Rate of digestion in three species of pinnipeds

Abstract

Torpid bowels or an impaction obstruction significantly retards the rate of passage of digesta in an animal and can lead to serious clinical problems. In many captive animals the approximate rate of food passage is well-known, thus allowing for rapid diagnosis and treatment if an intestinal blockage occurs. Although pinnipeds are commonly kept in captivity, the rate of passage of digesta in these animals is not known. In this study, the time period that elapsed before the initial defecation of a dye-marked meal was determined for 20 pinnipeds representing three species. This initial defecation time (IDT) serves as a good indicator of the rate of passage of digesta. The mean IDTs determined for pinnipeds were very fast averaging 5 h or less. No other medium to large carnivore or omnivore has been shown to exhibit such a rapid rate of passage. The extraordinarily fast excretion rate of these animals is even more remarkable considering that their intestine to body length ratios are among the largest in the animal kingdom. It is hypothesized that the rate of passage of digesta in pinnipeds is strongly influenced by their high metabolic rate and the high water content of their digesta.