leopard seal

Henri Marie Ducrotay de Blainville, a French zoologist, described the leopard seal in 1820 from a stuffed specimen from the collection of one M. Hauville, in Le Havre. The skin that produced this work of taxidermy was sourced from "the southern seas",{{Efn|des mer du sud}} that he ascertained to be from around the Falkland Islands.{{Efn|des environs des îles Falckland ou Malouines.}} Blainville describes the specimen as "beautiful", 7-8 "pieds" long ({{Convert|7|-|8|ft|abbr=in}} long) and elongated, the form and features of the head resembling the "phoque moine" or monk seal, with a small number of whiskers short and simple in shape. Blainville was not able to find the ear opening. The "anterior" limbs are falciform, consisting of five fingers which decrease in size from the first to the fifth, tipped with very small claws, with that of the thumb not being "terminal".{{Efn|...et cinq ongles assez petits, quoique bien évidens; celui du pouce n'est pas terminal}} The hindlimbs are very distal (far back{{efn|très-reculés}}) and close to the short tail; these also consist of five digits, though in contrast to the forelimb, the middle toe is the shortest, with the rear flippers forming a "swallowtail".{{efn|dont les extrêmes sont les plus longs}} The skin he examined was described as yellow-white with a brownish dorsum; this is evidently a result of the skin discoloring, as taxidermies degrade over time. He thought that this new species, Phoca leptonyx,{{efn|lepto- + onyx; "thin-clawed"}} must correspond to the animal that "navigators of austral seas" named the "sea calf".

Blainville found it comparable to a specimen he refers to as the "third skull" he examined and described in the same work, possessing the same number and shape of the incisors.{{efn|le nombre et la forme des incisives sont en effet absolument le mêmes}} This skull, unlabeled and thus of unknown locality, was noted as fresher and more bleached than the second skull he examined, being 10-12 pouces long. At first glance, he found that the skull had significant resemblance to the skull of the "phoque commun" or common seal, moreso than the previous two; though this skull was of bigger dimensions, was not as flattened nor narrowed post-orbitally,{{efn|...par moins d'aplatissement du crâne proprement dit, un moindre rétrécissement post-orbitaire}} and notably had a well developed sagittal crest and enlarged nasal fossae.{{efn|This passage was followed by;...ce qu'indique une énorme épaisseur inter-orbitaire, er par celle de leurs ouvertures antérieure et postérieure.{{Clarify|reason=I have no idea how to translate this and how relevant it is to the prior passage|date=May 2025}}}} The robust molars of this skull possesses two roots and three cusps, pointed and prominent with the central cusp being the tallest. Five molars were present on each side of the jawbone, after the robust canines,{{efn|les canines ne diffèrent guère aussi de celles du veau marin que par beaucoup plus de force}} and the two incisors, the outer pair of incisors resembling the shape of the canines.{{cite journal |author=Henri Marie Ducrotay de Blainville |title=Sur Quelques Cranes de Phoques |journal=Journal de Physique, de Chimie, d'Histoire Naturelle et des Arts |date=July 1820 |volume=91 |location=Paris |url=https://www.biodiversitylibrary.org/page/6174274#page/321/mode/1up |access-date=23 May 2025}}{{rp|288-289}}

The genus Hydrurga{{efn|hydro + ergon; "water worker"{{Verify quote|date=May 2025}}}} was erected by Johannes von Nepomuk Franz Xaver Gistel in 1848.{{cite book |last1=Gistel |first1=Johannes |title=Naturgeschichte des Thierreichs : für höhere Schulen |page=XI |date=1851 |others=first published 1848 |publisher=Scheitlin & Krais |location=Stuttgart |url=https://www.biodiversitylibrary.org/item/175526#page/15/mode/1up|doi=10.5962/bhl.title.97235 |access-date=23 May 2025}}

