Editing Leopard seal (section)

==Behavior==
[[File:Activity-Time-Budget-during-Foraging-Trips-of-Emperor-Penguins-pone.0050357.s002.ogv|thumb|left|200px|Swimming leopard seal]]
Using data received from [[transmitter]]s called satellite-linked depth recorders (SLDRs) and time-depth recorders (TDRs), which are attached to the seals' heads by scientists, it was determined that leopard seals are primarily shallow divers, but capable of diving deeper than {{Convert|80|m|abbr=out}} in search for food.<ref name=":3">{{Cite journal|last1=Krause|first1=Douglas J.|last2=Goebel|first2=Michael E.|last3=Marshall|first3=Greg J.|last4=Abernathy|first4=Kyler|date=2016-02-24|title=Summer diving and haul-out behavior of leopard seals (Hydrurga leptonyx) near mesopredator breeding colonies at Livingston Island, Antarctic Peninsula|journal=Marine Mammal Science|volume=32|issue=3|pages=839–867|doi=10.1111/mms.12309|issn=0824-0469|doi-access=free|bibcode=2016MMamS..32..839K }}</ref> They are able to complete these dives by collapsing their lungs and re-inflating them at the surface. This is possible by increasing the amount of [[Pulmonary surfactant|surfactant]]s which coats the [[Alveolus|alveoli]] in the lungs for re-inflation. They also have a reinforced [[trachea]] to prevent collapse at great depth pressures.<ref>{{Cite web|url=http://cetus.ucsd.edu/sio133/PDF/BertaChap10.pdf|title=Respiration and Diving Physiology|website=Cetus UCSD}}</ref>

These seals feeds on a wide variety of creatures; young leopard seals usually eat mostly [[krill]], squid and [[fish]]. Adults are able to take on more difficult but substantial prey, famously including [[Emperor penguin|emperor]], [[King penguin|king]], [[Rockhopper penguin|rockhopper]], [[Adélie penguin|Adélie]], [[Gentoo penguin|gentoo]], and [[chinstrap penguin]]s, though they also prey on other seal species such as [[Weddell seal|Weddell]], [[crabeater seal|crabeater]], [[Ross seal|Ross]], young [[southern elephant seal]]s, and [[fur seal]] pups.<ref>{{cite web|title = POV: Why Are Leopard Seals Eating Fur Seal Pups?|url = http://video.nationalgeographic.com/video/news/150807-leopard-seal-fur-seal-hunt-vin|archive-url = https://web.archive.org/web/20150810002324/http://video.nationalgeographic.com/video/news/150807-leopard-seal-fur-seal-hunt-vin|url-status = dead|archive-date = August 10, 2015|website = video.nationalgeographic.com|access-date = 2015-08-08}}</ref>
{{Multiple image
| image1            = Fish8426 - Flickr - NOAA Photo Library.jpg
| caption1          = Attacking an [[emperor penguin]]
| image2            = Fish8874 (28002875125).jpg
| caption2          = Leopard seal with a male [[Antarctic fur seal]] (right) on the shores of [[Livingston Island]]. Juvenile fur seals may be preyed upon by leopard seals
| align             = 
| direction         = vertical
}}
Research shows that on average, the [[Aerobic metabolism|aerobic]] dive limit for juvenile seals is around 7 minutes, which means that during the winter months juvenile leopard seals do not eat krill, which is a major part of older seals' diets, since krill is found deeper during this time.<ref>{{cite journal | last1 = Kuhn | first1 = Carey E. | last2 = McDonald | first2 = Birgitte I. | last3 = Shaffer | first3 = Scott A. | last4 = Barnes | first4 = Julie | last5 = Crocker | first5 = Daniel E. | last6 = Burns | first6 = Jennifer | last7 = Costa | first7 = Daniel P. | year = 2005 | title = Diving physiology and winter foraging behavior of a juvenile leopard seal (Hydrurga leptonyx) | journal = Polar Biology | volume = 29 | issue = 4| pages = 303–307 | doi = 10.1007/s00300-005-0053-x | s2cid = 32195795 }}</ref> This might occasionally lead to co-operative hunting. Co-operative hunting of leopard seals on Antarctic fur seal pups has been witnessed, which could be a mother helping her older pup, or could also be female-male couple interactions, to increase their hunting productivity.<ref>{{cite journal | last1 = Hiruki | first1 = Lisa M. | last2 = Schwartz | first2 = Michael K. | last3 = Boveng | first3 = Peter L. | year = 1999 | title = Hunting and social behaviour of leopard seals (Hydrurga leptonyx) at Seal Island, South Shetland Islands, Antarctica | url = https://digitalcommons.unl.edu/usdeptcommercepub/151| journal = Journal of Zoology | volume = 249 | issue = 1| pages = 97–109 | doi = 10.1111/j.1469-7998.1999.tb01063.x | url-access = subscription }}</ref>

