Editing Cetacea (section)

=== Range and habitat ===
{{see also|Cetaceans of the Caribbean}}
Cetaceans are found in many aquatic habitats. While many marine species, such as the [[blue whale]], the [[humpback whale]] and the [[orca]], have a distribution area that includes nearly the entire ocean, some species occur only locally or in broken populations. These include the [[vaquita]], which inhabits a small part of the [[Gulf of California]] and [[Hector's dolphin]], which lives in some coastal waters in New Zealand. Most [[river dolphin]] species live exclusively in fresh water.<ref name=Cassens2000>{{cite journal|last1=Cassens|first1=I.|last2=Vicario|first2=S.|last3=Waddell|first3=V.G.|last4=Balchowsky|first4=H.|last5=Van Belle|first5=D.|last6=Ding|first6=W.|last7=Fan|first7=C.|last8=Mohan|first8=R.S.|last9=Simões-Lopes|first9=P.C.|last10=Bastida|first10=R.|last11=Meyer|first11=A.|last12=Stanhope|first12=M.J.|last13=Milinkovitch|first13=M.C.|title=Independent adaptation to riverine habitats allowed survival of ancient cetacean lineages|journal=Proceedings of the National Academy of Sciences of the United States of America|date=2000|volume=97|issue=21|pages=11343–11347|doi=10.1073/pnas.97.21.11343|pmid=11027333|pmc=17202|bibcode=2000PNAS...9711343C|doi-access=free}}</ref>

Many species inhabit specific latitudes, often in tropical or subtropical waters, such as [[Bryde's whale]] or [[Risso's dolphin]]. Others are found only in a specific body of water. The [[southern right whale dolphin]] and the [[hourglass dolphin]] live only in the [[Southern Ocean]]. The [[narwhal]] and the [[beluga whale|beluga]] live only in the Arctic Ocean. [[Sowerby's beaked whale]] and the [[Clymene dolphin]] exist only in the Atlantic and the [[Pacific white-sided dolphin]] and the [[Lissodelphis borealis|northern straight dolphin]] live only in the North Pacific.{{citation needed|date=October 2024}}

Cosmopolitan species may be found in the Pacific, Atlantic and Indian Oceans. However, northern and southern populations become genetically separated over time. In some species, this separation leads eventually to a divergence of the species, such as produced the [[southern right whale]], [[North Pacific right whale]] and [[North Atlantic right whale]].<ref>{{cite journal|author=AR Hoelzel|title=Genetic structure of cetacean populations in sympatry, parapatry, and mixed assemblages: implications for conservation policy|journal=Journal of Heredity|year=1998|doi=10.1093/jhered/89.5.451|volume=89|issue=5|pages=451–458|doi-access=free}}</ref> Migratory species' reproductive sites often lie in the tropics and their feeding grounds in polar regions.

Thirty-two species are found in European waters, including twenty-five toothed and seven baleen species.{{citation needed|date=October 2024}}