Editing Nautilus (section)

===Reproduction and lifespan===
Nautiluses reproduce by laying [[egg (biology)|egg]]s. Gravid females attach the fertilized eggs, either singly or in small batches, to rocks in warmer waters (21–25 Celsius), whereupon the eggs take eight to twelve months to develop until the {{convert|30|mm|adj=on}} juveniles hatch.<ref>{{cite book |last1=Hanlon |first1=Roger T. |last2=Messenger |first2=John B. |title=Cephalopod Behaviour |date=1998 |publisher=Cambridge University Press |location=Cambridge, UK |isbn=9780521645836 |page=178}}</ref> Females spawn once per year and regenerate their [[gonad]]s, making nautiluses the only cephalopods to present [[iteroparity]] or [[polycyclic spawning]].<ref>{{Cite journal | last1 = Rocha | first1 = F. | last2 = Guerra | first2 = Á. | last3 = González | first3 = Á. F. | doi = 10.1017/S1464793101005681 | title = A review of reproductive strategies in cephalopods | journal = Biological Reviews of the Cambridge Philosophical Society | volume = 76 | issue = 3 | pages = 291–304 | year = 2001 | pmid =  11569786| s2cid = 5777682 }}</ref>

Nautiluses are [[sexual dimorphism|sexually dimorphic]], in that males have four tentacles modified into an organ, called the "[[spadix (zoology)|spadix]]", which transfers sperm into the female's mantle during mating. At sexual maturity, the male shell becomes slightly larger than the female's.<ref name="Bruce Saunders1978">{{Cite journal | last1 = Bruce Saunders | first1 = W. | last2 = Spinosa | first2 = C. | title = Sexual Dimorphism in Nautilus from Palau | journal = Paleobiology | volume = 4 | issue = 3 | pages = 349–358 | year = 1978 |jstor=2400210| doi = 10.1017/S0094837300006047 | bibcode = 1978Pbio....4..349S | s2cid = 85899974 }}</ref> Males have been found to greatly outnumber females in practically all published studies, accounting for 60 to 94% of all recorded individuals at different sites.<ref name="Dunstan et al. 2011" />

The lifespan of nautiluses may exceed 20 years, which is exceptionally lengthy for a cephalopod, many of whom live less than three even in captivity and under ideal living conditions.<ref>{{cite journal |author=Saunders WB |title=Nautilus Growth and Longevity: Evidence from Marked and Recaptured Animals |journal=Science |volume=224 |issue=4652 |pages=990–992 |date=June 1984 |pmid=17731999 |doi=10.1126/science.224.4652.990 |bibcode = 1984Sci...224..990S |s2cid=40891271 }}</ref> However, nautiluses typically do not reach sexual maturity until they are about 15 years old, limiting their reproductive lifespan to often less than five years.<ref name="Dunstan et al. 2011">{{cite journal |last1=Dunstan |first1=A.J. |last2=Ward |first2=P.D. |last3=Marshall |first3=N.J. |date=February 2011 |editor1-last=Solan |editor1-first=Martin |title=''Nautilus pompilius'' life history and demographics at the Osprey Reef Seamount, Coral Sea, Australia |journal=PLOS ONE |volume=6 |issue=2 |pages=e16312 |pmid=21347356 |pmc=3037366 |bibcode = 2011PLoSO...616312D |doi=10.1371/journal.pone.0016312 |doi-access=free }}</ref>

''Nautilus'' male has a reproductive organ named [[Van der Hoeven's organ]]. ''Nautilus'' female has two reproductive organs whose functions are unknown, the [[Organ of Valenciennes]] and [[Owen's laminated organ]].<ref name="Willey1902">{{cite book |author=Arthur Willey |url=https://books.google.com/books?id=Jwo4AQAAMAAJ&pg=PA778 |title=Zoological Results Based on Material from New Britain, New Guinea, Loyalty Islands and Elsewhere: The anatomy and development of Peripatus novae-britanniae |publisher=University Press |year=1902 |pages=778–9}}</ref>

{{multiple image
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| footer = '''Left:''' Frequency distribution of ''N. pompilius'' shell diameter at [[Osprey Reef]], part of the [[Coral Sea Islands]], based on  2067 captured individuals. Shells ranged in size from 76 to 145&nbsp;mm, with a mean of 128.6±28.01&nbsp;mm.<ref name="Dunstan et al. 2011" /><br/>
'''Right:''' Shell diameter of mature male and female ''N.&nbsp;pompilius'' caught at Osprey Reef. Males (''n'' = 870) had a mean shell diameter of 131.9±2.6&nbsp;mm, compared to 118.9±7.5&nbsp;mm in females (''n'' = 86). The Osprey Reef ''N.&nbsp;pompilius'' population is the second smallest known in terms of mean shell diameter, after the dwarf form from the [[Sulu Sea]] (130.7&nbsp;mm and 115.6&nbsp;mm, respectively).<ref name="Dunstan et al. 2011" />
| image1 = Size frequency distribution for Nautilus pompilius at Osprey Reef.png
| image2 = Sexual dimorphism in mature male and female Nautilus pompilius.png
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