File:Leopard Seal skull 1844.jpg

The leopard seal has a distinctively long and muscular body shape when compared to other seals. The overall length of adults is {{convert|2.4|–|3.5|m|ft|abbr=on}} and their weight is in the range {{convert|200|to|600|kg}}, making them the same length as the northern walrus but usually less than half the weight.{{cite book |author=Nowak, Ronald M |title=Walker's Marine Mammals of the World |publisher=Johns Hopkins University Press: Baltimore, MD |year=2003}}{{Cite web|url=https://www.marinebio.org/species/leopard-seals/hydrurga-leptonyx/|title=Leopard Seals, Hydrurga leptonyx|website=Marine Bio}} They are covered in a thick layer of blubber that helps to keep them warm while in the cold temperatures of the Antarctic. This blubber also helps to streamline their body making them more hydrodynamic, and thus able to hunt down swift prey. A seal's body condition can be ascertained through blubber thickness, along with general girth, weight, and length measurements.{{Cite journal|last1=Krause|first1=Douglas J.|last2=Hinke|first2=Jefferson T.|last3=Perryman|first3=Wayne L.|last4=Goebel|first4=Michael E.|last5=LeRoi|first5=Donald J.|date=2017-11-29|title=An accurate and adaptable photogrammetric approach for estimating the mass and body condition of pinnipeds using an unmanned aerial system | journal = PLOS ONE|volume=12|issue=11|pages=e0187465|doi=10.1371/journal.pone.0187465 | pmc = 5706667|pmid=29186134|bibcode=2017PLoSO..1287465K|doi-access=free}}

Females are larger than males by up to 50%; the leopard seal is sexually dimorphic.{{cite journal |last=Kienle |first=Sarah S. |date=17 August 2022 |title=Plasticity in the morphometrics and movements of an Antarctic apex predator, the leopard seal |journal= Frontiers in Marine Science|volume=9 |doi=10.3389/fmars.2022.976019 |doi-access=free |bibcode=2022FrMaS...976019K }}

It is perhaps best known for its massive jaws, which allow it to be one of the top predators in its environment. The seal's canine teeth are up to {{convert|2.5|cm|0|abbr=on}} long.{{cite book|last=Kindersley |first=Dorling |year=2005 |orig-year=2001 |title=Animal |location=New York City |publisher=DK Publishing |isbn=978-0-7894-7764-4}} These and the incisor teeth are sharp like those of other carnivores, but their molars lock together in a way that allows them to "sieve" krill from the water. This characteristic is shared with the other species in the tribe Lobodontini such as the crabeater seal, and is the trait that gives the tribe its name.

File:Hydrurga leptonyx.png

As "true" seals of the family Phocidae, they do not have external ears or pinnae, but possess an internal ear canal that leads to an external opening.{{Cite web|url=https://travelwild.com/resources/antarctica-wildlife/leopard-seal/|title=Leopard seal {{!}} TravelWild Expeditions|website=TravelWild Expeditions|access-date=2018-04-18}} Their hearing in air is similar to that of a human, but scientists have noted that leopard seals use their ears in conjunction with their whiskers to track prey under water. The whiskers are short and clear.

Their front flippers are extremely large in comparison to other phocids. Their large front flippers are used to steer themselves through the water column making them extremely agile while hunting. They use their front flippers similarly to sea lions (family Otariidae){{Cite web|url=https://www.afsc.noaa.gov/nmml/education/pinnipeds/leopard.php|title=Leopard Seals|website=NOAA Fisheries National Oceanic and Atmospheric Administration Alaska Fisheries Science Center|date=27 January 2021}}

The pelage is counter-shaded; consisting mainly of a blend of silver and dark gray, with a distinctive spotted leopard-like pattern on the dorsum, and a white to light gray color ventrally.{{Cite web|url=http://species-identification.org/species.php?species_group=marine_mammals&id=52|title=Marine Species Identification Portal : Leopard seal - Hydrurga leptonyx|website=species-identification.org|access-date=2018-03-19}}

