Editing Earless seal

{{Short description|Family of mammals}}
{{distinguish|text=[[Phocides]], a genus of butterflies, [[Pholcidae]], a family of spiders, or [[Phocoenidae]], a family of toothed whales}}
{{Automatic taxobox
| name = Earless seals<ref name=msw3>{{MSW3 Wozencraft | pages = | id = 14001028}}</ref>
| image = Seehund.jpg
| image_caption = [[Harbor seal]], ''Phoca vitulina''
| fossil_range = {{Fossil range|earliest=Chattian|Aquitanian|present}}<small>Early [[Miocene]] – [[Holocene]], possible late [[Oligocene]] record<ref name=Noriphoca>{{Cite journal|author1=Leonard Dewaele |author2=Olivier Lambert |author3=Stephen Louwye |year=2018 |title=A critical revision of the fossil record, stratigraphy and diversity of the Neogene seal genus ''Monotherium'' (Carnivora, Phocidae) |journal=Royal Society Open Science |volume=5 |issue=5 |pages=171669 |doi=10.1098/rsos.171669 |pmid=29892365 |pmc=5990722 |bibcode=2018RSOS....571669D }}</ref></small>
| taxon = Phocidae
| authority = [[John Edward Gray|Gray]], 1821
| type_genus = ''[[Phoca]]''
| type_genus_authority = [[Carl Linnaeus|Linnaeus]], 1758
| subdivision_ranks = Subfamilies
| subdivision = 
*†[[Devinophoca|Devinophocinae]]
*[[Monachinae]]
*[[Phocinae]]
}}

The '''earless seals''', '''phocids''', or '''true seals''' are one of the three main groups of [[mammal]]s within the seal lineage, [[Pinniped]]ia. All true seals are members of the family '''Phocidae''' ({{IPAc-en|ˈ|f|oʊ|s|ᵻ|d|iː}}). They are sometimes called '''crawling seals''' to distinguish them from the [[fur seal]]s and [[sea lion]]s of the family [[Eared seal|Otariidae]]. Seals live in the [[ocean]]s of both hemispheres and, with the exception of the more [[tropical]] [[monk seal]]s, are mostly confined to [[Polar region|polar]], subpolar, and [[temperate]] climates.  The [[Baikal seal]] is the only species of exclusively [[freshwater seal]].

==Taxonomy and evolution==

===Evolution===
[[File:Cranio Pliophoca etrusca, Orciano.JPG|thumb|Fossil ''[[Pliophoca]]'' skull]] 

The earliest known fossil earless seal is ''[[Noriphoca]] gaudini'' from the late [[Oligocene]] or earliest [[Miocene]] ([[Aquitanian (stage)|Aquitanian]]) of [[Italy]].<ref name=Noriphoca /> Other early fossil phocids date from the mid-Miocene, 15 million years ago in the north Atlantic.<ref name=Noriphoca /><ref>{{Cite journal|last1=Dewaele|first1=Leonard|last2=Lambert|first2=Olivier|last3=Louwye|first3=Stephen|date=2017-02-21|title=On ''Prophoca'' and ''Leptophoca'' (Pinnipedia, Phocidae) from the Miocene of the North Atlantic realm: redescription, phylogenetic affinities and paleobiogeographic implications|journal=PeerJ|language=en|volume=5|pages=e3024|doi=10.7717/peerj.3024|pmid=28243538|doi-access=free|pmc=5322758}}</ref> Until recently, many researchers believed that phocids evolved separately from [[otariids]] and [[Walrus|odobenids]]; and that they evolved from [[otter]]-like animals, such as ''[[Potamotherium]]'', which inhabited European freshwater lakes. Recent evidence strongly suggests a monophyletic origin for all pinnipeds from a single ancestor, possibly ''[[Enaliarctos]]'', most closely related to the [[Mustelidae|mustelids]] and [[bear]]s.<ref>{{Cite journal|last1=Paterson|first1=Ryan S.|last2=Rybczynski|first2=Natalia|last3=Kohno|first3=Naoki|last4=Maddin|first4=Hillary C.|date=2020|title=A Total Evidence Phylogenetic Analysis of Pinniped Phylogeny and the Possibility of Parallel Evolution Within a Monophyletic Framework|journal=Frontiers in Ecology and Evolution|language=en|volume=7|doi=10.3389/fevo.2019.00457|doi-access=free}}</ref>