Around the sub-Antarctic [[South Georgia Island|island of South Georgia]], the [[Antarctic fur seal]] (''Arctocephalus gazella'') is the main prey. [[Antarctic krill]] (''Euphasia superba''), [[southern elephant seal]] pups and [[petrel]]s such as the [[Pelecanoides|diving petrel]] (''Pelecanoides'') and the [[Daption|cape petrel]] (''Daption'') have also been taken as prey.<ref>{{cite journal|author=Walker, T.R.|author2=Boyd, I.L.|author3=Mccafferty, D.J.|author4=Huin, N.|author5=Taylor, R.I.|author6=Reid, K. |year=1998|title= Seasonal occurrence and diet of leopard seals (''Hydrurga leptonyx'') at Bird Island, South Georgia|journal= Antarctic Science|volume= 10|issue=1|pages= 75–81|doi=10.1017/S0954102098000108|url=https://www.researchgate.net/publication/231850677|bibcode=1998AntSc..10...75W|s2cid=85575118}}</ref> Vagrant leopard seals in [[New Zealand]] have been observed preying on [[chondrichthyan]]s; elephantfish (''[[Callorhinchus milii]]''), [[Hydrolagus|ghost sharks]], and [[spiny dogfish]] were recorded as prey items. Additionally, this population of leopard seals and those in [[Australia]] were noted to bear wounds from [[chimaeriform]]s and [[stingray]]s respectively.<ref>{{Cite journal|title=Leopard Seals (Hydrurga leptonyx) in New Zealand waters predating on chondrichthyans|year=2021|doi=10.3389/fmars.2021.795358|doi-access=free|last1=Van Der Linde|first1=Krista|last2=Visser|first2=Ingrid N.|last3=Bout|first3=Rick|last4=Lalas|first4=Chris|last5=Shepherd|first5=Lara|last6=Hocking|first6=David|last7=Finucci|first7=Brittany|last8=Fyfe|first8=Jim|last9=Pinkerton|first9=Matthew|journal=Frontiers in Marine Science|volume=8|bibcode=2021FrMaS...895358V }}</ref>

When hunting penguins, the leopard seal patrols the waters near the edges of the ice, almost completely submerged while waiting for the birds to enter the ocean. It kills the swimming bird by grabbing the feet, then shaking the penguin vigorously and beating its body against the surface of the water repeatedly until the penguin is dead. Previous reports stating that the leopard seal [[Skinning|skins]] its prey before feeding have been found to be incorrect. Lacking the teeth necessary to slice its prey into manageable pieces, it flails its prey from side to side tearing and ripping it into smaller pieces.{{Citation needed|date=May 2025}}

