Is chewing efficiency in small herbivorous mammals a function of body size?

Based on the original data on the fractionation of stomach and excrements contents, the effectiveness of the masticatory apparatus and post-gastric transformation of food particles in representatives of small herbivorous mammals is considered. It was found out that in the group of small animals with a body mass from 20 to 200 g the effectiveness of chewing does not depend on the body size but is due to the specifics of the functioning of the chewing apparatus. Particle reduction in this group is masked by a rapid change in digestion regimes, the intensity of nonspecific or specialized coprophagy, and the development of the fiber separation mechanism in the large intestine, which leads to high variability of results. The influence of body size is realized when larger herbivores with a body mass of up to 3–5 kg (hares) and up to 20 kg (beavers) are introduced into the comparison. In this case the influence of body size on the effectiveness of chewing is clearly manifested. In this interaction between the groups of animals, effects similar to those previously established in a wide comparative series of large herbivores with a body mass of up to 3000 kg were revealed. Thus, chewing can be considered as a function of body size, when comparing animals that differ significantly in body mass. Special attention is paid to the fraction of the finest particles, as containing not only fragments of fibers, but also non-food inclusions.