Judith F. Porcasi

The protracted Holocene extinction of California's flightless sea duck (Chendytes lawi) and its implications for the Pleistocene overkill hypothesis

Bones of the flightless sea duck (Chendytes lawi) from 14 archaeological sites along the California coast indicate that humans hunted the species for at least 8,000 years before it was driven to extinction. Direct 14C dates on Chendytes bones show that the duck was exploited on the southern California islands as early as ≈11,150–10,280 calendar years B.P., and on the mainland by at least 8,500 calendar years B.P. The youngest direct date of 2,720–2,350 calendar years B.P., combined with the absence of Chendytes bones from hundreds of late Holocene sites, suggests that the species was extinct by ≈2,400 years ago. Although the extinction of Chendytes clearly resulted from human overhunting, its demise raises questions about the Pleistocene overkill model, which suggests that megafauna were driven to extinction in a blitzkrieg fashion by Native Americans ≈13,000 years ago. That the extermination of Chendytes was so protracted and archaeologically visible suggests that, if the terminal Pleistocene megafauna extinctions were primarily the result of human exploitation, there should also be a long and readily detectable archaeological record of their demise. The brief window now attributed to the Clovis culture (≈13,300–12,900 B.P.) seems inconsistent with an overhunting event.

THE DIABLO CANYON FAUNA: A COARSE-GRAINED RECORD OF TRANS-HOLOCENE FORAGING FROM THE CENTRAL CALIFORNIA MAINLAND COAST

Decades ago the Diablo Canyon site (CA-SLO-2) on the central California mainland revealed one of the oldest and longest sequences (ca. 9400 radiocarbon years ago to contact) of coastal occupation on the shore of the northeastern Pacific. The artifacts from these important deposits were reported in detail by Greenwood (1972), but only a fraction of the sites faunal collections was analyzed in the original site report. Acquisition of 30 additional radiocarbon dates and analysis of the complete vertebrate fauna have produced a coarse-grained record of human foraging on the California mainland from 8300 cal B.C. to cal A.D. 1769. The temporally controlled faunal matrix, constituting one of the largest trans-Holocene records from western North America, speaks in a meaningful way to two significant issues in hunter-gatherer prehistory: early Holocene foraging strategies and economic intensification/resource depression over time. The site’s earliest component suggests a population invested in watercraft and intensely adapted to the interface of land and sea along the northeastern Pacific coastline. While boats were used to access offshore rocks, terrestrial mammals (e.g., black-tailed deer) were also of primary importance. Dominance of deer throughout the Diablo occupations is inconsistent with recent generalizations about big-game hunting as costly signaling in western North American prehistory. Diachronic variation, correlated with superimposed burials that show growth in human populations through the Holocene, includes: (1) modest incremental changes in most taxa, suggesting resource stability and increasing diet breadth; (2) gradual but significant variation in a few taxa, including the flightless duck which was hunted into extinction and eventually replaced by sea otters; (3) punctuated, multidirectional change during the late Holocene related to historic contingencies of the Medieval Climatic Anomaly and protohistoric disruptions.

The dolphin hunters : A specialized prehistoric maritime adaptation in the southern California Channel Islands and Baja California

Synthesis of faunal collections from several archaeological sites on the three southernmost California Channel Islands and one in the Cape Region of Baja California reveals a distinctive maritime adaptation more heavily reliant on the capture of pelagic dolphins than on near-shore pinnipeds. Previous reports from other Southern California coastal sites suggest that dolphin hunting may have occurred there but to a lesser extent. While these findings may represent localized adaptations to special conditions on these islands and the Cape Region, they call for reassessment of the conventionally held concept that pinnipeds were invariably the primary mammalian food resource for coastal peoples. Evidence of the intensive use of small cetaceans is antithetical to the accepted models of maritime optimal foraging which assume that shore-based or near-shore marine mammals (i.e., pinnipeds) would be the highest-ranked prey because they were readily encountered and captured. While methods of dolphin hunting remain archaeologically invisible, several island cultures in which dolphin were intensively exploited by people using primitive watercraft and little or no weaponry are presented as possible analogs to a prehistoric Southern California dolphin-hunting technique. These findings also indicate that dolphin hunting was probably a cooperative endeavor among various members of the prehistoric community.

