Gross Anatomy of the Digestive Tract of the Hawaiian Monk Seal, Monachus schauinslandi

Abstract

The digestive tract of a female juvenile Hawaiian monk seal was dissected and described. Intestine lengths were measured for a total of 19 seals ranging in age from 1 day old to over 10 yr old. Small intestine (SI) lengths were measured for 10 seals and ranged from 7.1 to 16.2 m; mean SI to standard ventral length (SVL) ratio was 7.1 ± 0.9 m. Large intestine (LI) lengths were measured for 11 seals and ranged from 0.4 to 1.2 m; mean LI: SVL was 0.5 ± 0.1 m. Total intestine (TI) lengths were measured for 18 seals and ranged from 7.5 to 18.4 m; total intestine length to SL ratio was 7.9 ± 1.3 m. SI and LI lengths both exhibited a linear relationship relative to SVL, whereas stomach weight: SVL showed an exponential relationship. TI: SVL was significantly smaller than ratios determined for harbor, harp, and northern elephant seals, but was not significantly different from those of crabeater, leopard, and Ross seals. No correlation was seen between gut length and body length for seven species of seals, including the Hawaiian monk seal.