Editing Crocodile (section)

====Olfaction====
Crocodilian [[Olfaction|sense of smell]] is also very well developed, aiding them to detect prey or animal carcasses that are either on land or in water, from far away. It is possible that crocodiles use olfaction in the egg prior to hatching.<ref name="Encyclopædia Britannica" />

[[Chemoreception]] in crocodiles is especially interesting because they hunt in both terrestrial and aquatic surroundings. Crocodiles have only one olfactory chamber and the [[vomeronasal organ]] is absent in the adults<ref>{{cite journal | last1 = Hansen | first1 = A | year = 2007 | title = Olfactory and solitary chemosensory cells: two different chemosensory systems in the nasal cavity of the American alligator, Alligator mississippiensis | journal = BMC Neuroscience | volume = 8 | page = 64 | doi = 10.1186/1471-2202-8-64 | pmid = 17683564 | pmc = 1950884 | doi-access = free }}</ref> indicating all olfactory perception is limited to the olfactory system. Behavioural and olfactometer experiments indicate that crocodiles detect both air-borne and water-soluble chemicals and use their olfactory system for hunting. When above water, crocodiles enhance their ability to detect volatile odorants by gular pumping, a rhythmic movement of the floor of the pharynx.<ref>{{cite journal | last1 = Gans | first1 = C. | last2 = Clark | first2 = B. | year = 1976 | title = Studies on ventilation of Caiman crocodilus (Crocodilia: Reptilia) | url =https://deepblue.lib.umich.edu/bitstream/2027.42/21779/1/0000173.pdf | journal = Respir. Physiol | volume = 26 | issue = 3| pages = 285–301 | doi=10.1016/0034-5687(76)90001-3| pmid = 951534 | hdl = 2027.42/21779 | hdl-access = free }}</ref><ref>{{cite journal | last1 = Putterill | first1 = J.F. | last2 = Soley | first2 = J.T. | year = 2006 | title = Morphology of the gular valve of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768) | journal = J. Morphol. | volume = 267 | issue = 8| pages = 924–939 | doi=10.1002/jmor.10448| pmid = 16634086 | s2cid = 21995436 }}</ref> Crocodiles close their nostrils when submerged, so olfaction underwater is unlikely. Underwater food detection is presumably gustatory and tactile.<ref>Schwenk, K. (2008). Comparative anatomy and physiology of chemical senses in nonavian aquatic reptiles. In, ''Sensory Evolution on the Threshold: Adaptations in Secondarily Aquatic Vertebrates''. J.G.M [[Hans Thewissen|Thewissen]] and S. Nummels (Eds). University of California Press, Berkeley. pp. 65–81</ref>