The surface of the avian tongue, as in mammals, is covered by
keratinized stratified squamous epithelium. There are no sensory
papillae to correspond to the vallate, fungiform, and foliate
papillae of mammals, but a large filiform papilla is present in this
field.
One of the lingual salivary glands is also present, and glands of identical appearance are found embedded in the walls of the oral cavity. Birds do have need of some lubrication of their food in swallowing, though not perhaps as much as mammals do.
Avian tongue, decalcified; H&E stain, paraffin section, 20x