[[Monk seal]]s and [[elephant seal]]s were previously believed to have first entered the Pacific through the open straits between North and South America,<ref name="Fulton-2010" /> with the Antarctic true seals either using the same route or travelled down the west coast of Africa.<ref>{{cite book |author1=Savage, RJG |author2= Long, MR |name-list-style=amp|year=1986 |title= Mammal Evolution: an illustrated guide|url=https://archive.org/details/mammalevolutioni0000sava |url-access=registration |publisher= Facts on File|location=New York|pages= [https://archive.org/details/mammalevolutioni0000sava/page/94 94–95]|isbn= 978-0-8160-1194-0}}</ref> It is now thought that the [[monk seal]]s, [[elephant seal]]s, and [[Lobodontini|Antarctic seals]] all evolved in the southern hemisphere, and likely dispersed to their current distributions from more southern latitudes.<ref>{{Cite journal|last1=Rule|first1=James P.|last2=Adams|first2=Justin W.|last3=Marx|first3=Felix G.|last4=Evans|first4=Alistair R.|last5=Tennyson|first5=Alan J. D.|last6=Scofield|first6=R. Paul|last7=Fitzgerald|first7=Erich M. G.|date=2020-11-11|title=First monk seal from the Southern Hemisphere rewrites the evolutionary history of true seals|journal=Proceedings of the Royal Society B: Biological Sciences|volume=287|issue=1938|pages=20202318|doi=10.1098/rspb.2020.2318|pmid=33171079|pmc=7735288|doi-access=free}}</ref>

===Taxonomy===

{{Cladogram|align=left|title=
|clade=
{{clade
|style=font-size:75%;line-height:75%;width:500px;
|label1=[[Pinnipedia]]
|1={{clade
   |label1='''Phocidae'''
   |1={{clade
      |label1=[[Phocinae]]
      |1={{clade
         |1=[[Bearded seal]]<!-- Erignathus barbatus -->
         |2={{clade
            |1=[[Hooded seal]]<!-- Cystophora cristata -->
            |label2=Phocini
            |2={{clade
               |1={{clade
                  |1={{clade
                     |1={{clade
                        |1={{clade
                           |1=[[Ringed seal]]<!-- Pusa hispida -->
                           |2=[[Baikal seal]]<!-- Pusa sibirica -->
                           }}
                        |2=[[Caspian seal]]<!-- Pusa caspica -->
                        }}
                     |2={{clade
                        |1=[[Spotted seal]]<!-- Phoca largha -->
                        |2=[[Harbor seal]]<!-- Phoca vitulina -->
                        }}
                     }}
                  |2=[[Grey seal]]<!-- Halichoerus grypus-->
                  }}
               |2={{clade
                  |1=[[Ribbon seal]]<!-- Histriophoca fasciata) -->
                  |2=[[Harp seal]]<!-- Pagophilus groenlandicus -->
                  }}
               }}
            }}
         }}
      |label2=[[Monachinae]]
      |2={{clade
         |1={{clade
            |label1=Lobodontini
            |1={{clade
               |1={{clade
                  |1={{clade
                     |1=[[Weddell seal]]<!-- Leptonychotes weddellii -->
                     |2=[[Leopard seal]]<!-- Hydrurga leptonyx-->
                     }}
                  |2=[[Crabeater seal]]<!-- Lobodon carcinophaga -->
                  }}
               |2=[[Ross seal]]<!-- Ommatophoca rossii -->
               }}
            |label2=Miroungini|sublabel2=(elephant seals)
            |2={{clade
               |1=[[Southern elephant seal]]<!-- Mirounga leonina -->
               |2=[[Northern elephant seal]]<!-- Mirounga angustirostris -->
               }}
            }}
         |label2=Monachini
         |2={{clade
            |1=[[Mediterranean monk seal]]<!-- Monachus monachus -->
            |2=[[Hawaiian monk seal]]<!-- Neomonachus schauinslandi -->
            |3=[[Caribbean monk seal]]
            }}
         }}
      }}
   |2={{clade
      |1=[[Otariidae]] ([[eared seal]]s)
      |2=[[Odobenidae]] ([[Walrus]])
      }}
   }}
}}
|caption=[[Cladogram]] showing relationships among the phocids, combining several phylogenetic analyses.<ref name="Berta Churchill Boessenecker 2018">{{cite journal | last1=Berta | first1=Annalisa | last2=Churchill | first2=Morgan | last3=Boessenecker | first3=Robert W. | title=The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses | journal=Annual Review of Earth and Planetary Sciences | publisher=Annual Reviews | volume=46 | issue=1 | date=2018-05-30 | issn=0084-6597 | doi=10.1146/annurev-earth-082517-010009 | pages=203–228| bibcode=2018AREPS..46..203B | s2cid=135439365 | doi-access=free }}</ref>
}}

