Background: The study of tongue of mammals is important because the different species of animals with different feeding, so the present study was attended to observe the relation between various feeding and the morphological shape of tongue of present stages of both R. rattus and O. cunniculus using histological, histochemical techniques, ultra structural examination and Statistical analysis. Results: The Egyptian herbivorous rabbit O. cunniculus and the rodent R. rattus showed that the tongue is elongated with rounded apex. In both species the thicknesses of the tongue increase gradually toward the pharynx. The tongue length of adult rabbit was large than the adult rat. In the studied animals, the anterior end of the tongue of the herbivorous rabbit O. cunniculus is covered with short horny filiform papillae at the anterior part and giant circumvallate papilla at the posterior part with taste buds, also large enormous numbers of mucus and serous glands but in the rodent Rattus is covered with short pointed horny filiform papillae and others small elongated ones. Few numbers of fungiform papillae and numbers of mucus and serous glands are scattered among the skeletal muscles. The Tongue of adult R. rattus and O. cunniculus have different shapes of filiform papillae, fungiform papillae distributed between the filiform ones, two circumvallate on the surface, number of serrate glands and mucous gland. Give strong reaction with Periodic Acid Schiff (PAS). In young and lactating some undifferentiated and poor developed papillae were observed and serrate and mucous glands less than that in adult stage Conclusion: The different feeding habit of both rat (rodents and Rabbit (herbivorous) give different shapes of papilla and give different reaction with histochemical stains.