The Record of Native People on Gulf of California Islands [No. 201]
KeywordsIndians of Mexico -- Mexico -- California, Gulf of.
Indians of Mexico -- Mexico -- California, Gulf of -- Antiquities.
Seri Indians -- Travel -- History.
Island archaeology -- Mexico -- California, Gulf of.
Islands -- Mexico -- California, Gulf of -- History.
Natural history -- Mexico -- California, Gulf of.
Land use -- Mexico -- California, Gulf of -- History.
Indians of Mexico.
Indians of Mexico -- Antiquities.
Pacific Ocean -- Gulf of California.
MetadataShow full item record
Other TitlesArizona State Museum Archaeological Series No. 201
CitationBowen, Thomas. 2009. The Record of Native People on Gulf of California Islands. Arizona State Museum Archaeological Series No. 201. Arizona State Museum, University of Arizona, Tucson.
AbstractA century ago it was common knowledge among historians and anthropologists with research interests in northwestern Mexico that Indians had inhabited four large islands in the Gulf of California. Three of these islands—Cerralvo, Espíritu Santo, and San José—are in the far southern Gulf off the coast of Baja California. The fourth island, Isla Tiburón, is located on the mainland side more than 400 km to the northwest, in the constricted region of the Gulf known as the Midriff. At the turn of the twentieth century, Isla Tiburón was well known as the homeland of the Seri Indians and was the only Gulf island still inhabited by native people. Since 1900, ethnohistorical and archaeological research has greatly expanded our knowledge of Indians on both sides of the Gulf. Much of that information, however, pertains to the people living on the peninsula and mainland, and touches on the islands only incidentally. Consequently, few historians or anthropologists are aware that Indians made use of many islands in addition to Cerralvo, Espíritu Santo, San José, and Tiburón. Scholars in other fi elds may not even know that there were Indians on the Gulf islands other than Tiburón. This is particularly unfortunate for ecologists because native people have been in the region for thousands of years and may have played a signifi cant role in shaping the island ecosystems we see today. Although indigenous humans were by far the largest native terrestrial mammal on all but two islands, and the most voracious omnivore on all of them, Homo sapiens does not appear on island species lists, and the potential effects of native people on insular ecosystems have seldom been considered. Discoveries made just in the past decade show that researchers in all fi elds have seriously underestimated the extent to which native people made use of the islands. Reports of early Spanish navigators have established the presence of Indians on many islands in addition to the four listed above. Recent archaeological research on several islands, along with fortuitous observations on others, have revealed evidence of native people on islands with no known documentary record of Indians. Chronological data from the southern Gulf establishes a time depth for indigenous people spanning at least ten millennia. New information from Seri oral history alludes to Seri voyages far beyond Isla Tiburón and greatly expands the picture of indigenous people in the Midriff region. Collectively, these results show that the traditional assumption, that most islands were beyond the range of native people, is dead wrong. It is now clear that Indians knew and exploited nearly every signifi cant island in the Gulf. This study reviews the evidence of native people on each of 32 major Gulf islands. The list includes all 22 islands larger than 2 km2 and 10 smaller islands for which some data exist (summarized in Table 3.2). The data are drawn from historical documents, oral history, and the archaeological record. To the extent possible these data are given as quotations from the original sources. Collectively, the evidence suggests that native people were familiar with at least 29 of the 32 islands. For 19 of the islands the evidence can be considered unequivocal, consisting of unambiguous historical documentation, credible oral history, and/or a clear archaeological record. For ten islands there is some evidence of human use, but it is limited, weak, or equivocal, and therefore, in need of corroboration. There are no data of any kind for two islands, and one small island has produced no evidence of native people despite a comprehensive archaeological survey (these data are summarized in Table 4.1). Of course, Indians made greater use of some islands than others. In general, large islands, with a greater diversity of resources (including fresh water), were exploited more than small islands, and several supported permanent or seasonal communities of people. However, native visitors may have been drawn seasonally or intermittently to even very small islands with special resources, such as nesting seabirds, sea lion colonies, concentrations of cactus fruit, and abundant seed crops that appear after a rain. Historic and ethnographic sources show that islands did not need permanent water to sustain native visitors, who were quite capable of bringing water with them, subsisting on temporary water in tinajas, or utilizing water substitutes. Distance was apparently no barrier to native use of islands. The cane balsa was the universal watercraft, and historic sources suggest that balsa traffi c was extensive throughout the Gulf. In the hands of the Indians, the balsa was a swift and seaworthy craft, and navigation was no doubt facilitated by expert knowledge of winds and currents. All but two islands were within a day’s paddle, and in most cases the overwater distance to the more remote islands could have been reduced by island hopping. Although we now know that native people exploited nearly every signifi cant island, we need much more information about the time span over which those visits took place. Indians were certainly making use of many islands during the seventeenth century when European navigators began keeping careful records. Seri oral history fi rmly places Seri ancestors on several Midriff Islands during the nineteenth century and conceivably earlier. Archaeology is potentially capable of extending island chronologies into the prehistoric past, but there has been only limited progress on this front. Fewer than half of the 32 islands considered in