. Control of field rodents in California. Rodents; Mammals. -. Fig. 3.—Beechey ground squirrel at entrance to well-used burrow Courtesy of California Forest and Range Experiment Station. the tunnel just above the nest with earth to as much as 3 feet in length and curls up in its nest below the tunnel plug. The burrow entrance remains open. While the squirrel is holed up, the rate of heart beat and respiration are greatly reduced, and the body temperature drops nearly to that of the burrow. The time at which any one squirrel or those in a given locality hole up varies. In the lowlands some ente
. Control of field rodents in California. Rodents; Mammals. -. Fig. 3.—Beechey ground squirrel at entrance to well-used burrow Courtesy of California Forest and Range Experiment Station. the tunnel just above the nest with earth to as much as 3 feet in length and curls up in its nest below the tunnel plug. The burrow entrance remains open. While the squirrel is holed up, the rate of heart beat and respiration are greatly reduced, and the body temperature drops nearly to that of the burrow. The time at which any one squirrel or those in a given locality hole up varies. In the lowlands some enter estivation early in summer, whereas in the high mountains others do not begin hibernation until late in autumn. Emer- gence occurs in late winter or early spring. Estivation ("summer sleep") begins as early as mid-May in the hills east of Livermore, and by late June in the hills of eastern Kern County, whereas it does not commence until early August in Siskiyou County. This habit of estivation explains why old breeding adults suddenly appear in spring, after all squirrels active in a field during fall had been killed and there seemed no chance for migration from the surrounding fields. The exact extent of estivation among our ground squirrels is unknown because it is very difficult to follow an individual squirrel through its activities. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Storer, Tracy I. (Tracy Irwin), 1889-1973. Berkeley, Calif. : College of Agriculture, University of California
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Keywords: ., bookauthorstorertracyitracy, bookcentury1900, booksubjectmammals