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Leopard seals are pagophilic ("ice-loving") seals, which primarily inhabit the Antarctic pack ice between 50˚S and 80˚S. Higher densities of leopard seals are seen in West Antarctica than in other regions.{{cite journal|author=Southwell, C.|author2=Bengtson, J.|author3=Bester, M.|author4=Schytte Blix, A.|author5=Bornemann, H.|author6=Boveng, P.|author7=Cameron, M.|author8=Forcada, J.|author9=Laake, J.|year=2012|title=A review of data on abundance, trends in abundance, habitat use and diet of ice-breeding seals in the Southern Ocean.|journal=CCAMLR Science|volume=19|pages=1–26|author10=Nordøy, E.|author11=Plötz, J.|author12=Rogers, T.|author13=Southwell, D.|author14=Steinhage, D.|author15=Stewart, B.S.|author16=Trathan, P}}{{cite journal|author=Forcada, J.|author2=Trathan, P.|author3=Boveng, Boyd|author4=I., Burns|author5=J., Costa|author6=D., Fedak|author7=M., Rogers|author8=T., Southwell, C.|year=2012|title=Responses of Antarctic pack-ice seals to environmental change and increasing krill fishing.|journal=Biological Conservation|volume=149|issue=1|pages=40–50|doi=10.1016/j.biocon.2012.02.002|bibcode=2012BCons.149...40F |s2cid=7892053 |url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1337&context=usdeptcommercepub|url-access=subscription}}

Most leopard seals remain within the pack ice throughout the year and remain solitary during most of their lives with the exception of a mother and her newborn pup.{{cite journal|author= Rogers, T.L.|author2= Hogg, C.|author3= Irvine, A.|name-list-style= amp |year=2005|title= Spatial movement of adult leopard seals (Hydrurga leptonyx) in Prydz Bay, Eastern Antarctica. |journal= Polar Biology |volume=28|issue=6|pages= 456–463|doi=10.1007/s00300-004-0703-4|bibcode= 2005PoBio..28..456R|s2cid= 22535400}}{{cite journal|author= Meade, J.|author2= Ciaglia, M.B.|author3= Slip, D.J.|author4= Negrete, J.|author5= Márquez M.E.I., Rogers, T. |year=2015|title= Spatial patterns in activity of leopard seals Hydrurga leptonyx in relation to sea ice.|journal= Marine Ecology Progress Series |volume=521|pages= 265–275|doi=10.3354/meps11120|bibcode=2015MEPS..521..265M|s2cid= 87706193|doi-access= free}} These matrilineal groups can move further north in the austral winter to sub-antarctic islands and the coastlines of the southern continents to provide care for their pups. While solitary animals may appear in areas of lower latitudes, females rarely breed there. Some researchers believe this is due to safety concerns for the pups.{{cite news |last1=Taylor |first1=Margot |title=Odds against St Kilda leopard seal pup |url=https://www.odt.co.nz/news/dunedin/odds-against-st-kilda-leopard-seal-pup |access-date=2020-07-25 |work=Otago Daily Times |date=2017-09-27}}

The estimated population of this species ranges from 220,000 to 440,000 individuals, putting leopard seals at "Least Concern". Although there is an abundance of leopard seals in the Antarctic, they are difficult to survey by traditional audiovisual techniques{{Contradictory inline|date=May 2025}} as they spend long periods of time vocalizing under the water’s surface during the austral spring and summer, when audiovisual surveys are carried out.{{cite journal|author= Southwell, C.|author2= Paxton, C.|author3= Borchers, D.|author4= Boveng, P. Rogers, T.|author5= de la Mare, W.|name-list-style= amp|year=2008|title= Uncommon or cryptic? Challenges in estimating leopard seal abundance by conventional but state-of-the-art methods |journal= Deep-Sea Research Part I: Oceanographic Research Papers |volume=55|issue=4|pages= 519–531|doi=10.1016/j.dsr.2008.01.005|bibcode= 2008DSRI...55..519S}} This habit of submarine vocalizing makes leopard seals naturally suited for acoustic surveys, as are conducted with cetaceans, allowing researchers to gather most of what is known about them.{{cite journal|vauthors=Rogers TL, Ciaglia MB, Klinck H, Southwell C |year=2013|title= Density Can Be Misleading for Low-Density Species: Benefits of Passive Acoustic Monitoring|journal= PLOS ONE |volume=8|issue=1|pages= e52542|doi=10.1371/journal.pone.0052542|pmid=23326339|pmc=3541380|bibcode=2013PLoSO...852542R|doi-access=free}}

