Animal Diversity Web

Ge­o­graphic Range

Leop­ard seals (Hy­drurga lep­tonyx) are pre­dom­i­nately found in the cir­cum­po­lar re­gion of the Antarc­tic pack ice. Al­though small num­bers can be found just be­yond the pack ice on the nearby sub­antarc­tic is­lands year-round, there is greater dis­per­sal into this area dur­ing the win­ter months. (Orit­s­land, 1970; Rogers, 2009)

• Biogeographic Regions
• antarctica
  • native
• indian ocean
  • native
• atlantic ocean
  • native
• pacific ocean
  • native

Habi­tat

Leop­ard seals re­side mostly on and around the pack ice of Antarc­tica, but may also be seen on the sub­antarc­tic is­lands if there is enough ice sub­strate. These seals are much more agile in the water than on ice, and water is where they spend much of their time. Leop­ard seals feed on species that re­side in the sur­face wa­ters of the ocean, and thus are found pri­mar­ily in these wa­ters. (Jes­sopp, et al., 2004; Laws, 1984; Orit­s­land, 1970)

• Habitat Regions
• polar
• saltwater or marine

• Terrestrial Biomes
• icecap

Phys­i­cal De­scrip­tion

Leop­ard seals are by far the largest of the antarc­tic seals. Males can grow up to 3 me­ters in length and weigh ap­prox­i­mately 300 kg. Fe­males are even larger, grow­ing up to 3.8 me­ters in length and 500 kg. The over­all body shape of leop­ard seals are long and slen­der, mak­ing it very agile in the water. Their col­or­ing varies dor­sally to ven­trally with a dark grey back, a sil­very grey un­der­side, and dark and light spots through­out the en­tire body. The snout of leop­ard seals are long on their large head; well-de­signed for catch­ing and han­dling prey. (Ray, 1970; Rogers, 2009)

• Other Physical Features
• endothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger

• Range mass

  300 to 500 kg

  660.79 to 1101.32 lb

• Range length

  3 to 3.8 m

  9.84 to 12.47 ft

Re­pro­duc­tion

Lit­tle is known about leop­ard seal mat­ing sys­tems, be­cause they in­habit an ex­treme en­vi­ron­ment mak­ing di­rect ob­ser­va­tion dif­fi­cult. Much of what is known was ob­served from cap­tive in­di­vid­u­als. Lit­tle is known about mate ac­qui­si­tion in leop­ard seals, but vo­cal­iza­tion is thought to play a role as males be­come highly vocal dur­ing the breed­ing sea­son. Mat­ing oc­curs in the water in cap­tive en­vi­ron­ments and wild pop­u­la­tions are thought to be­have sim­i­larly. After mat­ing the fe­male is left alone to wean the pups on the ice. (Rogers, 2009)

• Mating System
• polygynous

Birth of leop­ard seal pups gen­er­ally oc­curs be­tween late Oc­to­ber and No­vem­ber, with new­born pups mea­sur­ing on av­er­age 120 cm in length. For the next 4 weeks, the mother nurses her pups on an ice flow. Mat­ing oc­curs dur­ing De­cem­ber and into the be­gin­ning of Jan­u­ary shortly after the pups are weaned. (Jef­fer­son, et al., 1993; Orit­s­land, 1970; Rogers, 2009; Siniff, 1991)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• Breeding interval

  Leopard seals breed once yearly.

• Breeding season

  The breeding lasts from December to early January.