More on Mollusks: Trans-Holocene Shellfish Exploitation on the California Coast

ABSTRACT Comparing allometrically estimated biomass of shellfish versus vertebrates exploited throughout the Holocene reveals that many coastal Californians relied heavily on readily accessible invertebrates for dietary protein. During the Paleocoastal occupation of the coast, shellfish represented as much as 92% of consumed dietary flesh. Data show that this dependence lessened over time, coinciding with an overall reduction in total quantity of consumed animal flesh. The causes of this change are unclear, but it appears to have begun after 9000 BP and involved a gradual increase in the use of vertebrates for the remainder of the Holocene. Considering the preponderance of shellfish in the diet, the increased use of vertebrates would have done little to compensate for the decline in shellfish biomass, especially considering the growth of coastal populations. To sustain themselves, coastal Californians appear to have increased intake of plant resources.

THE MORRO BAY FAUNA: EVIDENCE FOR A MEDIEVAL DROUGHTS REFUGIUM ON THE CENTRAL CALIFORNIA COAST

A robust collection of mammal, bird, fish, and shellfish remains from an 8,000-year residential sequence at Morro Bay, a small, isolated estuary on the central California coast, shows a strong focus on marine species during the Middle-Late Transition cultural phase (950–700 cal B.P.), which largely coincides with the Medieval Climatic Anomaly (MCA). Previous studies have provided modest evidence for increased fishing and rabbit hunting during the MCA in adjacent regions, but the Morro Bay findings suggest a distinctive marine-focused subsistence refugium during the period of drought. Specifically, the sequence shows striking all-time peaks in marine and estuarine birds, fish NISP/m3, and fish/deer + rabbits during the MCA. Heavy exploitation of fish, aquatic birds, rabbits, and shellfish suggests that the bow and arrow, which seems to have arrived in the area at this time, had little impact on local subsistence strategies. La secuencia residencial de unos 8,000 años de duración procedente de Morro Bay (un pequeño estuario aislado en la costa central de California, Estados Unidos) está compuesta por un gran conjunto faunístico que incluye restos de mamíferos, aves, peces y mariscos. Dicho conjunto faunístico indica una fuerte dependencia de las especies marinas durante la fase cultural de la Transición Media-Tardía (950–700 cal a.P.), la cual coincide plenamente con la anomalía climática medieval (MCA). Algunos estudios previos han mostrado modestas evidencias sobre el incremento de la pesca y la caza de lepóridos durante la MCA en las regiones adyacentes. Sin embargo, en Morro Bay los hallazgos sugieren la presencia de un refugio basado en los recursos marinos a nivel de subsistencia durante el periodo de sequía. Específicamente, la secuencia muestra unos picos nunca antes vistos en el número de especímenes identificados (NISP) por metro cúbico de restos de aves marinas y de estuario, mariscos y peces en proporción a la cantidad de cérvidos y lepóridos durante el MCA. La intensa explotación de la pesca, las aves acuáticas, los lepóridos y los mariscos sugieren que la llegada del arco y la flecha, coincidente con el mismo periodo, tuvo un impacto reducido en las estrategias de subsistencia locales.

Late Holocene Occupational Cycles at Toyon Bay, Santa Catalina Island, Alta California

Abstract Excavated nearly five decades ago, the Toyon Bay site (CA-SCAI-564) on Catalina Island remained undocumented until recently (Radde 2015). Now, working with a retained column sample that yielded more than 12,600 vertebrate specimens weighing more than 2,435 g and more than 4,220 g of shellfish remains, we present a comprehensive archaeofaunal analysis that reveals a cyclic progression of three distinct Late Holocene occupational phases supported by use of diverse fish species and a single shellfish taxon, Megastraea (formerly Lithopoma) undosa (wavy top turban snail). Each occupational phase repeats a pattern of escalating use of fish and the wavy top snail over time, followed by abrupt declines in the use of these resources, signaling the onset of short-term inter-occupational hiatuses. Why each occupational phase declined is not known, nor can the nature of the inter-occupational hiatuses be discerned. However, while the overall pattern of subsistence procurement is the same in each phase, proportional use of the principal resources varies between the occupations, indicating changes over time in resource availability. A variety of warm-water fish species in the archaeofauna suggests that the cyclic occupations might reflect seasonal use of the site or that the hiatuses could have been responses to broader climatic episodes, such as droughts or El Niños that would have had negative effects on the availability of environmentally sensitive taxa. Over-exploitation of the intensively exploited gastropod may also have been a contributing factor in periodic site abandonment.