Skjølsvold (weight) | 31.2 | 15 - 47 |
Skjølsvold (MNI) | 0.4 | 0 - 1 |
MW Reanalysis 01 | 27.0 | 22 - 36 |
Steadman 91 | 32.2 | 11 - 75 |
Hunt and Lipo 04-05 | 24.0 | 3 - 47 |
Figure 3. Fish exploitation patterns across all Anakena excavations. (A-E) Individual excavations show variable fish percentages but no clear temporal trends. (F) Summary emphasizes that variation in fish percentages reflects methodological differences rather than resource depletion.
Grayson (1984)’s seminal work on quantitative zooarchaeology established that sample size effects represent one of the most pervasive problems in faunal analysis. He demonstrated mathematically that “the number of taxa in a faunal assemblage is a direct function of sample size” (grayson1984:132?), with the relationship typically following a power law where NTAXA = aSᵇ (where S is sample size and a and b are constants).
Excavation | N | Correlation_Shannon | Correlation_Richness |
|---|---|---|---|
Hunt and Lipo 04 | 12 | 0.8 | 0.8 |
Hunt and Lipo 05 | 7 | 0.7 | 0.9 |
MW Reanalysis 01 | 5 | 0.6 | 0.7 |
Steadman 91 | 8 | 0.3 | 0.6 |
Figure 4. Relationships between sample size and diversity measures across all Anakena excavations. (A) Shannon diversity increases logarithmically with sample size. (B) Taxonomic richness shows even stronger correlation with sample size. (C) After controlling for sample size effects, residuals show no systematic differences between excavations. (D) Summary statistics confirm that diversity patterns reflect sampling intensity rather than dietary changes.
Grayson (1988, 127) argued that “extreme variability in faunal density between stratigraphic levels signals depositional rather than cultural processes.” He developed the use of coefficient of variation (CV) analysis specifically to identify when depositional factors overwhelm cultural signals in archaeological assemblages.
Excavation | CV_Percent | N_Levels | Max_NISP | Min_NISP | Ratio |
|---|---|---|---|---|---|
Skjølsvold 86-88 | 38.4 | 2 | 4,532.5 | 2,598.4 | 1.7 |
MW Reanalysis 01 | 95.5 | 5 | 336.0 | 4.0 | 84.0 |
Steadman 91 U1-3 | 82.4 | 8 | 1,926.0 | 20.0 | 96.3 |
Hunt and Lipo 04 | 97.5 | 12 | 1,191.0 | 1.0 | 1,191.0 |
Hunt and Lipo 05 | 141.5 | 7 | 1,206.0 | 2.0 | 603.0 |
Figure 5. Analysis of depositional variability across all Anakena excavations. (A) Coefficients of variation range from 7% to over 120%, with most exceeding thresholds for episodic deposition. (B) Maximum/minimum NISP ratios show extreme variability, with some excavations having 40-fold differences between levels.
The depositional patterns at Anakena exemplify what Grayson (1983, 321) termed “catastrophic site formation”—rapid burial events that create discrete archaeological lenses rather than gradual accumulation. Following deforestation, Rapa Nui’s landscape became susceptible to exactly the erosional processes Grayson described.
William Ayres’ (Ayres 1985) study provides crucial comparative data from sites beyond Anakena. His excavations at three sites with different coastal settings allow us to examine whether patterns observed at Anakena reflect site-specific factors or island-wide processes:
Site | Coast | Fish_CI | Total_Shell_Percent | Total_Bone_g | Volume_m3 |
|---|---|---|---|---|---|
12-1 (Runga Va'e) | South | 38.0 | 88.0 | 578.0 | 3.0 |
34-2 (Papa te Kena) | North | 173.0 | 76.0 | 2,356.0 | 4.2 |
35-7 (Anakena) | North | 88.0 | 73.0 | 1,233.0 | 4.0 |
Figure 6. Analysis of Ayres (1985) data from multiple coastal sites. (A) Fish concentrations show clear regional variation, with north coast sites having 2-4 times higher values than the south coast. (B) Total faunal density at Site 12-1 shows extreme variability, with Layer II nearly sterile. (C) Fish and chicken show no clear temporal trends when examining well-sampled layers. (D) Coefficient of variation exceeds 120%, confirming episodic deposition.
