Allometric scaling of rumen–reticulum capacity in white-tailed deer

Scaling of gut capacity with body weight is part of a hypothesis explaining digestive efficiency across the spectrum of body sizes in ruminant species. Larger animals should retain digesta longer because of gut capacity relative to metabolic demands. Interspecific variation in digestive efficiency is an integral part of the Bell–Jarman principle, which is used to explain interspecific resource selection. Intersexual dietary patterns in some size-dimorphic ruminants have been consistent with the Bell–Jarman principle, thus, supporting its extension within species. However, whether the scalar of the intraspecific scaling relationship of the rumen–reticulum (the organs with the largest capacity and where most fermentation occurs) exceeds the likely scalar of the metabolic rate scaling relationship is unclear. I estimated scaling relationships of rumen–reticulum capacity of 103 white-tailed deer Odocoileus virginianus that were stocked into a 214 ha enclosure in central Texas, USA. Rumen–reticulum capacity had allometric scaling relationships (scalar=0.67–0.75) with body weight. Rumen–reticulum scaling in white-tailed deer does not support extending the Bell–Jarman principle to explaining intersexual dietary patterns in size dimorphic ruminants.