By its nature, archaeology is concerned with those materials from the past that persist.  To become an artifact useful to archaeologists, a thing must either be made of material that does not decompose or disintegrate, or it must be fossilized or otherwise preserved from the mechanical and chemical processes of wind and water. Cultural chronologies of prehistoric people (e.g., Cultural Chronology) are based largely on inorganic material made of stone or clay (projectile points, grinding implements, pottery) and bone because those are the remnants of a people’s material culture that survive to the present. Use of organic elements, such as plants, can usually only be inferred by assuming some measure of cultural continuity between the historic and the prehistoric. Such assumptions must then be examined in view of new information that may become available.

It is quite certain that from the earliest stages of human occupation on the Snake River Plain, people here were hunters of large game. Lithic tools from the earliest strata of cultural deposition include large spear points that are often associated with the bones of now extinct mammoth, caribou, bison, and horse (Reed et al. 1987:82-108). Grinding implements and pottery, which might indicate the use of plants, are almost entirely absent. The archaeological record indicates a gradual reduction in projectile point size that corresponds roughly with the local or complete extinction of large, relatively slow moving mammals, and their replacement by the swifter-footed, smaller mammals that exist on or about the INEEL today: mountain sheep, deer, elk, and pronghorn. The smaller projectile points are accompanied first by evidence of spear-throwing technology (i.e. the atlatl), and later by evidence of the bow and arrow, both of which seem to be adaptations to the hunting of smaller, faster animals (Ringe 1995).         

Use of plants by prehistoric people is only infrequently indicated by the archaeological record.  Seeds may be found charred in a hearth or adhering to the inside walls of a cooking pot.  They may also be found preserved as they were cached in a sealed container buried for future use. Coprolites, or human feces, are one of the most valuable sources of information about the prehistoric human diet, as indigestible parts of both plant and animal food may be preserved there.  Remnants of wood and brush shelters may be found preserved in very dry climates, or roof support post holes may be discerned from a subsurface change in soil structure and the presence of molds (from decomposing posts) in the soil. The problem for archaeologists on the Snake River Plain is that such examples of preserved organic materials are seldom found in this part of the world. Here, the combination of semi-arid (as opposed to arid) conditions with semi- to fully-nomadic cultures produced an archaeological record that is heavily biased toward the more recalcitrant artifacts: lithic tools and evidence of their manufacture, and the bones of animals brought down by their use. This evidence alone would lead one to believe that the Plain’s prehistoric inhabitants were subsisting chiefly on flesh. 

However, one of the INEEL’s best preserved sites, Aviator Cave (see Map) presents a limited cultural assemblage that provides evidence to the contrary. It includes charred cactus seeds and spines, twined plant fiber, both matted and charred sagebrush, a bunchgrass torn up by the roots and apparently used as a makeshift broom (the stems are evenly worn), and a few fragments of Subalpine Fir needles that must have been transported to the site (perhaps stuck in sap carried as travel food). This site dates to between 1500-300 B.P. (Lohse 1990), and its cultural assemblage can be readily interpreted despite sketchy ethnographic information: cactus stems and fruits were eaten, often after being roasted in a fire; sagebrush was often used for fuel, insulation, or bedding; various kinds of sap were collected and eaten, or carried about as travel food (Steward 1938). Unfortunately, this is one of only a handful of sites on the eastern Snake River Plain containing any ethnobotanical information at all.  Consequently, most of what we can say about prehistoric plant use in this region is conjecture based on ethnographic information, on assumptions of prehistoric-historic cultural continuity, and on models of human nutrition. However, studies of successful hunter/gatherers worldwide suggest that the common pattern is one of primary reliance on plant resources as the dependable source of calories (Lee 1968, Simms 1984).