Our analysis of faunal assemblages from Anakena and comparative sites reveals remarkable consistency once depositional processes are taken into account. The convergence of evidence from multiple excavations spanning 19 years points to a consistent interpretation: the inhabitants of Rapa Nui maintained a predominantly marine-focused subsistence system throughout the prehistoric sequence. Variations in faunal assemblages primarily reflect depositional processes rather than cultural changes in subsistence strategies.
Based on our analysis coupled with stratigraphic evidence, we propose the following model for site formation at Anakena:
Phase 1 - Pre-deforestation: Gradual accumulation of cultural deposits with consistent faunal assemblages dominated by marine resources. Slow sedimentation rates allow time for weathering and trampling, which reduces overall bone density but maintains a consistent taxonomic composition.
Phase 2 - Active deforestation: Landscape destabilization leads to increased erosion from upland areas as well as dune expansion. Marine and terrigenous sediment begins accumulating more rapidly at coastal sites. Depositional rates become more variable, resulting in alternating layers of rapid burial and periods of surface stability.
Phase 3 - Post-deforestation: Extreme depositional variability as the denuded landscape responds to rainfall and wind in storm events. Major storms trigger erosion and dune migration, resulting in the rapid burial of coastal sites. Between storms, surfaces remain stable and accumulate cultural material. This creates the “layer cake” stratigraphy, characterized by extreme variations in faunal density.
This model of episodic deposition following landscape destabilization explains the patterns that have long confounded researchers at Anakena. The extreme variability in faunal density between adjacent stratigraphic layers becomes comprehensible when we recognize that each layer represents fundamentally different depositional events. A single storm could deposit meters of sediment in hours, rapidly incorporating whatever faunal materials were present. The next layer might accumulate over decades with surface stability, concentrating bones from hundreds of meals while also subjecting them to weathering, trampling, and scavenging. These different formation processes create adjacent layers whose faunal densities can differ by orders of magnitude, not because prehistoric diet changed, but because the mechanisms of bone accumulation and preservation varied drastically.
The model also resolves the apparent paradox of greater taxonomic variation within individual sites than between different sites across the island. If cultural preferences or resource availability drove faunal patterns, we would expect other sites to show distinct signatures based on their local environments. Instead, the data reveal more variation between layers at Anakena than between Anakena and sites on different parts of the island.
In light of this depositional framework, we see that marine resources remain dominant throughout the sequence, thus refuting persistent claims of marine resource depletion. If fish and shellfish were becoming scarce, we would expect to see a gradual decline in their representation as islanders turned increasingly to terrestrial alternatives. Instead, marine resources comprise 50-99% of assemblages in well-sampled contexts, regardless of stratigraphic position. Under the episodic deposition model, this consistency reflects the fundamental stability of subsistence practices.
Finally, the strong correlation between sample size and taxonomic diversity emerges naturally from this model of site formation. Rapidly formed deposits preserve limited behavioral episodes and thus contain fewer taxa. Slowly accumulated layers capture more activities over longer time spans and include rare taxa that are only occasionally part of the diet. This relationship between accumulation time, sample size, and diversity is unrelated to changes in diet breadth or resource stress, or depletion. Yet without recognizing the depositional processes at work, archaeologists have consistently misinterpreted this pattern as evidence for changing subsistence. The model thus unifies seemingly disparate observations under a single explanatory framework grounded in the physical processes of landscape change and sediment deposition.
A critical analysis reveals that the integrated Anakena dataset does not indicate a simple, unidirectional decline of wild resources. Instead, it suggests a complex and context-dependent pattern that nonetheless reveals some changes, which we outline here.
Fish remains dominate the assemblages at all time depths, comprising between 60–90% of identified faunal remains by NISP in most layers. There is no evidence of a decrease in fish consumption during the late pre-European contact period. Instead, it appears fish increase in relative importance in later layers as bird numbers decline. Both nearshore species (e.g., reef fishes) and some offshore species are present early on; by late periods, the fish are mostly nearshore (small wrasses, rockfish, etc.), but this shift appears to be gradual. Overall, marine fish remained the staple protein from the initial settlement through European contact, which suggests that marine resource depletion was not a significant issue.
