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==Paleobiology== Comparisons between the [[sclerotic ring|scleral ring]]s of ''Corythosaurus'' and modern reptiles suggest that it may have been [[cathemeral]], meaning it was most active throughout the day at short intervals.<ref name="Schmitz2011"/> The sense of hearing in hadrosaurids, specifically such as ''[[Lophorhothon]]'', also seems to have been greatly developed because of an elongated [[Lagena (anatomy)|lagena]].<ref name="weishampel1981">{{cite journal|last=Weishampel|first=D.B.|year=1981|title=Acoustic Analysis of Vocalization of Lambeosaurine Dinosaurs (Reptilia: Ornithischia)|url=http://www.hopkinsmedicine.org/FAE/DBWpdf/R3_1981aWeishampel.pdf|journal=Paleobiology|volume=7|issue=2|pages=252β261|jstor=2400478|url-status=dead|archive-url=https://web.archive.org/web/20141006113229/http://www.hopkinsmedicine.org/FAE/DBWpdf/R3_1981aWeishampel.pdf|archive-date=2014-10-06|doi=10.1017/S0094837300004036|bibcode=1981Pbio....7..252W |s2cid=89109302 }}</ref> The presence of a thin [[stapes]] (an ear bone that is rod-like in reptiles), combined with a large [[eardrum]], implies the existence of a sensitive middle ear.<ref name="Schmitz2011"/> It is possible that hadrosaurid ears are sensitive enough to detect as much sound as a modern crocodilian.<ref name="weishampel1981"/> ===Crest function=== [[File:Corythosaurus snorkel.jpg|thumb|Outdated 1916 restoration showing ''C. casuarius'' as semi-aquatic]] The internal structures of the crest of ''Corythosaurus'' are quite complex, making possible a call that could be used as a warning or for attracting a mate. Nasal passageways of ''Corythosaurus'', as well as ''Hypacrosaurus'' and ''Lambeosaurus'', are S-shaped, with ''Parasaurolophus'' only possessing U-shaped tubes.<ref name="weishampel1981"/> Any vocalization would travel through these elaborate chambers and probably get amplified.<ref name="benson2012"/><ref name="ageofdinosaurscorythosaurus"/> Scientists speculate that ''Corythosaurus'' could make loud, low pitched cries "like a wind or brass instrument",<ref name="ageofdinosaurscorythosaurus"/> such as a trombone.<ref name="norrell2000p35"/> The sounds could serve to alert other ''Corythosaurus'' to the presence of food or a potential threat from a predator.<ref name="ageofdinosaurscorythosaurus" /> The nasal passages emit low-frequency sounds when ''Corythosaurus'' exhaled. The individual crests would produce different sounds, so it is likely that each species of lambeosaurine would have had a unique sound.<ref name="norrell2000p35"/> However, even though the range for different lambeosaurine nasal passages vary greatly, they all probably made low-pitched sounds. This might be because low sounds (below 400 [[Hertz|Hz]]) travel a set distance in any environment, while higher sounds (above 400 Hz) have a larger [[Statistical dispersion|spread]] in the distance travelled.<ref name="weishampel1981"/> When they were first described, crested hadrosaurs were thought to be aquatic,<ref name="norrell2000p35"/> an assessment based incorrectly on webbing that is now known to be padding.<ref name="benson2012"/><ref name="brown1916p712"/> The theory was that the animals could swim deep in the water and use the crest to store air to breath. However, it has now been proven that the crest did not have any holes in the end and the water pressure at even {{convert|3|m|ft}} would be too great for the lungs to be able to inflate.<ref name="norrell2000p35">p. 35 in Norrell, M. ''et al.'' (2000).