In the 1980s and 1990s, morphological [[phylogenetics|phylogenetic]] analysis of the phocids led to new conclusions about the interrelatedness of the various genera. More recent molecular phylogenetic analyses have confirmed the [[monophyly]] of the two phocid subfamilies ([[Phocinae]] and Monachinae).<ref>{{Cite journal|last1=Árnason|first1=Úlfur|last2=Bodin|first2=Kristina|last3=Gullberg|first3=Anette|last4=Ledje|first4=Christina|last5=Suzette|first5=Mouchaty|date=1995|title=A molecular view of pinniped relationships with particular emphasis on the true seals|journal=Journal of Molecular Evolution|volume=40 |issue=1 |pages=78–85|doi=10.1007/BF00166598|pmid=7714914 |bibcode=1995JMolE..40...78A |s2cid=7537924}}</ref><ref>{{Cite journal|last1=Arnason |first1=Ulfur |last2=Gullberg |first2=Anette |last3=Janke|first3=Axel |last4=Kullberg|first4=Morgan |last5=Lehman |first5=Niles |last6=Petrov |first6=Evgeny A.|last7=Väinölä|first7=Risto|date=2006-11-01 |title=Pinniped phylogeny and a new hypothesis for their origin and dispersal|journal=Molecular Phylogenetics and Evolution |volume=41|issue=2 |pages=345–354|doi=10.1016/j.ympev.2006.05.022 |pmid=16815048|bibcode=2006MolPE..41..345A }}</ref><ref>{{Cite journal|last1=Fulton|first1=Tara Lynn|last2=Strobeck|first2=Curtis |date=2010|title=Multiple markers and multiple individuals refine true seal phylogeny and bring molecules and morphology back in line |journal=Proceedings of the Royal Society B: Biological Sciences  |volume=277 |issue=1684 |pages=1065–1070 |doi=10.1098/rspb.2009.1783|pmc=2842760|pmid=19939841}}</ref><ref name="Fulton-2010">{{Cite journal |last1=Fulton |first1=Tara L. |last2=Strobeck|first2=Curtis |date=2010|title=Multiple fossil calibrations, nuclear loci and mitochondrial genomes provide new insight into biogeography and divergence timing for true seals (Phocidae, Pinnipedia) |journal=Journal of Biogeography |volume=37|issue=5 |pages=814–829 |doi=10.1111/j.1365-2699.2010.02271.x|bibcode=2010JBiog..37..814F |s2cid=59436229 }}</ref> The Monachinae (known as the "southern" seals), is composed of three tribes; the Lobodontini, Miroungini, and Monachini. The four [[Antarctic]] genera ''[[leopard seal|Hydrurga]]'', ''[[Weddell seal|Leptonychotes]]'', ''[[crabeater seal|Lobodon]]'', and ''[[Ross seal|Ommatophoca]]'' are part of the [[tribe (biology)|tribe]] [[Lobodontini]]. Tribe Miroungini is composed of the [[elephant seal]]s. The [[Monk seal]]s (''[[Mediterranean monk seal|Monachus]]'' and ''[[Neomonachus]]'') are all part of the tribe Monachini.<ref>{{Cite journal |last1=Scheel |first1=Dirk-Martin|last2=Slater|first2=Graham J.|last3=Kolokotronis|first3=Sergios-Orestis |last4=Potter |first4=Charles W.|last5=Rotstein|first5=David S.|last6=Tsangaras|first6=Kyriakos |last7=Greenwood|first7=Alex D.|last8=Helgen|first8=Kristofer M.|date=2014|title=Biogeography and taxonomy of extinct and endangered monk seals illuminated by ancient DNA and skull morphology |journal=ZooKeys|issue=409 |pages=1–33|doi=10.3897/zookeys.409.6244|pmc=4042687|pmid=24899841|doi-access=free|bibcode=2014ZooK..409....1S }}</ref> Likewise, subfamily Phocinae (the "northern" seals) also includes three tribes; Erignathini (''[[bearded seal|Erignathus]])'', Cystophorini (''[[hooded seal|Cystophora)]]'', and [[Phocini]] (all other phocines). More recently, five species have been split off from ''Phoca'', forming three additional genera.<ref>{{Cite journal|last1=Berta|first1=Annalisa |last2=Churchill|first2=Morgan|date=2012 |title=Pinniped taxonomy: review of currently recognized species and subspecies, and evidence used for their description|journal=Mammal Review |volume=42 |issue=3|pages=207–234 |doi=10.1111/j.1365-2907.2011.00193.x|bibcode=2012MamRv..42..207B }}</ref>