Seabird bones indicate a marked decline over time, confirming that bird exploitation was significantly higher in the earliest period and subsequently decreased. Habitat modification and rats would also have deleterious impacts on ground-nesting seabirds. In Steadman’s lowest layer (early context), seabirds constituted up to 15–20% of the faunal NISP (and a greater variety of species). By late prehistoric times (e.g., upper levels of Hunt & Lipo’s excavation), seabird remains are scarce, often <1% of NISP. This supports the interpretation that breeding seabird colonies were largely wiped out by human predation and predation by rats relatively early. However, it’s important to note that even in early layers, fish remains vastly outnumbered bird remains (on the order of 5:1 or more in NISP), so birds were never the primary food resource but likely a supplementary one. The disappearance of birds would have reduced diet breadth but not eliminated the primary protein source.
Land bird and terrestrial vertebrate remains (excluding commensals) are essentially absent from the earliest contexts. Steadman (2006) recovered bones of small native land birds (now extinct, including rails, herons, and parrots) in the early Anakena strata, but none in the later middens. No indigenous land mammals existed on Rapa Nui, and reptiles played no significant role in the diet. Thus, the terrestrial faunal base was always limited, a point emphasized by Ayres (1985), who noted the “limited land fauna” and consequent reliance on marine food. The loss of land birds, while ecologically significant, likely had a negligible effect on human subsistence given their minor contribution.
Marine mammal remains (chiefly dolphins or small cetaceans) are present in the early Anakena contexts and some late contexts. Our analysis confirms Hunt and Lipo’s observation: bones identified as porpoises or dolphins occur in the upper layers of the 2004–05 excavations in modest numbers. In contrast, Martinsson-Wallin and Crockford reported no sea mammal bones in layers dating after ca. 1400 CE in their excavations. This discrepancy may be due to periodic exploitation of sea mammals, as islanders would have hunted dolphins opportunistically and occasionally. The presence of sea mammals in later deposits weakens the claim of a loss of offshore resource use.
Despite recovery of marine mammal remains in their later deposits, Steadman et al. (1994) claimed that “the abundance of dolphin bones suggests that the prehistoric Rapanui had sailing canoes for hunting dolphins offshore until c. A.D. 1300-1400, deforestation eliminated the raw material (trees) needed to make the canoes.” However, as we pointed out in an earlier analysis (Hunt and Lipo 2009:605), the presence of marine mammal bones does not necessarily indicate a deep-sea fishing strategy. Ethnographic examples document using small canoes in nearshore waters, or simply by swimming, people hunt dolphins by striking stones together in nearshore waters to disorient the animals’ echo-location system, driving them into shallower waters or stranding them on shore where they are killed (e.g., Bloch et al. 1990, Takegawa 1996, Porcasi and Fujita 2000). Sea-mammal bones from Anakena (the only location where they are reported in any quantity for the island) likely represent this specialized capture method. This event occurred at that location in the early twentieth century (Sergio Rapu Haoa, personal communication, 2008). Given that marine mammals do not disappear from the faunal record, it shows that they were not depleted by over-exploitation, nor did people lose access to sea mammals as a result of deforestation. Marine mammals, such as dolphins, were likely taken in occasional drives onto the sandy beach at Anakena, one of the few places on the island where this strategy would be feasible.
Chicken remains are found in both early and late contexts, but their relative frequency increases slightly in later prehistory. In the Anakena sequences, chicken bones constitute only a few percent of faunal remains in early layers and rise to approximately 5–10% of NISP in late layers (this is consistent with ratios reported by Ayres). The slight increase might reflect the relative importance of poultry after wild bird populations were extirpated. The archaeological record suggests that chickens were always a relatively minor component, by bone count, compared to fish. Overall, there may be evidence for somewhat increased use of chickens in late prehistoric diets.
