About

Michael Glassow is a Professor Emeritus in the Department of Anthropology at the University of California, Santa Barbara. His specialization includes archaeology and cultural ecology, with a focus on the prehistory of the Santa Barbara Channel region, particularly between 7,000 and 5,000 years ago. His research investigates how populations adapted to changing environmental conditions, emphasizing subsistence practices and settlement patterns. Much of his fieldwork has been conducted on Santa Cruz Island, along with investigations of coastal and inland sites on the mainland, and recent participation in a project on Santa Barbara Island. Professor Glassow's work involves the analysis of archaeological collections from Santa Cruz Island and the mainland, often with the assistance of students in laboratory practicum courses. He is also engaged in editing a volume of papers related to the archaeology and prehistory of the area surrounding the ancient estuary of the Goleta Slough. His contributions to the field include numerous publications on topics such as settlement systems, subsistence and settlement change, shellfish utilization, and archaeological methodologies in California. His research provides significant insights into human-environment interactions and prehistoric adaptations in western North America.

Research topics

• Archaeology
• Geography
• History
• Geology
• Ecology

Selected publications

• Issues in Understanding Interior Settlement during the Period of Red Abalone Middens on Santa Cruz Island

  Western North American Naturalist · 2025-05-27

  article1st authorCorresponding

  Los yacimientos en el oeste de la isla Santa Cruz, que datan entre 7000 y 5300 años, suelen contener llamativas conchas de abulón rojas, a pesar de que los fragmentos de conchas de mejillón son más abundantes. La mayoría de los yacimientos identificados al principio se encontraban en la costa o cerca de ella, pero en los últimos 30 años también se han documentado en lugares tierra adentro que ofrecen la oportunidad de aprender acerca del uso de los recursos alimentarios y la importancia de los recursos alimentarios costeros mientras se vive tierra adentro. Aunque, el muestreo a pequeña escala en algunos de los sitios tierra adentro se llevaron a cabo principalmente con el propósito de obtener muestras para la datación de radiocarbono, más recientemente se han excavado pozos de prueba a mayor escala en cuatro de ellos para obtener muestras lo suficientemente grandes como para evaluar cómo se articulaban los sitios con los sistemas de asentamiento. Los sitios que se encuentran tierra adentro de este período suelen presentar un área pequeña y están ubicados en una variedad de características topográficas. Algunos están enterrados bajo depósitos posteriores y otros pocos poseen estratos asociados que contienen conchas de abulón rojo. Los datos disponibles, aunque aún escasos, indican que pequeñas unidades sociales ocuparon sitios tierra adentro durante algunas semanas o meses seguidos, aparentemente para adquirir y consumir recursos alimenticios vegetales. Se necesitará mayores esfuerzos para localizar e investigar sitios tierra adentro durante el período 7000–5300 AP para crear una idea más clara.

  PublisherDOI

• Occupation of Western Santa Cruz Island’s Interior Between 4,700 and 3,200 B.C.

  California Archaeology · 2021-01-02 · 5 citations

  article1st authorCorresponding

  Investigations of two inland sites on western Santa Cruz Island containing red abalone (Haliotis rufescens) midden strata provides insight into aspects of settlement systems between 4,700 and 3,200 B.P. Oxygen isotope analysis of mussel (Mytilus californianus) shells revealed that both sites were occupied during the summer and fall. Artifacts and floral and faunal remains indicate that CA-SCRI-796 probably was a residential base whereas CA-SCRI-758 was a camp. The red abalone midden at CA-SCRI-758 is distinctive, given the site’s high-elevation location, its location more than 6 km from a source of red abalone, and its thoroughly burned shell within an ashy matrix. The site may have been occupied by separate residential groups for social and ritual purposes. The analysis reveals that settlement systems of the time period during which red abalone middens were created were complex and that larger samples from sites are necessary for a greater understanding of this complexity.

  PublisherDOI

• Small Islands and Marginality: Santa Barbara Island and its Role in the Prehistory of California’s Channel Islands

  Journal of Field Archaeology · 2019-09-19 · 8 citations

  article

  As the smallest of California’s Channel Islands, Santa Barbara Island has received limited attention from archaeologists. A United States National Park Service project designed to assess its 19 known sites evolved into an island-wide survey that increased the number to 63 sites that date between 4000 and 600 years ago. Most are small shell and lithic scatters, although some are larger shell middens with greater faunal and artifact diversity. Their constituents and geographic distribution indicate that the island not only served as a stopover during inter-island travel but was occupied for longer periods to target local resources such as marine mammal rookeries. Our research presents an opportunity to evaluate the significance of this island to prehistoric communities throughout the archipelago. On a broader level, it provides insights into the important roles that small islands have played in prehistoric lifeways as well as perceptions of marginality.

  PublisherDOI

• Differences in Human Population Density between the California Islands and the Coastal Mainland

  University Press of Florida eBooks · 2019-02-26 · 3 citations

  book-chapter1st authorCorresponding

  If the California Islands were marginal environments for the indigenous people who occupied them, human population densities on the islands should be significantly lower than the adjacent mainland coast. Reconstructing population densities at particular times in the past is fraught with methodological difficulties, but data from site sizes and densities, radiocarbon date distributions, and mission records give no indication that island population densities were significantly lower than along the coastal mainland. Population density measures provide little evidence of environmental marginality on the Northern Channel Islands. Human population densities on islands further south may have been lower than the northern islands, but do not appear to have been significantly different than the adjacent mainland coast.

