Parotid salivary gland of the African elephant (Loxodonta africana): structure and composition of saliva.

Specimens from parotid salivary glands of full-grown elephant (Loxodonta africana) a (n=6) and saliva aspirated from their main excretory ducts were examined macroscopically and microscopically and analyzed biochemically. The composition of the saliva was compared to that of the blood. The parotids (n=12; mean = 7.4 kg) are homocrine and of a seromucous nature. Myoepithelial cells are well-developed along intercalated ducts and their processes extend to proximal portions of allied acini. The saliva is hypotonic and contains relatively low concentrations of sodium and glucose and high concentrations of potassium, urea, calcium and phosphorus. Absence of detectable levels of alpha-amylase negates a digestive role and the voluminous secrete evidently aids swallowing by moisturising and lubricating the large mass of ingested leaves, grass and bark.