Polynesian rat (Rattus exulans) remains are abundant in all Anakena assemblages; however, their proportional representation over time is variable and does not exhibit a consistent upward trend. If a “fallback food” hypothesis were correct (i.e., as other resources dwindled, people increasingly ate rats), we would expect rat bones to comprise a larger percentage of faunal remains in progressively later layers. Our compiled data do not fit that expectation neatly. In Skjølsvold’s stratigraphy, for example, rat MNI comprised ~7.5% of the early layer fauna but only 0.6% of the later layer, the opposite of a predicted increase. In Steadman’s test pit, the percentage of rat bones oscillated with depth: one of the middle layers (~40–60 cm depth) had the highest rat % (~50% of NISP), while both deeper and shallower layers had lower values (e.g. the lowermost level >120 cm had ~28% rat, and the surface had none, though the surface sample was very small). Hunt & Lipo’s excavation similarly showed fluctuations: some late contexts contained ~20–30% of bones from rats, while others had less than 10%. Many rat bones likely entered the archaeological record not only as food remains but also as evidence of natural deaths, thereby reflecting the population numbers of rats in the environment. In short, the idea that a late prehistoric increase in rat consumption indicates starving people is not suggested by the data. Independent data from human isotopic analysis reveals a similar pattern of higher rat consumption in early periods, followed by a relative decline in later times (Commendador et al. 2013). Rats were a persistent part of the ecosystem (and diet to some extent), and their bones are common from the earliest times. Based on ecological models, we would expect rats, as an invasive species, to follow a boom-and-bust trajectory, and the integrated data may be consistent with a decline in rat populations over time.
Claims that declining marine resource use resulted from palm forest loss and the ensuing inability to build ocean-going canoes (e.g., Steadman et al. 1994; Diamond 2005) overlook the fundamental botanical properties of the extinct palm Paschalococos disperta, likely related to the Chilean wine palm Jubaea chilensis. As monocotyledons, palms differ fundamentally from dicot trees normally used for Polynesian canoe construction. While dicots have uniform density ideal for watercraft, palms consist of a thin, hard outer cortex (5-14% of stem diameter) surrounding soft, parenchymatous tissue with scattered vascular bundles (Ingersoll et al. 2022; Guzmán et al. 2017). Fresh palm stems also contain enormous amounts of moisture, making them denser than water and prone to sinking. Even when dried, palms rapidly absorb water due to their sponge-like structure (Ingersoll et al. 2022). The heterogeneous anatomy creates a structure “much like a hollow barrel with a solid softwood interior” (Gurley & Liller 1997), lacking the uniform integrity needed for seaworthy vessels. Finally, palm wood cannot be shaped using traditional techniques as it would be impossible to shape by adzing, and it exhibits poor dimensional stability.
But among the potentially workable alternatives, the largest native hardwoods (likely including Alphitonia, Elaeocarpus, Pittosporum, Thespesia) reached only 60-80 cm in diameter and were unsuitable for large canoe hulls (Zizka & Zizka 2022; Orliac 1998). Rapa Nui’s limited deep-sea fishing capabilities resulted from inherent wood limitations, not deforestation—suitable canoe-building material likely never existed on the island. Given this lack of appropriate trees, as historical evidence suggests, Rapa Nui’s small canoes were made of non-local materials. Thompson (1891:474) described cave canoes as a “patchwork of several kinds of wood” that “never grew on Easter Island, but had been obtained from drift-wood.”
Our findings fundamentally challenge the empirical basis for collapse narratives on Rapa Nui. Our analysis of faunal assemblages from multiple excavations reveals that, when analyzed with attention to formation processes and sampling effects, the archaeological evidence contradicts, rather than supports, models of catastrophic resource depletion and societal failure.
The most striking finding emerges from the temporal patterns in marine resource exploitation. Throughout the excavation sequences at Anakena, marine resources in general consistently dominate assemblages, typically comprising 50-99% of identifiable fauna when sample sizes are adequate. The Skjølsvold data indicate that use of marine resources increased from 92% to 98% of the assemblage by weight, the opposite of what resource depletion models predict. Rather than abandoning marine resources as they became scarce, the inhabitants of Anakena increased their reliance on them.