Sightings of vagrant leopard seals have been recorded on the coasts of Geraldton, Western Australia, multiple locales in New Zealand,{{efn|Where individuals have even been seen on the foreshores of major cities such as Auckland,{{Cite web|url=https://www.doc.govt.nz/nature/native-animals/marine-mammals/seals/leopard-seal/|title=Leopard seal|website=Department of Conservation|language=en-nz|access-date=2020-02-24}} Dunedin{{Cite web|url=https://www.odt.co.nz/regions/north-otago/leopard-seal-sightings-new-zealand-rise|title=Leopard seal sightings in New Zealand on the rise|last=MacLean|first=Hamish|date=2019-01-19|website=Otago Daily Times |language=en|access-date=2020-02-24}} and Wellington{{Cite web|url=https://www.nzherald.co.nz/nz/antarctic-leopard-seal-turns-up-on-wellingtons-lyall-bay-beach/EZ6YTOJO644N5LF5NZNTXUMCRE/|title=Antarctic Leopard seal turns up on Wellington's Lyall bay beach|date=10 August 2021 }}}} South America, and South Africa. Fossil evidence suggests that leopard seals were present in South Africa during the Late Pleistocene.{{cite journal|author1=Avery, G.|author2=Klein, R.G.|year=2011|title=Review of fossil phocid and otariid seals from the southern and western coasts of South Africa|journal=Transactions of the Royal Society of South Africa|volume=66|issue=1|pages=14–24|doi=10.1080/0035919X.2011.564490|bibcode=2011TRSSA..66...14A }}{{cite journal|author1=Oster, S.|author2=Reynard, J.P.|author3=Cawthra, H.C.|author4=Esteban, I.|author5=Pargeter, J.|author6=Fisher, E.C.|year=2024|title=Late Pleistocene and Holocene fauna from Waterfall Bluff Rock Shelter, Mpondoland, South Africa|journal=South African Journal of Science|volume=120|issue=11/12|doi=10.17159/sajs.2024/17449|doi-access=free}}

File:Activity-Time-Budget-during-Foraging-Trips-of-Emperor-Penguins-pone.0050357.s002.ogv

Using data received from transmitters 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.{{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 }} 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 surfactants which coats the alveoli in the lungs for re-inflation. They also have a reinforced trachea to prevent collapse at great depth pressures.{{Cite web|url=http://cetus.ucsd.edu/sio133/PDF/BertaChap10.pdf|title=Respiration and Diving Physiology|website=Cetus UCSD}}

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, king, rockhopper, Adélie, gentoo, and chinstrap penguins, though they also prey on other seal species such as Weddell, crabeater, Ross, young southern elephant seals, and fur seal pups.{{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}}

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Research shows that on average, the 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.{{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 }} 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.{{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 }}

Around the sub-Antarctic island of South Georgia, the Antarctic fur seal (Arctocephalus gazella) is the main prey. Antarctic krill (Euphasia superba), southern elephant seal pups and petrels such as the diving petrel (Pelecanoides) and the cape petrel (Daption) have also been taken as prey.{{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}} Vagrant leopard seals in New Zealand have been observed preying on chondrichthyans; elephantfish (Callorhinchus milii), 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 chimaeriforms and stingrays respectively.{{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 }}

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 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, and 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.{{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}}

The only natural predator of leopard seals is the orca.{{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}}

{{Further|Animal communication|Mating call}}

Leopard seals are very vocal underwater during the austral summer. The male seals produce loud calls (153 to 177 dB 1 μPa at 1 m) for many hours each day.{{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}} 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.{{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}} Adult male leopard seals have only a few stylized calls, some are like bird or cricket-like trills yet others are low haunting moans.{{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}} 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.

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.{{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}} Each male leopard seal produces these individual calls, and can arrange their few call types into individually distinctive sequences (or songs).{{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}} 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 hormones. 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.

