Abstract
Ruminants were categorized into three feeding types: grazers, mixed feeders and browsers based on their food habits. We studied how phylogeny constrains the feeding types, the morphology of digestive organs, and their relationships in Cervidae and Bovidae. It is shown that species with different feeding types occur in the same phylogenetic group of the family, subfamily, and tribe. This suggests that phylogeny does not always reflect feeding type. Comparisons of three morphological indices of digestive organs (parotid gland size, rumino-reticulum capacity, and rumino-reticulum contents weight) among feeding types found that trends along the grazer-browser continuum were similar in both families. The index values of the same feeding types were similar in the two families. These results suggest that the morphology of digestive organs is closely related to feeding types, and that phylogenetic characteristics are less important. The species in the same feeding type also share other morphological characteristics of digestive organs, irrespective of phylogeny.