Alternatively the three monachine tribes have been evaluated to familiar status, which elephant seals and the Antarctic seals are more closely related to the phocines.<ref name="Bonner1994">{{cite book | last1 = Bonner | first1 = N. | year = 1994| title = Seals and Sea Lions of the World | publisher = Blandford |location= United Kingdom | pages = 1–224 |isbn = 9780816057177}}</ref>
{{-}}

===Extant genera===
{| class="wikitable"
|-
! Subfamily!! Tribe !! Image !! Genus !! species
|-
! rowspan="7"  style="text-align:center;"| '''Subfamily [[Monachinae]]'''
! rowspan="2"  style="text-align:center;"| '''Tribe [[Monachini]]'''
|[[File:Monachus monachus.jpg|175px]] ||''[[Monachus]]'' <small>Fleming, 1822</small> || 
* [[Mediterranean monk seal]], ''Monachus monachus''
|-
|[[File:Monachus schauinslandi.jpg|175px]] ||''[[Neomonachus]]'' <small>Slater & Helgen, 2014</small> || 
*[[Hawaiian monk seal]], ''Neomonachus schauinslandi''
* †[[Caribbean monk seal]], ''Neomonachus  tropicalis'' (probably extinct around 1952)
|-
! rowspan="1"  style="text-align:center;"| '''Tribe Miroungini'''
|[[File:Mirounga angustirostris, Point Reyes (cropped).jpg|175px]] ||''[[Mirounga]]'' <small>Gray, 1827</small> || 
* [[Northern elephant seal]], ''Mirounga angustirostris''
* [[Southern elephant seal]], ''Mirounga leonina''
|-
! rowspan="4"  style="text-align:center;"| '''Tribe [[Lobodontini]]'''
|[[File:Ross-seal.jpg|175px]] ||''[[Ommatophoca]]'' <small>Gray, 1844</small> || 
* [[Ross seal]], ''Ommatophoca rossi''
|-
|[[File:Antarctica 2013 Journey to the Crystal Desert (8369556693).jpg|175px]] ||''[[Lobodon]]'' <small>Gray, 1844</small> ||
* [[Crabeater seal]], ''Lobodon carcinophagus''
|-
|[[File:Leopard seal basking on Iceberg.jpg|175px]] ||''[[Hydrurga]]'' <small>Gistel, 1848</small> || 
* [[Leopard seal]], ''Hydrurga leptonyx''
|-
|[[File:Weddell Seal in Antarctica (8381225741).jpg|175px]] ||''[[Leptonychotes]]'' <small>Gill, 1872</small> ||
* [[Weddell seal]], ''Leptonychotes weddellii''
|-
! rowspan="7"  style="text-align:center;"| '''Subfamily [[Phocinae]]'''
! rowspan="1"  style="text-align:center;"| '''Tribe Cystophorini'''
|[[File:2016-klappmützemuseumkoenig.jpg|175px]] ||''[[Cystophora (mammal)|Cystophora]]'' <small>Nilsson, 1820</small> || 
* [[Hooded seal]], ''Cystophora cristata''
|-
! rowspan="1"  style="text-align:center;"| '''Tribe Erignathini'''
|[[File:Bearded Seal at Svalbard (cropped).jpg|175px]] ||''[[Erignathus]]'' <small>Gill, 1866</small> || 
* [[Bearded seal]], ''Erignathus barbatus''
|-
! rowspan="5"  style="text-align:center;"| '''Tribe Phocini'''
|[[File:Seehund2cele4.jpg|175px]] ||''[[Phoca]]'' <small>Linnaeus, 1758</small> || 
* [[Harbor seal]] or common seal, ''Phoca vitulina''
* [[Spotted seal]], ''Phoca largha''
|-
|[[File:Pusa hispida hispida NOAA 1.jpg|175px]] ||''[[Pusa]]'' <small>Scopoli, 1771</small> || 
* [[Ringed seal]], ''Pusa hispida'' (formerly ''Phoca hispida'')
* [[Baikal seal]], ''Pusa sibirica'' (formerly ''Phoca sibirica'')
* [[Caspian seal]], ''Pusa caspica'' (formerly ''Phoca caspica'')
|-
|[[File:Harp seal at False Cape (cut).jpg|175px]] ||''[[Pagophilus]]'' <small>Gray, 1844</small> || 
* [[Harp seal]], ''Pagophilus groenlandicus'' (formerly ''Phoca groenlandica'')
|-
|[[File:Ribbon-seal-male Josh London NOAAedit (16086029928) (cropped).jpg|175px]] ||''[[Histriophoca]]'' <small>Gill, 1873</small> || 
* [[Ribbon seal]], ''Histriophoca fasciata'' (formerly ''Phoca fasciata'')
|-
|[[File:Halichoerus grypus He3.jpg|175px]] ||''[[Halichoerus]]'' <small>Nilsson, 1820</small> || 
* [[Grey seal]], ''Halichoerus grypus''
|-
|}