Krill is eaten by [[suction feeding|suction]], and [[wikt:strained|strained]] through the seal's teeth, allowing leopard seals to switch to different feeding styles. Such generalization and adaptations may be responsible for the seal's success in the challenging Antarctic ecosystem.<ref>{{Cite journal | url=https://www.nature.com/news/leopard-seals-suck-up-krill-like-whales-1.11672 | doi=10.1038/nature.2012.11672| title=Leopard seals suck up krill like whales| journal=Nature| year=2012| last1=Yong| first1=Ed| s2cid=87484971| doi-access=free}}</ref>

The only natural predator of leopard seals is the [[orca]].<ref name=Aus>{{cite web|title=Leopard seals|url=http://www.antarctica.gov.au/about-antarctica/wildlife/animals/seals-and-sea-lions/leopard-seals|publisher=Australian Antarctic Division|access-date=14 August 2017|language=en-au}}</ref> 

===Acoustic behavior===
{{Further|Animal communication|Mating call}}
Leopard seals are very vocal underwater during the austral summer.<ref name="Rogers TL, Ciaglia MB, Klinck H, Southwell C 2013 e52542"/> The male seals produce loud calls (153 to 177 dB 1 μPa at 1 m) for many hours each day.<ref>{{cite journal|author= Rogers TL |year=2014|title= Source levels of the underwater calls of a male leopard seal |journal= The Journal of the Acoustical Society of America|volume=136|issue=4|pages= 1495–1498|doi=10.1121/1.4895685|pmid=25324053|bibcode=2014ASAJ..136.1495R}}</ref> While singing the seal hangs upside down and rocks from side to side under the water. Their back is bent, the neck and cranial thoracic region (the chest) is inflated and as they call their chest pulses. The male calls can be split into two categories: vocalizing and silencing; vocalizing is when they are making noises underwater, and silencing noted{{clarify|date=February 2024}} as the breathing period at the air surface.<ref name=":2">{{Cite journal|last1=Rogers|first1=Tracey L.|last2=Cato|first2=Douglas H.|date=2002|title=Individual Variation in the Acoustic Behaviour of the Adult Male Leopard Seal, Hydrurga leptonyx|jstor=4535987|journal=Behaviour|volume=139|issue=10|pages=1267–1286|doi=10.1163/156853902321104154}}</ref> Adult male leopard seals have only a few stylized calls, some are like bird or [[Cricket (insect)|cricket]]-like [[wikt:trill|trill]]s yet others are low haunting [[wikt:moan|moan]]s.<ref name="Rogers, T. L., Cato, D. H., & Bryden, M. M. 1996 414–427">{{cite journal|author= Rogers, T. L.|author2= Cato, D. H.|author3= Bryden, M. M.|name-list-style= amp |year=1996|title= Behavioral significance of underwater vocalizations of captive leopard seals, Hydrurga leptonyx.|journal= Marine Mammal Science|volume=12|issue=3|pages=414–427|doi=10.1111/j.1748-7692.1996.tb00593.x|bibcode= 1996MMamS..12..414R}}</ref> Scientists have identified five distinctive sounds that male leopard seals make, which include: the high double trill, medium single trill, low descending trill, low double trill, and a hoot with a single low trill. These cadences of calls are believed to be a part of a long range acoustic display for territorial purposes, or to attract a potential mate.<ref name=":2" />

