The alimentary canal of the Siberian chipmunk (Eutamias sibiricus,Laxm. 1769): macroscopic and light microscopic examination

The canalis alimentarius of the Burunduk (Eutamias sibiricus), a rodent belonging to the family Sciuridae, were examined macroscopically (12 animals) and light microscopically (three animals). The esophagus is lined with a stratified non-keratinized squamous epithelium. The one-chambered stomach is of a simple type covered with a glandular mucous membrane. When empty and moderately filled, the stomach looks like a curved sack and lies intrathoracally. The filled stomach extends to the left and ventrally into the regio abdominis media. The greater omentum covers incompletely ventrally and in a part laterally the intestinal mass. The intestinal canal averages about 780 mm in length, that is 6.5 as long as the whole body. The relative length of the small intestine compared with the large intestine is 36-64%. The U-shaped Duodenum is composed of a Pars cranialis, descendens and ascendens and possesses a Plica duodenocolica as well as a Plica duodenocolica accessoria. The Jejunum averages about 420 mm length and is mainly located in the right and ventral part of the regio abdominis media. As in other rodents, the cecum is well developed. The length of the ascending colon averages about the body length and forms an Ansa proximalis and two parallel loops, Ansa media and Ansa distalis coli, both lying in the right Cavum abdominis. Peculiar for the colon are Noduli lymphatici solitarii surrounding cavities lined by a surface epithelium. According to the anatomical structure of the gut and based on physiological diet facts the Burunduk is not a mere herbivore but has to be classified as an omnivore depending upon uptake of animal food protein.