Lizard Taste and Smell

Lizards have recourse to three main chemosensory systems: vomeronasal, olfactory and gustatory.

The taste buds are poorly developed and are mainly found in the pharynx, tongue and oral epithelium (beneath and lateral to the tongue). They are more abundant in species with fleshy tongues such as the Iguanidae family, reduced in those with keratinized tongues and absent in Varanus indicus (Mangrove monitor - Varanidae family).

Chemoreception

Due to insufficient data, it is difficult to distinguish between taste and vomeronasal function when studying chemosensory-mediated behaviour in lizards.

• Protusion of the tongue or "tongue flicking", although poorly understood in lizards, seems to be primarily for bringing scent particles to the Jacobson's (vomeronasal) organ for olfaction. The vomeronasal system is a specially modified and highly developed olfactory pit located in the roof of the mouth and innervated by a separate branch of the olfactory nerve. Scent particles picked up from the surroundings by the tongue are conveyed to the palate, to pass up through a duct into Jacobsons organ for 'tasting'. Paired internal nares open just caudal to the tiny openings of the paired vomeronasal organs.

• Chemical senses are important in the ecology of squamate reptiles. Chemoreception helps mediate the choice and location of prey, individual recognition, choice and location of a mate, exploratory behaviour, identification of surroundings, courtship and copulatory behaviour as well as all other aspects of social behaviour.

References

• Mader, D.R. (2005). Reptile Medicine and Surgery. Saunders. pp. 1264. ISBN 072169327X
• Schwenk, K. (1985). Occurrence, distribution and functional significance of taste buds in lizards. Copeia 1, 91-101
• Schwenk, K. (1995). Of tongues and noses: chemoreception in lizards and snakes. Trends in Ecology and Evolution 10, 7-12