Editing Cetacea (section)

=== Research history ===
{{See also|Cryptid whale|Whale#In myth, literature and art}}

[[File:Trolual (Gessner).jpg|thumb|A whale as depicted by Conrad Gesner, 1587, in ''Historiae animalium'']]
In [[Aristotle]]'s time, the fourth century BCE, whales were regarded as fish due to their superficial similarity. Aristotle, however, observed many physiological and anatomical similarities with the terrestrial vertebrates, such as blood (circulation), lungs, uterus and fin anatomy.<ref>{{Cite book |last=Aristotle |url=https://penelope.uchicago.edu/aristotle/histanimals8.html |title=The History of Animals, Book VIII |language=en |translator-last=Thompson |translator-first=D'Arcy Wentworth |chapter=Chapter 2 |access-date=April 16, 2022 |archive-url=https://archive.today/20220416102355/https://penelope.uchicago.edu/aristotle/histanimals8.html |archive-date=April 16, 2022}}</ref>  His detailed descriptions were assimilated by the Romans, but mixed with a more accurate knowledge of the dolphins, as mentioned by [[Pliny the Elder]] in his ''[[Natural History (Pliny)|Natural history]]''. In the art of this and subsequent periods, dolphins are portrayed with a high-arched head (typical of porpoises) and a long snout. The [[harbour porpoise]] was one of the most accessible species for early [[cetology|cetologists]]; because it could be seen close to land, inhabiting shallow coastal areas of Europe. Much of the findings that apply to all cetaceans were first discovered in porpoises.<ref>{{cite book|author= Conrad Gesner|url=http://etext.lib.virginia.edu/toc/modeng/public/AriHian.html|title=Historiae animalium |date=6 September 2008 |archive-url= https://web.archive.org/web/20080906090248/http://etext.lib.virginia.edu/toc/modeng/public/AriHian.html |archive-date=6 September 2008 |access-date=4 September 2015}}</ref> One of the first anatomical descriptions of the airways of a harbor porpoise dates from 1671 by John Ray. It nevertheless referred to the porpoise as a fish.<ref>{{cite journal|author=J. Ray|title=An account of the dissection of a porpess|journal=Philosophical Transactions of the Royal Society of London|volume=6|issue=69–80|year=1671|pages=2274–2279|bibcode = 1671RSPT....6.2274R|doi=10.1098/rstl.1671.0048|s2cid=186210473|doi-access=free}}</ref><ref>{{cite journal|author=Susanne Prahl|title=Studies for the construction of epicranialen airway when porpoise (Phocoena phocoena Linnaeus, 1758)|journal=Dissertation for the Doctoral Degree of the Department of Biology of the Faculty of Mathematics, Computer Science and Natural Sciences at the University of Hamburg|year=2007|page=6}}</ref>

{{Blockquote|The tube in the head, through which this kind fish takes its breath and spitting water, located in front of the brain and ends outwardly in a simple hole, but inside it is divided by a downward bony septum, as if it were two nostrils; but underneath it opens up again in the mouth in a void.|John Ray, 1671, the earliest description of cetacean airways}}

In the [[10th edition of Systema Naturae]] (1758), Swedish biologist and taxonomist [[Carl Linnaeus]] asserted that cetaceans were mammals and not fish. His groundbreaking binomial system formed the basis of modern whale classification.{{citation needed|date=October 2024}}