Editing Blue whale (section)

=== Life span ===
Blue whales live around 80–90 years or more.<ref name=Sears_Perr_2009/><ref name=natgeo/> Scientists look at a blue whale's [[earwax]] or ear plug to estimate its age. Each year, a light and dark layer of wax is laid corresponding with fasting during migration and feeding time. Each set is thus an indicator of age.<ref name=Purves_1955>{{cite journal | author1=Purves, P. E. | title=The wax plug in the external auditory meatus of the | journal=Discovery Reports | volume=27 | pages=259–273 | date=1955}}</ref><ref name=Gabriele_etal_2010>{{cite journal | author1=Gabriele, C. M. | author2=Lockyer, C. | author3=Straley, J. M. | author4=Juasz, C. M. | author5=Kato, H. | title=Sighting history of a naturally marked humpback whale (''Megaptera novaeangliae'') suggests ear plug growth layer groups are deposited annually | journal=Marine Mammal Science | volume=26 | issue=2 | pages=443–450 | date=2010| doi=10.1111/j.1748-7692.2009.00341.x | bibcode=2010MMamS..26..443G }}</ref><ref name=Lockyer_1984a>{{cite journal | author1=Lockyer, C. | title=Age Determination by means of the ear plug in baleen whales | journal=Report of the International Whaling Commission | volume=34 | pages=692–696 | date=1984}}</ref> The oldest blue whale found was determined, using this method, to be 110 years old.<ref name=natgeo>{{cite magazine|magazine=[[National Geographic]]|title=Blue whale|url=https://www.nationalgeographic.com/animals/mammals/facts/blue-whale|archive-url=https://archive.today/20220607195937/https://www.nationalgeographic.com/animals/mammals/facts/blue-whale|archive-date=7 June 2022|access-date=3 March 2023}}</ref><ref name=wdc>{{cite web|title=Blue whale|work=[[Whale and Dolphin Conservation]]|url=https://us.whales.org/whales-dolphins/species-guide/blue-whale/|archive-url=https://archive.today/20230303051510/https://us.whales.org/whales-dolphins/species-guide/blue-whale/|archive-date=3 March 2023|access-date=3 March 2023}}</ref> The maximum age of a pygmy blue whale determined this way is 73 years.<ref name=Branch_2008>{{cite journal | author1=Branch, T. A. | title=Biological parameters for pygmy blue whales | journal=International Whaling Commission Document | volume=SC/60/SH6 | page=13 | date=2008}}</ref> In addition, female blue whales develop scars or [[corpora albicantia]] on their ovaries every time they ovulate.<ref name=Perr_Donov_1984>{{cite book | last1=Perrin | first1=W. F. | last2=Donovan | first2=G. P. | chapter=Report of the Workshop | title=Reproduction in whales, dolphin and porpoises | location=Cambridge, UK | publisher=[[International Whaling Commission]] | date=1984 | editor1-last=Perrin | editor1-first=W. F. | editor2-last=Donovan | editor2-first=G. P. | editor3-last=DeMaster | editor3-first=D. P.}}</ref> In a female pygmy blue whale, one corpus albicans is formed on average every 2.6 years.<ref name=Branch_2008/>