In reptiles, the nasal chamber is generally larger, with the choanae being located much further back in the roof of themouth. In crocodilians, the chamber is exceptionally long, helping the animal to breathe while partially submerged. The reptilian nasal chamber is divided into three parts: an anterior vestibule, the mainolfactory chamber, and a posterior nasopharynx. The olfactory chamber is lined by olfactory epithelium on its upper surface and possesses a number of turbinates to increase the sensory area. Thevomeronasal organ is well-developed in lizards and snakes, in which it no longer connects with the nasal cavity, opening directly into the roof of the mouth. It is smaller in turtles, in which it retainsits original nasal connection, and is absent in adult crocodilians.
Birds have a similar nose to reptiles, with the nostrils being located at the upper rear part of the beak. Since they generallyhave a poor sense of smell, the olfactory chamber is small, although it does contain three turbinates, which sometimes have a complex structure similar to that of mammals. In many birds, includingdoves and fowls, the nostrils are covered by a horny protective shield. The vomeronasal organ of birds is either under-developed or altogether absent, depending on the species.
Elephants haveprehensile noses.
The nasal cavities are exceptionally large in most mammals, typically occupying up to half the length of the skull. In some groups, however, including primates, bats, and cetaceans, thenose has been secondarily reduced, and these animals consequently have a relatively poor sense of smell. The nasal cavity of mammals has been enlarged, in part, by the development of a palate...