SREL Reprint #0186




Effects of Radiation on Survival of Wild Cotton Rats (Sigmodor Rispidus) in Enclosed Areas of Natural Habitat

Michael R. Pelton and Ernest E. Provost



Each month for 4 successive months 4 groups of wild adult female cotton rats (8 females per group) were irradiated at dose levels of 500, 750, 900, 1050, and 1200 R whole-body.  Treatment was accomplished at 1.5 m using a 9200 Cl137 Cs source at a rate of approximately 20 R per minute.  Each group was released into a one acre enclosure with 4 unirradiated (control) females and 4 untreated males.  Fifteen days later the animals were removed by live and/or snap trapping.  Recapture and survival data on the females were subjected to analysis of variance for the effects of dose level and month, and a field LD50 was determined.  Results of these filed experiments substantiate the high re-dioresistance determined for this species in previous laboratory experiments and aggressive quantitative similarity and qualitative differences in stressors existing between the environments.  A direct correlation was established between dose level and survival with recaptures ranging from 91% at the 500 R level to 25% at 1200R.  Survival was essentially 100% among controls.  No seasonal effects were noted in these experiments.


SREL Reprint #0186

Pelton, M.R. and E.E. Provost. 1969. Effects of radiation on survival of wild cotton rats (Sigmodon hispidus) in enclosed areas of natural habitat. p. 39 45. In Second National Symposium on Radioecology, edited by D.J. Nelson and F.C. Evans. CONF 670503. Ann Arbor, MI.

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