The anatomy of the Walrus head (Odobenus rosmarus): 5. The tongue and its function in walrus ecology
Kastelein, R.A.; Dubbeldam, J.L.; de Bakker, M.A.G. (1997). The anatomy of the Walrus head (Odobenus rosmarus): 5. The tongue and its function in walrus ecology. Aquat. Mamm. 23(1): 29-47
In: Aquatic Mammals. European Association for Aquatic Mammals: Harderwijk. ISSN 0167-5427; e-ISSN 1996-7292, more
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| Authors | | Top |
- Kastelein, R.A.
- Dubbeldam, J.L.
- de Bakker, M.A.G.
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| Abstract |
The tongues of several walruses were examined in terms of gross morphology, anatomy and histology. Compared to the tongues of other pinnipeds, most of which eat fish, the tongue of the walrus is broad, thick, short and smooth. The tip of the tongue can be rounded or bifid, and tip shape seems to be unrelated to the sub-species, gender or age of the walrus, and to whether it is living or dead. The tongue almost fills the buccal cavity and consists mainly of muscle. When it is retracted and depressed in the buccal cavity, it creates a very low pressure, by means of which the edible parts of bivalve molluscs are extracted from their shells. The dermis of the tongue consists of a thick layer of connective tissue with dermal papillae protruding into a clearly cornified epidermis. Lamellated corpuscles are mostly found just below the epidermis; many are found at the tip of the tongue. The ventral half of the epidermal cones at the tip of the tongue are densely innervated. Fourteen circular protrusions, in the median part of the tongue, have more innervation than the surrounding tissue, and lamellated corpuscles are found directly under them. The tip of the tongue has good tactile sense, and is probably used for identifying objects and for checking the position of bivalve molluscs in the mouth. There are seven circumvallate papillae at the caudal end of the tongue. Compared to many terrestrial mammals, the walrus has relatively few, but large taste buds. Caudal of the circumvallate papillae, fusiform papillae are present in a V-shape, pointing in the caudal direction, which are shorter at the rostral end than at the caudal end. The inside of the fusiform papillae consists of serous glands, and the salivary glands under the papillae are also serous. The tongue of the walrus is adapted to the manipulation of its main prey: bivalve molluscs. |
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