The leopard seals have age-related differences in their calling patterns, just like birds. The younger male seals have many different types of variable calls, but the mature male seals have only a few, highly stylized calls.<ref>{{cite journal|author= Rogers, T. L|year=2007|title= Age-related differences in the acoustic characteristics of male leopard seals, Hydrurga leptonyx|journal= The Journal of the Acoustical Society of America|volume=122|issue=1|pages=596–605|doi=10.1121/1.2736976|pmid=17614516|bibcode=2007ASAJ..122..596R}}</ref> Each male leopard seal produces these individual calls, and can arrange their few call types into individually distinctive sequences (or songs).<ref>{{cite journal|author1=Rogers, Tracey L. |author2=Cato, Douglas H. |year=2002|title=Individual Variation in the Acoustic Behaviour of the Adult Male Leopard Seal, ''Hydrurga leptonyx''|journal=Behaviour|volume=139|issue=10|pages=1267–1286|jstor=4535987|doi=10.1163/156853902321104154}}</ref> The acoustic behavior of the leopard seal is believed to be linked to their breeding behaviour. In male seals, vocalizing coincides with the timing of their [[breeding season]], which falls between November and the first week of January; captive female seals vocalize when they have elevated [[reproductive hormone]]s.<ref name="Rogers, T. L., Cato, D. H., & Bryden, M. M. 1996 414–427"/> Conversely, a female leopard seal can attribute{{clarify|date=February 2024}} calls to their environment as well; however, usually it is to gain the attention of a pup, after getting back from a forage for food.

===Breeding habits===
[[File:Leopard Seal and pup by Jeff Lipshitz (49848008693).jpg|left|thumb|A mother leopard seal with her pup.]]
Vocalization is thought to be important in breeding, since males are much more vocal around this time. Mating takes place in the water, and then the male leaves the female to care for the pup, which the female gives birth to after an average gestation period of 274 days.<ref name="ReferenceA"/> Most leopard seal breeding take place on a pack of ice.<ref name="ReferenceB">{{cite journal | last1 = Southwell | first1 = Colin | last2 = Kerry | first2 = Knowles | last3 = Ensor | first3 = Paul | last4 = Woehler | first4 = Eric J. | last5 = Rogers | first5 = Tracey | year = 2003 | title = The timing of pupping by pack-ice seals in East Antarctica | journal = Polar Biology | volume = 26 | issue = 10| pages = 648–652 | doi = 10.1007/s00300-003-0534-8 | bibcode = 2003PoBio..26..648S | s2cid = 7565646 }}</ref>

Since leopard seals live in an area difficult for humans to survive in, not much is known on their reproduction and breeding habits. However, it is known that their breeding system is [[Polygyny in animals|polygynous]], meaning that males mate with multiple females during the mating period. Females reach [[sexual maturity]] between the ages of three and seven, and can give birth to a single pup during the summer on the floating ice floes of the Antarctic pack ice; males reach sexual maturity around the age of six or seven years.<ref name="Marine Bio" /> Mating occurs from December to January, shortly after the pups are weaned when the female seal is in [[Estrous cycle|estrus]].<ref name="ReferenceA">"Reproduction - Encyclopedia of Life". Encyclopedia of Life. Retrieved 2018-05-15.</ref> In preparation for the pups, the females dig a circular hole in the ice as a home for the pup. A newborn pup weighs around {{cvt|30|kg}} and are usually with their mother for a month, before they are [[weaned]] off. The male leopard seal does not participate in childcare, and returns to its solitary lifestyle after the breeding season.<ref name=":1" /> Leopard seal pup mortality within the first year is close to 25%.<ref name="Administrator">{{Cite web|url=https://www.pinnipeds.org/seal-information/species-information-pages/the-phocid-seals/leopard-seal|title=Leopard Seal|last=Administrator|website=www.pinnipeds.org|language=en-gb|access-date=2018-06-04}}</ref>

Five research voyages were made to Antarctica in 1985, 1987 and 1997–1999 to survey leopard seals.<ref name="ReferenceB"/> They sighted seal pups from the beginning of November to the end of December, and noticed that there was about one pup for every three adults, and they also noticed that most of the adults were staying away from other adults during this season, and when they were seen in groups they showed no sign of interaction.<ref>{{cite journal | last1 = Borsa | first1 = Philippe | year = 1990 | title = Seasonal occurrence of the leopard seal, Hydrurga leptonyx, in the Kerguelen Islands | journal = Canadian Journal of Zoology | volume = 68 | issue = 2| pages = 405–408 | doi = 10.1139/z90-059 | bibcode = 1990CaJZ...68..405B }}</ref>