  PublisherDOI

• Seasonal Mobility Patterns During the Middle Holocene on Santa Cruz Island, California

  The 82nd Annual Meeting of the Society for American Archaeology · 2018-01-01

  article1st authorCorresponding
  Publisher

• Prehistoric Shellfish Utilization and Settlement Systems on Western Santa Cruz Island

  Western North American Naturalist · 2018-11-01 · 4 citations

  article1st authorCorresponding

  Archaeologists generally have not taken advantage of the distinctive characteristics of assemblages of shellfish remains from prehistoric sites to gain information about movement of people between sites within their territory. I attempt to demonstrate this potential through analysis of shell assemblages obtained through small-scale test excavation at 2 archaeological sites in the interior of Santa Cruz Island: CA-SCRI-796 in the western sector of the island and CA-SCRI-758 at an upland location in the central sector. An aspect of the data analysis focused on strata containing an abundance of red abalone shells, dating sometime between 3700 and 3350 cal BC at CA-SCRI-796 and sometime between 4900 and 4325 cal BC at CA-SCRI-758. Also considered are assemblages from later strata at CA-SCRI-758, dating between 2600 and 1600 cal BC. Alternative hypotheses to account for the differences between the sites in proportions of shellfish taxa represented are the following: differences in proportional abundances of taxa at the localities where site inhabitants collected shellfish, changes over time in the character of shellfish communities, different distances of the sites from sources of shellfish, and variation in the intensity of shellfish collecting. The first alternative appears to account for most of the differences between assemblages, thus providing information about the geographic extent of settlement systems.

  PublisherDOI

• Maritime to Mountains: Investigation of a Buried Site in the Upper Santa Ynez River Watershed, Santa Barbara County, Alta California

  California Archaeology · 2017-01-02

  article

  Few sites dating to the Early Period are found in the interior of Santa Barbara County. Most are defined by their assemblages of milling stones. CA-SBA-3950, however, has been dated by accelerator mass spectrometry and radiometric dating to about 6,900–6,100 cal B.P. It is a buried deposit composed almost exclusively of marine and estuarine shell. A recent investigation of the site entailed exposure of a profile revealing cultural deposits occurring in two strata that were collectively 140 cm thick. Separate soil movement events capped each stratum. Radiocarbon dates resulting from this investigation better define the time range represented and have implications for the early inclusion of both coastal and interior landscapes within the subsistence and settlement system of the early part of the middle Holocene.

  PublisherDOI

• Historical ecology and the conservation of large, hermaphroditic fishes in Pacific Coast kelp forest ecosystems

  Science Advances · 2017-02-02 · 59 citations

  articleOpen access

  ) has become a complex, multimillion-dollar industry. The fishery is of concern because of high harvest levels and potential indirect impacts of sheephead removals on the structure and function of kelp forest ecosystems. California sheephead are protogynous hermaphrodites that, as predators of sea urchins and other invertebrates, are critical components of kelp forest ecosystems in the northeast Pacific. Overfishing can trigger trophic cascades and widespread ecological dysfunction when other urchin predators are also lost from the system. Little is known about the ecology and abundance of sheephead before commercial exploitation. Lack of a historical perspective creates a gap for evaluating fisheries management measures and marine reserves that seek to rebuild sheephead populations to historical baseline conditions. We use population abundance and size structure data from the zooarchaeological record, in concert with isotopic data, to evaluate the long-term health and viability of sheephead fisheries in southern California. Our results indicate that the importance of sheephead to the diet of native Chumash people varied spatially across the Channel Islands, reflecting modern biogeographic patterns. Comparing ancient (~10,000 calibrated years before the present to 1825 CE) and modern samples, we observed variability and significant declines in the relative abundance of sheephead, reductions in size frequency distributions, and shifts in the dietary niche between ancient and modern collections. These results highlight how size-selective fishing can alter the ecological role of key predators and how zooarchaeological data can inform fisheries management by establishing historical baselines that aid future conservation.

  PublisherOA PDFDOI

• Santa Barbara Island: insights into the prehistory of California’s Channel Islands through its smallest island

  The 81st Annual Meeting of the Society for American Archaeology · 2017-01-01

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• Reply to Braje and Erlandson

  American Antiquity · 2016-07-01 · 2 citations

  article1st authorCorresponding

  Although Braje and Erlandson express concern with my inclusion of Santa Cruz Island sites containing small quantities of red abalone shells with red abalone middens on the other Channel Islands, doing so is justified because of the discrete period of time during which they occur. They also feel that I should have expanded the scope of my paper to include consideration of relationship between sea otters and red abalone, but this was beyond the intent of my report. Nonetheless, I point out that more explication is needed of the nature of sea otter hunting if its effects on red abalone availability are to be understood.

  PublisherDOI

Frequent coauthors

• Jon M. Erlandson

  University of Oregon

  7 shared

• Terry L. Joslin

  5 shared

• Jennifer E. Perry

  California State University, Channel Islands

  5 shared

• Torben C. Rick

  National Museum of Natural History

  5 shared

• Heather B. Thakar

  4 shared

• Todd J. Braje

  University of Oregon

  3 shared

• Steven Craig

  Baker Hughes (United States)

  2 shared

• Michael E. Perez

  2 shared

Education

• Ph.D., Anthropology

  University of California Los Angeles