The role of dietary fiber in dung size of bushy-tailed woodrats, Neotoma cinerea : its potential application to paleoclimatic interpretation

A laboratory study was conducted to examine causes underlying variation in woodrat dung size. Eight bushy-tailed woodrats, Neotoma cinerea , were captured and sequentially fed 2 diets of 46% and 63% neutral detergent fiber (NDF). Dung pellets were collected for 2 days following 7 days of acclimation to each diet. Length and width of oven-dried pellets ranged, respectively, from 8.3 to 10.2 mm and 3.2 to 4.9 mm for diet 1, and 8.9 to 12.4 mm and 3.6 to 4.7 mm for diet 2. Body weight ranged from 232.0 to 504.5 g and did not significantly affect dung size. A series of 2-factor analyses of variance with repeated measures and sequential Bonferroni tests was used to assess the effect of dietary fiber consumption on dung size. An increase in fiber intake led to a significant increase in dung length and dry dung weight but not dung width or body weight. Results suggest a relationship between dung length in prehistoric woodrat middens and changing climate, although the relationship is not clearly understood and needs further evaluation.