The tongue-vomeronasal transfer mechanism in snakes

Micron, VoL:12, No.3, pp.299-300,

0047-7206/81/030299-02502.00/0

1 9 8 1

Printed in Great Britain.

01981 Pergamon Press Ltd.

The Tongue-Vomeronasal Transfer Mechanimu in Snakes

David L. Clark Department of Biology Central Michigan University Mr. Pleasant, Michigan 48859

The role of the snake tongue in chemosensation has long been established and its in~portance in predatory, reproductive and aggressive behaviors has been well documented. However, the exact mechanis~ of transfer of envlror~nental chemical information to Jacobson's (vomeronasal) organ has not been substantiated. The literature speculates that the tongue itself makes the transfer through the insertion of the tongue tips into the internal lumen of the vomeronasal organ. Paired anterior processes in the floor of the rat snake's (Elaphe) mouth have recently been identified ( G i l l i r ~ and Clark, 1981, Can. J. Zool. ) These elevate followir~ each tongue retraction (Fig. i). Scanning electron microscopic examination reveals the process' size Is slightly smaller than the duct to the vomeronasal organ and the bifurcate tongue makes ventral contact with these processes on retraction. Each process is thrown into transverse folds and at higher magnifications sagittal and parasagittal pores are found on these ridges, possibly as openings to mucus glands beneath. This represents strong evidence that the anterior processes pick up chemical information from the tongue and mediate the final transfer to Jacobson's (vomeronasal) organ.

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David L. Clark

Fig. I.

Scanning electron micrograph of in situ anterior processes (AP) of the

Black Rat Snake (Elaphe obsoleta) position.

with tongue tips in partially retracted