this study have been systematically surveyed, and controlled excavations have been conducted on only three islands. Unfortunately, the archaeological record for many islands consists only of surface remains, and includes few or no time-sensitive artifacts or structures, and little or no organic material suitable for radiocarbon analysis. Clovis projectile points from both the Sonora mainland and the Baja California peninsula indicate that humans were present in the Gulf region by 13,000 years ago, which means that native people have been potential island visitors since that time. So far, radiocarbon dates have been secured for only five islands, and for four of these islands the few dates that are currently available all post-date AD 700. However, a series of 179 radiocarbon dates from 40 sites on Isla Espíritu Santo have clearly established this island’s long occupational sequence, which extends from about 9000 BC to the fi fteenth century AD. Although one site on this island produced spectacular radiocarbon ages on shells from approximately 36,550 to greater than 47,500 BP, these shells were probably already ancient when people collected them. During the late Pleistocene and early Holocene it is likely that not all of today’s islands existed, or existed as islands. Some small volcanic islands may not yet have emerged from the sea, while some of today’s islands were connected to the shore by land bridges because sea level was much lower than it is today. Any island without a landbridge connection at that time would have been accessible only by watercraft. These non-landbridge islands should be considered prime places to search for early evidence of navigation. This in turn raises the question of whether initial human entry into the Americas took place by boat along a Pacifi c coastal route, and whether subsequent dispersal involved the Gulf. In most coastal entry and dispersal scenarios, it is assumed that coastally-adapted boat people arriving at the southern tip of Baja California crossed the mouth of the Gulf to the Mexican mainland, making landfall in Sinaloa or even farther south. However, as R. James Hills has pointed out, this is highly unlikely. People arriving at the southern tip of the peninsula would have seen seemingly endless ocean in all directions except along the peninsular coast leading into the Gulf. There would have been no reason for people adapted to coastal resources to set out into an apparently empty sea. Instead, they would have followed the coastline into the Gulf, presumably exploring the islands along the way. The fi rst reasonable place to cross the Gulf would have been the Midriff, where they could have island-hopped to the mainland with no overwater distance exceeding 17 km. In Hills’ scenario, the Gulf would occupy a pivotal position in human dispersal in the Americas, and it is possible that evidence of this process has been preserved on some of the Gulf islands.
Series/Report no.Arizona State Museum Archaeological Series, 201
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THE ISLAND AND MAINLAND BIOGEOGRAPHY OF RESIDENT ROCKY-SHORE FISHES IN THE GULF OF CALIFORNIAThomson, D. A.; Gilligan, Matthew Reid (The University of Arizona., 1980)Resident rocky-shore fishes were quantitatively sampled and visually censused on islands and mainlands in the Gulf of California. Patterns of biogeographic distribution were investigated in relation to the MacArthur-Wilson model of island biogeography, the lottery hypothesis of reef fish community structure. Analyses of the collections show regular patterns of distribution and relative abundance of rocky-shore fishes. Most of the variation in species number and species diversity is explained by latitude and the associated gradient of physical and oceanographic parameters. The correlation of species number and diversity is higher for island than for mainland samples. The best graphical (numerical clustering) evidence of distinct biogeographic regions in the Gulf is obtained using a similarity measure which includes proportional abundance of species (Horn's measure). Groups corresponded to upper, central, and lower Gulf areas. Greater species number, biomass, and numerical (H'(n)) and biomass (H'(b)) species diversity on islands is paralleled by greater water clarity and volume of ocean near collecting sites. This is true for the entire Gulf, the central Gulf, and for Isla San Pedro Nolasco versus the adjacent mainland rocky shoreline in the central Gulf. Community differences between island and mainland areas were greatest in the upper Gulf. 'Gamma' diversity, a proposed measure of community variance (site to site species turnover within habitats) is highest for mainlands and lowest for islands indicating more predictable community species composition on islands. Visual censuses show a good species-area curve for patch reefs and very small nearshore islands and lower species turnover in more exposed near shore habitats. There is a trend toward smaller body size of fishes on islands and an increase in body size with latitude. It is suggested that both phenomena are the result of thermally regulated growth rather than genetic population differences. High endemism in the resident rocky-shore community (the small sedentary, blennioid and gobioid fishes) is attributed to their relatively poorer means of dispersal (demersal eggs and short-lived pelagic larvae) as compared to the more mobile larger resident reef fishes with greater means of dispersal (pelagic eggs and long-lived pelagic larvae). Insular biogeographic processes in marine reef habitats are mediated by physical and biological oceanographic conditions and processes. Distance appears to be no significant barrier to dispersal for Gulf rocky-shore fishes. Immigration rates may be high in rocky habitats in general, but in inshore mainland areas physical and biological disturbance suggest higher extinction rates and consequent lower diversities. The results of these studies do not agree well with either the MacArthur-Wilson model of island biogeography or the lottery hypothesis of reef fish community structure, however, disturbance does seem to play some role in regulating diversity. Considering dispersal and colonization, oceanographic conditions (e.g., water quality, current patterns) may be important ecological factors that influence the evolution of this community.