Abstract

Comparative morphological and histological features of tongues allow deducing a relationship between their structure and function, as reflected by an animal’s feeding habits. In the present study, the dorsal surface of pigeon’s (granivorous) and egret’s (insectivorous) tongues were studied using scanning electron and light microscopes. Scanning electron microscopic examination of the dorsal surface of pigeon’s tongue revealed many filiform papillae are distributed in definite areas, whereas other fungiform are irregularly scattered in between. However, examination of the egret’s tongue revealed that it is devoid of these two types of papillae. Giant papillae are observed in the posterior part of the lingual body in both pigeon and egret. Histological examination of the dorsal lingual epithelia of the both birds revealed that it consists of stratified squamous epithelium. In the pigeon, the outermost layer consists of shedding cells while in the egret, a thick keratinized layer is observed. A relationship between the histological structure of the lingual epithelium and the development of keratin expression was discussed. The present data revealed that the morphological and histological variations of both tongues may be related to their feeding habits.

Key words: Aves, tongue, lingual papillae, keratinization.