==Biology==

===External anatomy===

[[File:Harbor seal with skeleton GS.jpg|thumb|Skeletal anatomy of a harbor seal. 1. Skull. 2. Spine. 3. Tail. 4. Hindlimb. 5. Forelimb. 6. Shoulder. 7. Pelvis. 8. Rib cage.]]
[[File:Phoca vitulina 02 MWNH 1464.JPG|thumb|left|[[Harbor seal]] skull (''Phoca vitulina'')]]

Adult phocids vary from {{convert|1.17|m|ft|abbr=on}} in length and {{convert|45|kg|lb|abbr=on}} in weight in the [[ringed seal]] to {{convert|5.8|m|ft|abbr=on}} and {{convert|4000|kg|lb|abbr=on}} in the [[southern elephant seal]], which is the largest member of the order [[Carnivora]]. Phocids have fewer teeth than land-based members of the [[Carnivora]], although they retain powerful [[canine tooth|canines]]. Some species lack [[Molar (tooth)|molar]]s altogether. The [[dentition|dental formula]] is:
{{DentalFormula|upper=2–3.1.4.0–2|lower=1–2.1.4.0–2}}

While otariids are known for speed and maneuverability, phocids are known for efficient, economical movement. This allows most phocids to forage far from land to exploit prey resources, while otariids are tied to rich [[upwelling]] zones close to breeding sites. Phocids swim by sideways movements of their bodies, using their hind flippers to fullest effect.<ref name=EoM>{{cite book|editor= Macdonald, D.|author= McLaren, Ian|year= 1984|title= The Encyclopedia of Mammals|publisher= Facts on File|location= New York|pages= [https://archive.org/details/encyclopediaofma00mals_0/page/270 270–275]|isbn= 978-0-87196-871-5|url-access= registration|url= https://archive.org/details/encyclopediaofma00mals_0/page/270}}</ref> Their fore flippers are used primarily for steering, while their hind flippers are bound to the [[pelvis]] in such a way that they cannot bring them under their bodies to walk on them. They are more streamlined than fur seals and sea lions, so they can swim more effectively over long distances. However, because they cannot turn their hind flippers downward, they are very clumsy on land, having to wriggle with their front flippers and abdominal [[muscle]]s.

