Editing Vampire squid (section)

===Life cycle===
[[File:Vampyroteuthis1.jpg|thumb|Dissected adult (center) and two immature specimens]]
If hypotheses may be drawn from knowledge of other deep-sea cephalopods, the vampire squid likely reproduces slowly by way of a small number of large eggs, or a [[K-selected#K-selection|K-selected]] strategy. Ovulation is irregular and there is minimal energy devotion into the development of the gonad.<ref name=":3"/> Growth is slow, as nutrients are not abundant at depths frequented by the animals. The vastness of their habitat and its sparse population make reproductive encounters a fortuitous event. With [[Semelparity and iteroparity|iteroparity]] often seen in organisms with high adult survival rates, such as the vampire squid, many low-cost reproductive cycles would be expected for the species.{{sfn |Hoving |Laptikhovsky |Robison |2015}}

Reproduction of the vampire squid is unlike any other coleoid cephalopod; the males pass a "packet" of sperm to a female and the female accepts it and stores it in a special pouch inside her mantle. The female may store a male's hydraulically implanted [[spermatophore]] for long periods before she is ready to fertilize her eggs. Once she does, she may need to brood over them for up to 400 days before they hatch. Their reproductive strategy appears to be [[Semelparity and iteroparity|iteroparous]], which is an exception amongst the otherwise semelparous [[Coleoidea]].{{sfn |Hoving |Laptikhovsky |Robison |2015}} During their life, coleoid cephalopods are thought to go through only one reproductive cycle whereas vampire squid have shown evidence of multiple reproductive cycles. After releasing their eggs, new batches of eggs are formed after the female vampire squid returns to resting. This process may repeat up to, and sometimes more than, twenty times in their lifespan. These spawning events happen quite far apart due to the vampire squid's low metabolic rate.<ref name=":3">{{cite journal |last1=Henk-Jan |first1=Hoving |date=20 April 2015 |title=Vampire squid reproductive strategy is unique among coleoid cephalopods |journal= Current Biology |volume=25 |issue=8 |pages=R322–R323 |doi=10.1016/j.cub.2015.02.018 |pmid=25898098 |doi-access=free|bibcode=2015CBio...25.R322H }}</ref>

Few specifics are known regarding the [[ontogeny]] of the vampire squid. Hatchlings are about 8&nbsp;mm in length and are well-developed miniatures of the adults, with some differences: they are transparent, their arms lack webbing, their eyes are smaller proportionally, and their velar filaments are not fully formed.<ref name=":1">{{Cite journal |url=http://biostor.org/reference/74296 |title=Morphological Observations On A Hatchling And A Paralarva Of The Vampire Squid, Vampyroteuthis Infernalis Chun (Mollusca : Cephalopoda) |last=Young |first=R. E. |year=1998 |journal=Proceedings of the Biological Society of Washington |volume=112 |pages=661–666 |via=biostor.org |access-date=2020-02-09}}</ref> Their development progresses through three morphologic forms: the very young animals have a single pair of fins, an [[Paralarva|intermediate form]] has two pairs, and the mature form again has one pair of fins. At their earliest and intermediate phases of development, a pair of fins is located near the eyes; as the animal develops, this pair gradually disappears as the other pair develops.{{sfn|Pickford|1949}} As the animals grow and their surface area to volume ratio drops, the fins are resized and repositioned to maximize gait efficiency. Whereas the young propel themselves primarily by [[jet propulsion#Jet-propelled animals|jet propulsion]], mature adults prefer the more efficient means of flapping their fins.{{sfn|Seibel|Thuesen|Childress|1998}} This unique ontogeny caused confusion in the past, with the varying forms identified as several species in distinct families.{{sfn|Young|2002}}

The hatchlings survive on a generous internal [[yolk]] supply for an unknown period before they begin to actively feed.<ref name=":1"/> The younger animals frequent much deeper waters, feeding on marine snow and [[zooplankton]].<ref name="Golikov 2019 19099"/>