Lions&Prions&Deer Figure 3. Demographic distribution of prion infection among Table Mesa mule deer. (A) Age distributions of prion-infected male and female deer as compared to age distributions of apparently uninfected female and male deer sampled, expressed as the proportion of the total number of deer in respective sex6infection status group that occurred in each age class. (One-year-old deer likely were underrepresented in our sample because we avoided capturing them for use in survival comparisons.) (B) Age class-specific estimates of prion infection prevalence for sampled female and male deer. Bars are +95% binomial confidence intervals of estimated proportions. doi:10.1371/journal.pone.0004019.g003 cause of death was recorded based on established site evaluation procedures. Whenever feasible, deer carcasses were recovered for necropsy or examined in the field to determine cause of death and tissue samples (retropharyngeal lymph node and medulla oblon- gata at the obex) collected. Deer carcasses that were cached and showed evidence that trauma and localized hemorrhage had occurred in musculoskeletal tissue prior to death were classified in the field as mountain lion kills and were not removed from the location where they were found. We used IHC of lymph node and medulla to confirm prion infection and assess disease progression [10,24]. Geographic locations were determined on all marked deer at least once every 15 days ($24 locations/year) to estimate home range and describe movement patterns. Locations were based on PLoS ONE | www.plosone.org 5 December 2008 | Volume 3 | Issue 12 | e4019