Gross anatomy of the gastrointestinal system of harp seals (Phoca groenlandica)



The gross anatomy of the gastrointestinal system of 12 harp seals (Phoca groenlandica) was investigated. Harp seals have a typical carnivore monogastric stomach. The tissue wet weight of the stomach of harp seals represented 27.01 (S.D. 3.99)% (n= 12) of the total gastrointestinal tract (GI-tract). All animals were killed while resting on the ice, and had empty stomachs, but when expanded with water to a 30cm pressure the stomach contained 0.60 to 1.60 litres, representing 1.00 (S.D. 0.26)% (n= 12) of the body mass. The small intestine ranged in length from 20.44 to 25.32m, being 14.36 (S.D. 1.58) times the body length, and the tissue wet weight constituted 67.61 (S.D. 4.55)% of the total GI-tract (n= 12). Both caecum and colon were short, maximally 5 and 78 cm, respectively, being 0.022 (S.D. 0.005) and 0.38 (S.D. 0.06) times the body length (n= 12). The caecum tissue wet weight was only 0.18 (S.D. 0.04)% of the total GI-tract weight, while the colon tissue wet weight contributed to 5.33 (S.D. 1.19)% (n= 12). It is concluded that harp seals have relatively long intestines compared to minke whales eating a comparable diet in the North Atlantic Ocean.