[[File:Seal kidney-- FMVZ USP-08.jpg|thumb|Seal kidney]]

Phocid respiratory and circulatory systems are adapted to allow diving to considerable depths, and they can spend a long time underwater between breaths. Air is forced from the [[lung]]s during a dive and into the upper respiratory passages, where gases cannot easily be absorbed into the bloodstream. This helps protect the seal from [[Decompression sickness|the bends]]. The [[middle ear]] is also lined with blood sinuses that inflate during diving, helping to maintain a constant pressure.<ref name=EoM/>

Phocids are more specialized for [[Aquatic animal|aquatic]] life than otariids. They lack external ears and have sleek, streamlined bodies. Retractable [[nipple]]s, internal [[testicle]]s,<ref name="PerrinWürsig2009">{{cite book|author1=Perrin, William F. |author2=Würsig, Bernd |author3= Thewissen, J.G.M.|title=Encyclopedia of Marine Mammals|url=https://books.google.com/books?id=2rkHQpToi9sC&q=phocid+OR+phocidae|date=2009|publisher=Academic Press|isbn=978-0-08-091993-5}}</ref> and an internal [[penile sheath]] provide further streamlining. A smooth layer of [[blubber]] lies underneath the skin. Phocids are able to divert [[blood]] flow to this layer to help control their temperatures.<ref>{{Cite journal|last1=Favilla|first1=Arina B.|last2=Costa|first2=Daniel P.|date=2020-09-11|title=Thermoregulatory Strategies of Diving Air-Breathing Marine Vertebrates: A Review|journal=Frontiers in Ecology and Evolution|volume=8|pages=555509|doi=10.3389/fevo.2020.555509|issn=2296-701X|doi-access=free}}</ref>

===Communication===
Unlike otariids, true seals do not communicate by "barking". Instead, they communicate by slapping the water and grunting. True seals have also been documented to clap at each other underwater.<ref>{{cite web|last1=Hocking|first1=David|last2=Burnville|first2=Ben|last3=Marx|first3=Felix Georg|url=https://www.ncl.ac.uk/press/articles/archive/2020/02/conversationsealsclapping/|title=Comment: Grey seals discovered clapping underwater to communicate|work=[[The Conversation]]|via=[[Newcastle University]]|date=February 3, 2020|accessdate=April 15, 2025}}</ref> One study published in ''[[Animal Behaviour (journal)|Animal Behaviour]]'' found that seals use rhythmic [[percussive]] signalling in both "agonistic interactions" and display behavior.<ref>{{cite journal |last1=Kocsis |first1=Kinga |last2=Duengen |first2=Diandra |last3=Jadoul |first3=Yannick |last4=Ravignani |first4=Andrea |title=Harbour seals use rhythmic percussive signalling in interaction and display |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |date=January 2024 |volume=207 |pages=223–234 |doi=10.1016/j.anbehav.2023.09.014 |bibcode=2024AnBeh.207..223K }}</ref>

===Movements===
With short front flippers and because their rear flipper is unable to rotate, true seals cannot walk when out of the water like sea lions. As a result, they bounce themselves forward in a motion called ''[[wikt:galumphing|galumphing]]'';<ref>{{cite book|last=Dipper|first=Frances|title=[[Royal Society for the Protection of Birds|RSPB]] Spotlight: Seals|page=20|publisher=[[Bloomsbury Publishing|Bloomsbury Wildlife]]|location=[[London]]|isbn=978-1-4214-0305-2|date=2021}}</ref><ref>{{cite book|last=Derocher|first=Andrew E.|title=Polar Bears: A Complete Guide to Their Biology and Behavior|page=73|publisher=[[Johns Hopkins University Press]]|location=[[Baltimore]]|isbn=978-1-4214-0305-2|date=2012}}</ref> the polar explorer [[Edward Wilson (explorer)|Edward Wilson]] referred to the motion as ''lolloping''.<ref>{{cite book|last=Schmidt|first=Jeremy|title=Weddell Seals: Science, Life History, and Population Dynamics|page=59|publisher=Weddell Seal Science|isbn=978-1-881480-19-8|date=2023}}</ref>

===Reproduction===
[[File:Earless seal (Puerto Madryn, Argentina).jpg|thumb|left|Southern elephant seals in Argentina|alt=Photo of seven adult and juvenile southern elephant seals packed closely on beach]]
[[File:Pusa hispida saimensis ca 1956.jpg|thumb|Living only in [[Lake Saimaa]], [[Finland]], [[Saimaa ringed seal]]s, a subspecies of [[ringed seal]], are among the most [[Endangered species|endangered]] seals in the world, having a total population of only about 400 individuals.<ref>{{cite web |title= Saimaa Ringed Seal |url= https://wwf.fi/en/saimaaringedseal/  |access-date=22 December 2018}}</ref>]]
<!--[[File:Zwei junge Seehunde am Strand.jpg|thumb|[[Paul de Vos]]:Two young seals on a beach]]-->