File:Leopard Seal and pup by Jeff Lipshitz (49848008693).jpg

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. Most leopard seal breeding take place on a pack of ice.{{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 }}

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 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. Mating occurs from December to January, shortly after the pups are weaned when the female seal is in estrus."Reproduction - Encyclopedia of Life". Encyclopedia of Life. Retrieved 2018-05-15. 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. Leopard seal pup mortality within the first year is close to 25%.{{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}}

Five research voyages were made to Antarctica in 1985, 1987 and 1997–1999 to survey leopard seals. 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.{{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 }}

Leopard seals are large predators presenting a potential risk to humans. However, attacks on humans are rare. Most human perceptions of leopard seals are shaped by historic encounters between humans and leopard seals that occurred during the early days of Antarctic exploration.{{Cite journal |doi = 10.1017/S0954102006000058|title = Interactions between humans and leopard seals|journal = Antarctic Science|volume = 18|pages = 61–74|year = 2006|last1 = Muir|first1 = Shona F.|last2 = Barnes|first2 = David K.A.|last3 = Reid|first3 = Keith|issue = 1|bibcode = 2006AntSc..18...61M|s2cid = 53648359}} Examples of aggressive behaviour, stalking and attacks are rare, but have been documented. A large leopard seal attacked Thomas Orde-Lees (1877–1958), a member of Sir Ernest Shackleton's Imperial Trans-Antarctic Expedition of 1914–1917, when the expedition was camping on the sea ice. The "sea leopard", about {{convert|12|ft|abbr=on}} long and {{convert|1100|lb|abbr=on}}, chased Orde-Lees on the ice. He was saved only when another member of the expedition, Frank Wild, shot the animal.{{cite book |last=Shackleton |first=Ernest |date=1998 |title=South |location=New York, NY |publisher=The Lyons Press |page=[https://archive.org/details/southlastantarct0000shac/page/112 112] |isbn=1-55821-783-5 |author-link=Ernest Shackleton |url-access=registration |url=https://archive.org/details/southlastantarct0000shac/page/112 }}

In 1985, Canadian-British explorer Gareth Wood was bitten twice on the leg when a leopard seal tried to drag him off the ice and into the sea. His companions managed to save him by repeatedly kicking the animal in the head with the spiked crampons on their boots.Carrington, Damian (2003-07-24). [https://www.newscientist.com/article/dn3978-inquiry-into-fatal-leopard-seal-attack-begins.html Inquiry into fatal leopard seal attack begins]. NewScientist.com. Retrieved on 2013-02-24. On 26 September 2021, near the dive site Spaniard Rock at Simon's Town, South Africa, three spear-fishermen encountered a leopard seal while spearing approximately 400 m offshore. The seal attacked them and, while they were swimming back to shore, disarmed them of their flippers and spearguns and kept harassing the men over the course of half an hour, inflicting multiple bite and puncture wounds.{{cite web|url=https://www.nsri.org.za/2021/09/nsri-appeal-to-the-public-to-be-cautious-around-seals-and-sea-animals-in-general/|title=NSRI appeal to the public to be cautious around seals and sea animals in general|website=National Sea Rescue Institute|access-date=1 October 2021}} Leopard seals have shown a predilection for attacking the black, torpedo-shaped pontoons of rigid inflatable boats, leading researchers to equip their craft with special protective guards to prevent them from being punctured.{{Cite book|title = The Encyclopedia of World Wildlife|last1 = Briggs|first1 = Mike|publisher = Parragon|year = 2005|isbn = 978-1-40545-680-7|page = 60|first2 = Peggy|last2 = Briggs}}

On the other hand, National Geographic magazine photographer Paul Nicklen captured pictures of a female leopard seal bringing live, injured, and then dead penguins to him, possibly in an attempt to "nurture" the photographer; the seal apparently continued to provide penguins for Nicklen for four days.[http://www.dpreview.com/news/2012/10/18/National-Geographic-Photographer-Paul-Nicklen-surprise-encounter-with-Leopard-Seal-Antarctica National Geographic photographer's surprise encounter with deadly predator]. dpreview.com (2012-10-18){{Cite web |date=March 11, 2014 |title=How a Leopard Seal Fed Me Penguins |url=https://www.nationalgeographic.com/adventure/article/140311-paul-nicklen-leopard-seal-photographer-viral |archive-url=https://web.archive.org/web/20210228073531/https://www.nationalgeographic.com/adventure/article/140311-paul-nicklen-leopard-seal-photographer-viral |url-status=dead |archive-date=February 28, 2021 |access-date=April 23, 2023 |website=National Geographic |language=en}}

