ELLIOTT ET AL.: THE CAVE FAUNA OF CALIFORNIA 
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Epigean: An adjective used to describe the epigeum (surface environment), as opposed to the hypogean (sub¬ 
terranean) environment. 
Epigeum: The surface environment. 
Epikarst: The upper zone of a karst area that extends downward as sinkholes, fractures, fissures, and other 
surface karst features to where the natural porosity of the bedrock is located. Epikarst can range from 
almost nonexistant to tens of meters deep. 
Fault: A planar rock fracture which shows evidence of relative movement of the opposite sides. 
Food chain: A series of plants and animals linked by their food relationships; the passage of energy and mate¬ 
rials from producer through a succession of consumers. Green plants, plant-eating insects, and an insect¬ 
eating bat would form a simple food chain. See also Food web. 
Food pyramid: The normally diminishing number of individuals and amount of organic material produced at 
each successive level along a food chain. The declining productivity at each level results from the con¬ 
stant loss of energy in metabolism as the energy passes along the chain. See also Trophic levels. 
Food web: An interlocking system of food chains. Since few animals rely on a single food source and since 
no food source is consumed exclusively by a single species of animal, the separate food chains in any 
natural community interlock and form a web. 
Formation: A distinct layer of rock from one geologic period, such as the Calaveras Formation. Also a term 
commonly used for a speleothem. 
Fossil: Any remains or traces of animals or plants that lived in the prehistoric past, whether bone, cast, track, 
imprint, pollen, or any other evidence of their existence. 
Geological map: A map that shows the kinds of rock lying beneath the soil or reaching the surface in a given 
area. A topographic map shows the contour or elevation lines, and surface features such as watercours¬ 
es. 
Geology: The scientific study of the earth and the rocks that form it. A scientist who specializes in this study 
is a geologist. 
GIS: Geographic information system, a computer program used for mapping with geographic coordinates. 
Guano: Excrement, as of bats, crickets, or sea birds. In certain bat caves and on islands colonized by sea birds, 
guano sometimes accumulates in such vast quantities that it is m in ed commercially for fertilizer. 
Groundwater: Water that collects underground in soil spaces, bedrock pores and cracks, constituting a sub¬ 
terranean habitat in which life flourishes. California is the single largest user of groundwater in the 
nation. 
Habitat: The immediate surroundings (living place) of a plant or animal; everything necessary to life in a par¬ 
ticular location except the organism itself. 
Herbivore: An animal that eats plants, thus making the energy stored in plants available to carnivores. See 
also Carnivore; Insectivore; Omnivore. 
Herps, herpetofauna: Amphibians and reptiles. 
Hibernation: A prolonged dormancy or sleeplike state in which animal body processes such as heartbeat and 
breathing slow down drastically and the animal neither eats nor drinks. Nearly all cold-blooded animals 
and a few warm-blooded animals hibernate during the winter in cold climates. Extremely large aggrega¬ 
tions of bats, crickets, and spiders hibernate in some caves. 
Holocene Epoch: The name given to the last 11,700 years of the Earth’s history — the time since the end of 
the last major glacial epoch, or “ice age.” The current epoch of the Quaternary Period following the Pleis¬ 
tocene Epoch. 
Humidity, relative: The ratio, expressed as a percentage, of the amount of water vapor actually present in air 
of a given temperature, as compared with the greatest possible amount of water vapor that could be pres¬ 
ent in air at that temperature. Calculation of relative humidity can be done from tables, special slide rules 
or calculators, graphs, or complex equations. See also Hygrometer and Psychrometer. 
Hygrometer: An instrument that reads the humidity in the air directly; some are based on a hair’s ability to 
shrink or expand with humidity, or on certain electronic chips. Generally, a psychrometer is more accu¬ 
rate at higher humidities (above 95%). See also Psychrometer. 
Hypogean: An adjective for the hypogeum (cave environment), as opposed to surface (epigean) and endo- 
gean environments. 