The role of shellfish in the pre-European diet provides equally compelling evidence against collapse interpretations. Previous researchers have characterized shellfish as a “fallback” resource, one that is exploited only after preferred foods have become depleted. However, Skjølsvold’s MNI data revealed that shellfish represented 89.4% of individuals in the earlier deposits and 96.8% in the later ones. These numbers demonstrate the intensive and sustained exploitation of a highly productive resource throughout the occupation sequence. Rather than representing desperation, shellfish provided a reliable and abundant food source throughout prehistory.
Exploitation of fish persists throughout all sequences at remarkably consistent levels. When quantified by NISP in well-sampled contexts, fish typically represent 15-35% of assemblages across all excavations. The apparent variation in fish percentages between excavations and stratigraphic levels correlates strongly with recovery methods and quantification systems rather than temporal position. Skjølsvold’s weight-based data show a decrease in fish from 47% to 15% between layers, but a massive increase in shellfish exploitation offsets this apparent decline. The overall pattern suggests consistent fish exploitation, accompanied by an intensification of shellfish gathering.
Our analysis reveals that depositional processes, rather than cultural changes, drive the variability in faunal assemblages that previous researchers have interpreted as evidence for subsistence change. The extreme coefficients of variation documented across all excavations, ranging from 7% to 120%, exceed thresholds that Grayson (1988) established for episodic natural deposition. With deforestation, landscape destabilization created a complex system of erosion and deposition at coastal sites. What might appear as a temporal change in subsistence reflects the differential accumulation of faunal remains under varying depositional conditions.
The influence of methodological factors on assemblage composition cannot be overstated. Screen size variations alone can account for dramatic differences in the representation of small taxa, particularly fish bones. The progression from 6mm screens in early excavations to 3mm screens in later work resulted in increasingly complete recovery of small bones. Different quantification methods compound these effects. A single assemblage can appear dominated by fish when quantified by weight, by shellfish when quantified by minimum number of individuals (MNI), or by rats when quantified by number of identified specimens (NISP). These methodological variations between excavations and analysts have created an artifact that, when viewed uncritically, could support narratives of resource depletion and dietary change. The convergence of evidence from multiple independent lines of analysis suggests a single conclusion: the faunal record from Rapa Nui documents sustained maritime adaptation, rather than depletion of marine resources.
Narratives can become entrenched in interpretive frameworks. Once these narratives take hold, they guide how researchers frame questions, identify patterns, and interpret ambiguous data. The case of Rapa Nui highlights the need for rigorous quantitative analysis that tests competing hypotheses rather than simply reinforcing existing models. Only by explicitly examining alternative explanations, in this case depositional processes and methodological factors, can archaeology move beyond compelling but unsupported narratives toward a more accurate understanding of past human behaviors.
Our analysis demonstrates that widely cited narratives of ecological collapse on Rapa Nui lack empirical support when faunal data are critically analyzed within appropriate methodological and taphonomic frameworks. Rather than indicating depletion-driven subsistence change, the archaeological record reflects a resilient and adaptive maritime economy that persisted throughout the island’s prehistory. By disentangling cultural behavior from the effects of sedimentation, recovery techniques, and quantification methods, we clarify the factors that have contributed to variability in faunal assemblages. Fine screening, stratigraphic control, and the use of appropriate comparative metrics reveal patterns of resource use that remain stable or intensify over time, particularly in relation to marine exploitation.
Future research should prioritize integrative frameworks that link environmental processes, archaeological visibility, and human behavioral ecology. In particular, modeling the relationship between sediment dynamics and faunal deposition can clarify how environmental instability mediates the archaeological record. Comparative studies across Polynesia and beyond should revisit claims of prehistoric subsistence change, particularly those positing resource depletion, with explicit attention to methodological consistency, taphonomic filters, and the potential for equifinality in the archaeological signature of resource use.
Ultimately, Rapa Nui offers a cautionary tale not of collapse, but of interpretive overreach. We argue that a more accurate account recognizes the island’s inhabitants not as victims of ecological disaster, but as agents of strategic adaptation within a challenging and changing environment. Their resilience, rather than their collapse, is a more accurate portrayal.