{{Main|Taronga Zoo#World's only leopard seals in a zoo}}

File:Sealion in training (3616810581).jpg]]

The Taronga Zoo kept rescued leopard seals from 1999 to 2014. These seals were thought to be vagrants; washing up on Australian beaches emaciated and bearing bites from cookiecutter sharks. After being nursed back to health, they were not released back into the wild as it was feared that they would transmit diseases to the wild population of leopard seals, so they remained in the care of the zoo until their deaths. In order from date of rescue, they were named Brooke, Sabine, and Casey.{{Cite web |title=A Whisker into Leopard Seal Life |url=http://taronga.org.au/news/2018-07-11/whisker-leopard-seal-life |access-date=2023-03-05 |website=A Whisker into Leopard Seal Life {{!}} Taronga Conservation Society Australia |language=en}}

{{Main|Owha}}

File:Owha the Leopard Seal (cropped).jpg 2016]]

Owha (full name: {{Lang|mi|He owha nā ōku tūpuna|italic=yes}}) is a female leopard seal that remained around the coastline of the North Island from 2012 to at least May 2022, recognized by scars on her cheek and flank. She is claimed to be the longest tracked leopard seal in the world.{{Cite web |title=Leopard seal provoked |url=https://www.doc.govt.nz/news/media-releases/2019/leopard-seal-provoked/ |access-date=11 June 2024 |website=Department of Conservation |language=en-nz}}{{Cite web |title=Owha and her friends awarded citizenship |url=https://niwa.co.nz/news/owha-and-her-friends-awarded-citizenship |access-date=11 June 2024 |website=NIWA}}{{Cite news |date=15 August 2019 |title=Oh no Owha! Seal makes snack of Auckland dinghies |url=https://www.rnz.co.nz/news/national/396734/oh-no-owha-seal-makes-snack-of-auckland-dinghies |access-date=11 June 2024 |work=RNZ |language=en-nz}}{{Cite news |date=14 October 2016 |title=Antarctic leopard seal given a name as it makes Auckland her new home |url=https://www.stuff.co.nz/national/85369451/antarctic-leopard-seal-given-a-name-as-it-makes-auckland-her-new-home?rm=m |access-date=11 June 2024 |work=Stuff}}{{Cite web |date=28 June 2022 |title=Have you seen Owha? |url=https://www.facebook.com/LeopardsealsightingsNZ/posts/1737416676600872/ |access-date=31 July 2024 |website=Facebook |vauthors=((Leopard Seals NZ))}}

In 2003, biologist Kirsty Brown of the British Antarctic Survey was killed by a leopard seal while conducting research snorkeling in Antarctica. This was the first recorded human fatality attributed to a leopard seal.{{cite web|title=Leopard Seal Kills Scientist in Antarctica|url=http://news.nationalgeographic.com/news/2003/08/0806_030806_sealkiller.html|archive-url=https://web.archive.org/web/20030808010225/http://news.nationalgeographic.com/news/2003/08/0806_030806_sealkiller.html|url-status=dead|archive-date=August 8, 2003|work=National Geographic Society|date=August 6, 2003|first=James|last=Owen|access-date=2007-12-10}} Brown was part of a team of four researchers taking part in an underwater survey at South Cove, near the U.K.'s Rothera Research Station. Brown and another researcher, Richard Burt, were snorkeling in the water. Burt was snorkeling at a distance of 15 metres (nearly 50 feet) from Brown when the team heard a scream and saw Brown disappear deeper into the water. She was rescued by her team, but they were unable to resuscitate her. It was later revealed that the seal had held Brown underwater for around six minutes at a depth of up to {{convert|70|meters|ft}}, drowning her. Furthermore, she suffered a total of 45 separate injuries (bites and scratches), most of which were concentrated around her head and neck.{{fact|date=December 2024}}