</ref> ===Growth=== [[File:Corythosaurus cauarius, juvenile skull and jaws, Dinosaur Provincial Park, Alberta, Canada, Late Cretaceous - Royal Ontario Museum - DSC00025.JPG|thumb|left|ROM 759, a juvenile skull, originally named as a separate species, ''Tetragonosaurus erectofrons'']] ''Corythosaurus casuarius'' is one of a few lambeosaurines, along with ''Lambeosaurus lambei'', ''Hypacrosaurus stebingeri'', and ''H. altispinus'', to have had surviving fossilized juveniles assigned to it. Juveniles are harder to assign to species because, at a young age, they lack the distinctive larger crests of adults. As they age, lambeosaurine crests tend to grow and become more prominent come maturity. In the Dinosaur Park Formation, over fifty articulated specimens have been found that come from many different genera. Among them, juveniles are hard to identify at the species level. Earlier, four genera and thirteen species were recognized from the formation's area when paleontologists used differences in size and crest shape to differentiate taxa. The smallest specimens were identified as ''Tetragonosaurus'', now seen as a synonym of ''Procheneosaurus'', and the largest skeletons were called either ''Corythosaurus'' or ''Lambeosaurus''. An adult was even identified as ''[[Parasaurolophus]]''.<ref name="evans2005"/> Small lambeosaurines from the [[Horseshoe Canyon Formation]] were referred to ''[[Cheneosaurus]]''.<ref name="evans2005"/> [[File:Parasaurolophus-Corythosaurus-Casuarius growth.png|thumb|300px|Skull growth of ''Parasaurolophus'' sp., ''Corythosaurus casuarius'' and ''Casuarius'' sp. The stars represent the age at which crest development starts]] ''Corythosaurus'' started developing its crest when they were half the size of adults, but ''Parasaurolophus'' juveniles grew crests when they were only 25% as long as adults. Juvenile ''Corythosaurus'', along with adults, had a premaxilla-nasal fontanelle. Young and adult ''Corythosaurus'' are similar to ''Lambeosaurus'' and ''Hypacrosaurus'', but dissimilar to ''Parasaurolophus'' in that the sutures of the skull are sinuous, not smooth and straight. This feature helps to differentiate Parasaurolophini from Lambeosaurini. Generally, the crests of juveniles of lambeosaurines like ''Corythosaurus'', ''Lambeosaurus'', ''Hypacrosaurus stebingeri'', parasaurolophines like ''Parasaurolophus'', and primitive lambeosaurines like ''Kazaklambia'' are quite alike, although other features can be used to distinguish them.<ref name="farke2013">{{Cite journal | last1 = Farke | first1 = A. A. | last2 = Chok | first2 = D. J. | last3 = Herrero | first3 = A. | last4 = Scolieri | first4 = B. | last5 = Werning | first5 = S. | title = Ontogeny in the tube-crested dinosaur ''Parasaurolophus'' (Hadrosauridae) and heterochrony in hadrosaurids | doi = 10.7717/peerj.182 | journal = PeerJ | volume = 1 | pages = e182 | year = 2013 | pmid = 24167777| pmc = 3807589 | doi-access = free }}</ref> Work by Dodson (1975) recognized that there were many less taxa present in Alberta.<ref name="PD75"/><ref name="evans2005"/> ''Tetragonosaurus'' was found to be juveniles of ''Corythosaurus'' or ''Lambeosaurus''. ''T. erectofrons'' was assigned to ''Corythosaurus'' based largely on biometric information. The only non-typic specimen of ''Tetragonosaurus'', assigned to ''T. erectofrons'', was later found to be referable to ''Hypacrosaurus'', although the holotype of the species was still found to be assignable to ''Corythosaurus''.<ref name="evans2005"/> ===Diet=== ''Corythosaurus'' was an ornithopod, therefore being a herbivore. Benson ''et al.'' (2012) realized that the beak of ''Corythosaurus'' was shallow and delicate, concluding that it must have been used to feed upon soft vegetation. Based on the climate of the Late Cretaceous, they guessed that ''Corythosaurus'' would have been a selective feeder, eating only the juiciest fruits and youngest leaves.<ref name="benson2012"/> A ''Corythosaurus'' specimen has been preserved with its last meal in its chest cavity. Inside the cavity were remains of [[conifer]] needles, [[seeds]], [[twig]]s, and [[fruits]], meaning that ''Corythosaurus'' probably fed on all of these, implying that it was a [[Browsing (herbivory)|browser]].<ref name="norrell2000p41"/>
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