LAUSR

Accurate estimates of population dynamics play a major role in formulating conservation strategies for Gunnison’s prairie dogs (Cynomys gunnisoni) and other keystone species. Over 5 years (2014–2018) at Valles Caldera National Preserve in NM, USA, we used a portable ultrasound machine (PUM) to investigate the presence or absence of pregnancy, and to determine uterine litter size for 238 pregnant female Gunnison’s prairie dogs from two colonies. We compared litter size at weaning for 168 of these 238 females and we found no significant difference between uterine litter size and litter size at weaning. For 76 of these 168 females (45%), estimates of uterine litter size and litter size at weaning were identical. We detected no significant variation among years for uterine litter size versus litter size at weaning. To our knowledge, our research is the first to compare uterine litter size to litter size at weaning for the same group of females living under natural conditions.