In a report read at the inquiry into Brown's death, Professor Ian Boyd from the University of St Andrews stated that the seal may have mistaken her for a fur seal, or been frightened by her presence and attacked in defence; Professor Boyd said that leopard seal attacks on humans were extremely rare, but warned that they may potentially become more common due to increased human presence in Antarctica. The coroner recorded the cause of death as “accidental” and “caused by drowning due to a leopard seal attack”.Gyford, Sue (2003-11-14). [http://www.ecophotoexplorers.com/files/pdf/KirstyBrownInquest.pdf] {{Webarchive|url=https://web.archive.org/web/20160418201732/http://www.ecophotoexplorers.com/files/pdf/KirstyBrownInquest.pdf|date=2016-04-18}}. ecophotoexplorers.com. Retrieved on 2019-08-20

{{Expand section|This section does not actually talk about the issues, logistics, and actions taken to conserve the species|date=May 2025}}

The only known predators of the leopard seals are orcas and sharks.{{Citation needed|date=May 2025|reason=What sharks? Are there records of southern sleeper sharks taking Hydrurga?}} Because they are limited to a subpolar distribution in the Antarctic, they may be at risk as polar ice caps diminish with global warming. In the wild, leopard seals can live up to 26 years old.{{Cite web|url=https://www.seals-world.com/leopard-seal/|title=Leopard Seal - Seal Facts and Information|website=www.seals-world.com|date=27 January 2014 |language=en-US|access-date=2018-04-18}} Leopard seal hunting is regulated by the Antarctic Treaty and the Convention for the Conservation of Antarctic Seals (CCAS).

{{Notelist}}

{{Reflist|30em}}

• {{cite book|editor1=Perrin, W. F. |editor2=Würsig, B. |editor3=Thewissen, J. G. M. |year=2009|title=Encyclopedia of Marine Mammals|publisher=Academic Press|edition=2nd|isbn=978-0-12-373553-9|chapter=The leopard seal, Hydrurga leptonyx|last1=Rogers|first1=Tracey L.}}
• Heacox, Kim. (2006). [https://web.archive.org/web/20071123043610/http://www7.nationalgeographic.com/ngm/0611/feature2/ Deadly Beauty.] National Geographic, November 2006
• Saundry, Peter. (2010) [http://www.eoearth.org/wiki/Leopard_seal Leopard Seal.] Encyclopedia of Earth. Topic ed. C. Michael Hogan, editor-in-chief Cutler Cleveland, NCSE, Washington DC

{{Portal|Marine life|Mammals}}

{{Commons|Hydrurga leptonyx|Leopard Seal}}

{{Wikispecies|Hydrurga leptonyx}}

{{NIE Poster|Sea-leopard}}

• [https://web.archive.org/web/20051028045950/http://news.nationalgeographic.com/news/2005/10/photogalleries/best_animal_photos/photo2.html Best Wildlife Photos of 2005 – "Underwater World" Winner: "Leopard Seal Pass"]
• [https://www.youtube.com/watch?v=Zxa6P73Awcg "Face-off with a deadly predator"] (video); National Geographic photo assignment
• [http://cetus.ucsd.edu/voicesinthesea_org/species/pinnipeds/leopardSeal.html Voices in the Sea – the Leopard Seal] {{Webarchive|url=https://web.archive.org/web/20140709234301/http://cetus.ucsd.edu/voicesinthesea_org/species/pinnipeds/leopardSeal.html |date=2014-07-09 }} (audio)

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Category:Lobodontins

Category:Pinnipeds of Antarctica

Category:Pinnipeds of South America

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Category:Mammals of Chile

Category:Mammals of South Australia

Category:Fauna of Heard Island and McDonald Islands

Category:Least concern biota of Oceania

Category:Least concern biota of South America

Category:Mammals described in 1820

Category:Extant Zanclean first appearances

Category:Pliocene mammals of South America

Category:Pliocene pinnipeds

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