An Ecological Study of Neotoma floridana in Oklahoma

Abstract

Habitats, sex ratios, reproductive conditions, and movements of the eastern woodrat (Neotoma floridana) were studied between October 1959 and September 1961 in Payne County, Oklahoma. Woodrats were captured in four different plant associations. Upland woods, riparian woods, savanna-edge, and grass-forb associations, in that order, contained the highest to the lowest densities of woodrats. The sex ratio was 1:1. Litter size varied from 2 to 7 per female and averaged 3.2. The vaginal oriface opened in certain females when they weighed 150 grams and some females were reproducing by the time they weighed 200 grams. Both sexes are apparently capable of breeding throughout favorable years, but reproductive activity is probably curtailed during most winters. Captured woodrats weighed 35 to 425 grams and 58 per cent weighed 200 grams or more. The greatest weight variations occurred in summer populations owing to the large number of young animals in the population. Woodrats initially weighing less than 150 grams gained weight at an average rate of 1.32 grams per day. Males had larger home ranges than females even though they were captured less frequently and though the average number of days between the first and last capture was almost twice as much for females as for males. Males captured 5 to 24 times had an average home range of 0.64 acre compared to 0.41 for females captured the same number of times. About 95 per cent of the woodrats marked disappeared from the study area within one year after their initial capture.