Phocids spend most of their time at sea, although they return to land or pack ice to breed and give birth. Pregnant females spend long periods foraging at sea, building up fat reserves, and then return to the breeding site to use their stored energy to nurse pups. However, the common seal displays a reproductive strategy similar to that used by [[Eared seal|otariids]], in which the mother makes short foraging trips between nursing bouts.{{fact|date=April 2025}}

Because a phocid mother's feeding grounds are often hundreds of kilometers from the breeding site, she must [[fasting|fast]] while [[lactation|lactating]]. This combination of fasting with lactation requires the mother to provide large amounts of energy to her pup at a time when she is not eating (and often, not drinking). Mothers must supply their own metabolic needs while nursing. This is a miniature version of the [[humpback whale]]s' strategy, which involves fasting during their months-long migration from arctic feeding areas to tropical breeding/nursing areas and back.{{fact|date=April 2025}}

Phocids produce thick, fat-rich milk that allows them to provide their pups with large amounts of energy in a short period. This allows the mother to return to the sea in time to replenish her reserves. Lactation ranges from five to seven weeks in the [[monk seal]] to just three to five days in the [[hooded seal]]. The mother ends nursing by leaving her pup at the breeding site to search for food (pups continue to nurse if given the opportunity). "Milk stealers" that suckle from unrelated, sleeping females are not uncommon; this often results in the death of the mother's pup, since a female can only feed one pup.{{fact|date=April 2025}}

===Growth and maturation===

The pup's diet is so high in [[Calorie|calories]] that it builds up a fat store. Before the pup is ready to forage, the mother abandons it, and the pup consumes its own fat for weeks or even months while it matures. Seals, like all marine mammals, need time to develop the oxygen stores, swimming muscles, and neural pathways necessary for effective diving and foraging. Seal pups typically eat no food and drink no water during the period, although some polar species eat snow. The postweaning fast ranges from two weeks in the hooded seal to 9–12 weeks in the northern elephant seal.<ref>{{Cite journal|title = The energetics of lactation in the Northern elephant seal, ''Mirounga angustirostris''|journal = Journal of Zoology|date = 1986|pages = 21–33|volume = 209|issue = 1|doi = 10.1111/j.1469-7998.1986.tb03563.x|first1 = D. P.|last1 = Costa|first2 = B. J. Le|last2 = Boeuf|first3 = A. C.|last3 = Huntley|first4 = C. L.|last4 = Ortiz}}</ref> The physiological and behavioral adaptations that allow phocid pups to endure these remarkable fasts, which are among the longest for any mammal, remain an area of active study and research.

=== Feeding strategy ===

Phocids make use of at least four different feeding strategies: suction feeding, grip and tear feeding, filter feeding, and pierce feeding. Each of these feeding strategies is aided by a specialized skull, mandible, and tooth morphology. However, despite morphological specialization, most phocids are opportunistic and employ multiple strategies to capture and eat prey. For example, the leopard seal, ''Hydrurga leptonyx'', uses grip and tear feeding to prey on penguins, suction feeding to consume small fish, and filter feeding to catch krill.<ref>{{Cite journal|last1=Kienle|first1=Sarah S.|last2=Berta|first2=Annalisa|date=2016|title=The better to eat you with: the comparative feeding morphology of phocid seals (Pinnipedia, Phocidae)|journal=Journal of Anatomy|volume=228|issue=3|pages=396–413|doi=10.1111/joa.12410|pmc=5341551|pmid=26646351}}</ref>

==See also==
{{Portal|Mammals|Animals|Marine life}}
* [[Marine mammals as food]]

==References==
{{Reflist}}

{{Carnivora|C1.}}
{{Pan-Pinnipedia|P.|state=autocollapse}}
{{Taxonbar|from=Q25587}}
{{Authority control}}

[[Category:Extant Miocene first appearances]]
[[Category:Pinnipeds]]
[[Category:Taxa named by John Edward Gray]]
[[Category:Non-human celestial navigation]]
[[Category:Taxa described in 1821]]