• Range number of offspring

  1 (high)

• Average number of offspring

  1

• Average number of offspring

  1

  AnAge

• Average gestation period

  274 days

  AnAge

• Range weaning age

  4 (high) weeks

• Average age at sexual or reproductive maturity (female)

  4 years

• Average age at sexual or reproductive maturity (female)
  Sex: female

  1095 days

  AnAge

• Average age at sexual or reproductive maturity (male)

  4.5 years

• Average age at sexual or reproductive maturity (male)
  Sex: male

  1461 days

  AnAge

Leop­ard seals live a soli­tary life with the ex­cep­tion of a brief mat­ing pe­riod, so there is lit­tle in­for­ma­tion de­scrib­ing mat­ing in­ter­ac­tions of males and fe­males. It is, how­ever, known that males do not pro­vide any post-fer­til­iza­tion parental in­vest­ment once they have mated with a fe­male. (Rogers, 2009)

Fe­male leop­ard seals are solely re­spon­si­ble for their pup once it is born. On the ice floes of Antarc­tica mother seals are seen nurs­ing and pro­tect­ing their young for ap­prox­i­mately 4 weeks fol­low­ing birth. After these 4 weeks, the pup is weaned and shortly after fe­males begin mat­ing again. After the wean­ing pe­riod, there is not much known about leop­ard seal de­vel­op­ment. Ju­ve­nile leop­ard seals have, how­ever, been ob­served in rel­a­tively large num­bers on the nearby sub­antarc­tic is­lands. (Rogers, 2009; Siniff, 1991)

• Parental Investment
• female parental care
• pre-fertilization
  • provisioning
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female

Lifes­pan/Longevity

There are few ac­counts of the lifes­pan of leop­ard seals. How­ever, they have been recorded to live for up to 30 years in the wild, but the lifes­pan is spec­u­lated to be closer to 26 years. (Orit­s­land, 1970; Rogers, 2009)

• Range lifespan
  Status: wild

  30 (high) years

• Average lifespan
  Status: wild

  26 years

• Average lifespan
  Status: wild

  26.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Sex: male
  Status: wild

  23.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Sex: female
  Status: wild

  26.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

Leop­ard seals are a soli­tary species ex­clud­ing mat­ing and nurs­ing pe­ri­ods. As mat­ing sea­son ap­proaches, the den­sity of seals on and around packs of ice in­creases. Den­sity on pack ice also in­creases when pups are born, as that is where moth­ers give birth and nurse their young. Oth­er­wise leop­ard seals pre­dom­i­nately in­habit the water. (Laws, 1984; Rogers, 2009; Siniff, 1991)

• Key Behaviors
• natatorial
• diurnal
• motile
• migratory
• solitary

Home Range

The home range of leop­ard seals is con­fined mostly to the pack ice, be­cause of mat­ing. Through­out the year are also found on the nearby sub­antarc­tic is­lands in mod­er­ately low num­bers. How­ever, this greatly in­creases dur­ing the win­ter months dur­ing the seal mi­gra­tion pe­riod. (Jes­sopp, et al., 2004; Orit­s­land, 1970; Rogers, 2009)

Com­mu­ni­ca­tion and Per­cep­tion

Not much is known re­gard­ing com­mu­ni­ca­tion among leop­ard seals. How­ever, males are known to vo­cal­ize just prior to and dur­ing the mat­ing sea­son. It is sus­pected that these sounds are used for mate at­trac­tion. (Opzee­land, et al., 2010)

• Communication Channels
• acoustic

• Perception Channels
• tactile
• acoustic
• chemical

Food Habits

Leop­ard seals feed pri­mar­ily on krill, using their lo­bodont teeth to fil­ter these small crus­taceans from the water. Al­though krill are their pri­mary food source, leop­ard seals are also ag­gres­sive apex preda­tors eat­ing pen­guins, young crabeater seals, and squid. (Berk­man, 2001; Rogers, 2009)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • eats non-insect arthropods
  • molluscivore

• Animal Foods
• birds
• mammals
• fish
• mollusks
• aquatic crustaceans

• Foraging Behavior
• filter-feeding

Pre­da­tion

Leop­ard seals are apex preda­tors, in­di­cat­ing that they are at the top of the Antarc­tic food chain. Their only known nat­ural preda­tors are killer whales, how­ever leop­ard seals are rarely eaten. (Berk­man, 2001)

• Known Predators

  • Killer Whales (Orcinus orca)

