Date of Award

Fall 2007

Document Type


Degree Name

Master of Science (MS)


Biological Sciences



Committee Director

Robert K. Rose

Committee Member

Alan H. Savitzky

Committee Member

Kerry S. Kilburn

Call Number for Print

Special Collections LD4331.B46 W3295 2007


Cotton rats, Sigmodon hispidus, live in oldfields, habitats with a variety of mostly herbaceous plants. Based on other studies, the hispid cotton rat eats predominantly grasses, but grasses rarely are the only food. Fecal samples were collected each month during an ongoing capture-mark-release demographic study of the rodent community at a location in southern Chesapeake, Virginia. In the lab, five fecal pellets per animal were stained, placed on a microscope slide, and covered with starch-gel medium and coverslip. Then a clear nail polish was applied to produce a semi-permanent slide. Using a microscope and a set of reference slides, plant species were identified by their unique micro-anatomical features, including epidermal hairs, trichomes, and stomates. Cotton rats ate a variety of monocots, dicots, pine bark (in certain seasons), and insects (when available). Cotton rats ate significantly greater amounts of monocots in winter and spring, perhaps a response to the need for more calories to compensate for greater heat loss then. In summer and autumn cotton rats expanded their diets to include greater proportions of the more nutritious but harder to digest di cots. Males and nonreproductive females ate significantly more monocots than reproductive females, which consumed significantly more dicots than monocots when breeding.


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