Functional-Morphology of the Alimentary-Tract of the Australian Sea-Lion, Neophoca-Cinerea

Abstract

The form and topographic relationships of the alimentary tract of Neophoca cinerea is described based on dissection and radiography. A highly distensible oesophagus enters the dorsum of a large J-shaped stomach. The small intestine is long, circa 20 m, and the large intestine short, circa 1.2 m. Marker pellets (approximate diameter 1 or 3 mm) administered orally were generally found in faecal deposits containing, principally, coarse particles, i.e. of diameter greater than 1.2 mm. Most faecal deposits consisted of fine particles, i.e. with a diameter primarily of less than 1.2 mm. About 50% of the large markers remained in the alimentary tract for more than 6 days. A pyloric torus acting in concert with the patterns of pyloric peristalsis may prevent or restrict the passage of markers through the pyloric canal. Examination of the stomach contents from six animals showed that items of low digestibility, such as squid beaks and crayfish exoskeletons, were retained in the pyloric antrum.