Ecosys­tem Roles

As apex preda­tors, leop­ard seals play an im­por­tant eco­log­i­cal role feed­ing on large an­i­mals that in­habit the ex­treme antarc­tic sys­tem. (Rogers, 2009)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

There are few in­ter­ac­tions be­tween hu­mans and leop­ard seals, how­ever they are used for sci­en­tific re­search and ed­u­ca­tion. (Jef­fer­son, et al., 1993)

• Positive Impacts
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Leop­ard seals have no ob­served neg­a­tive eco­nomic ef­fects on hu­mans. (Jef­fer­son, et al., 1993)

Con­ser­va­tion Sta­tus

Ac­cord­ing to the IUCN Red List, leop­ard seals are at lower risk and of least con­cern. How­ever, a de­cline in antarc­tic pack ice will likely to be im­pact the species. ("2008 Pa­cific is­lands red list for an­i­mals", 2008)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Other Com­ments

The sci­en­tific name of leop­ard seals, Hy­drurga lep­tonyx, lit­er­ally trans­lated means 'slen­der-clawed wa­ter-worker'. (Rogers, 2009)

Con­trib­u­tors

Anna Hill (au­thor), Michi­gan State Uni­ver­sity, Bar­bara Lun­dri­gan (ed­i­tor), Michi­gan State Uni­ver­sity, Laura Podzikowski (ed­i­tor), Spe­cial Pro­jects.

Ref­er­ences

2008. "2008 Pa­cific is­lands red list for an­i­mals" (On-line). IUCN.​org. Ac­cessed March 11, 2012 at http://​cmsdata.​iucn.​org/​downloads/​appendix_​1_​animals_​of_​the_​pacific_​islands_​listed_​on_​the_​2008_​red_​list.​pdf.

Berk­man, P. 2001. Sci­ence into Pol­icy : Global Lessons from Antarc­tica. Burling­ton, MA: Aca­d­e­mic Press.

Jef­fer­son, T., S. Leather­wood, M. Web­ber. 1993. Ma­rine Mam­mals of the World. Roome: United Na­tions En­vi­ron­ment Pro­gramme, Food and Agri­cul­ture Or­ga­ni­za­tion of the United Na­tions.

Jes­sopp, M., J. Reid, P. Trathan, E. Mur­phy. 2004. Win­ter dis­per­sal of leop­ard seals (Hy­drurga lep­tonyx): en­vi­ron­men­tal fac­tors in­flu­enc­ing de­mo­graph­ics and sea­sonal abun­dance. Jour­nal of Zo­ol­ogy, 263: 251-258.

Laws, R. 1984. Antarc­tic Ecol­ogy Vol. II. Lon­don: Aca­d­e­mic Press.

Opzee­land, I., S. Par­ijs, H. Borne­mann, S. Frick­en­haus, L. Kin­der­mann, H. Klinck, J. Plotz, O. Boebel. 2010. Acoustic ecol­ogy of Antarc­tic pin­nipeds. Ma­rine Ecol­ogy Progress Se­ries, 414: 267-291.

Orit­s­land, T. 1970. Bi­ol­ogy and Pop­u­la­tion Dy­nam­ics of Antarc­tic Seals. Pp. 361-366 in M Holdgate, ed. Antarc­tic Ecol­ogy, Vol. I. Lon­don: Aca­d­e­mic Press.

Ray, C. 1970. Pop­u­la­tion Ecol­ogy of Antarc­tic Seals. Pp. 398-414 in M Holdgate, ed. Antarc­tic Ecol­ogy, Vol. 1. Lon­don, New York: Aca­d­e­mic Press.

Rogers, T. 2009. "Leop­ard seal (H. lep­tonyx)" (On-line). The So­ci­ety for Ma­rine Mam­mal­ogy. Ac­cessed March 11, 2012 at http://​www.​marinemammalscience.​org/​index.​php?​option=com_​content&​view=article&​id=459&​Itemid=298.

Siniff, D. 1991. An Overview of the Ecol­ogy of Antarc­tic Seals. Amer­i­can Zo­ol­o­gist, 31: 143-149.