Mirounga leoninasouthern elephant seal

Geographic Range

Southern elephant seals (Mirounga leonina) inhabit large portions of the southern hemisphere. This includes lands in Antarctica and islands in the southern part of Africa, South America, and Australia. When foraging for food, Southern elephant seals travel between 40 degrees latitude south and the continent of Antarctica. They spend their time in the Pacific, Atlantic, and Indian oceans. They only come to land when they breed, give birth, and take care of their offspring. (Acevedo, et al., 2016; Carrick, et al., 1962; Hofmeyr, 2015; Oceana, 2019)

Habitat

Southern elephant seals live on land only when molting, breeding, and giving birth. When on land, they stay on beaches close to the ocean. They feed in the Pacific, Atlantic, and Indian oceans and can dive up to 1,000 m deep, even reaching the sea floor in areas. When they rest out in the ocean it is on ice. (Acevedo, et al., 2016; Hoff, et al., 2017; Hofmeyr, 2015; Rodhouse, et al., 1992)

  • Terrestrial Biomes
  • icecap
  • Range elevation
    50 (high) m
    164.04 (high) ft
  • Range depth
    200 to 1000 m
    656.17 to 3280.84 ft

Physical Description

In Southern elephant seals, males are bigger than females and grow the signature proboscis on their faces. Older males will usually have more scars on their necks from fighting with other males. Males can grow up to 6 m long and weigh more than 3,700 kg. Females can grow up to just above 2 m long. Both males and females have short, brown fur, but when they molt, it exposes their grey skin. Southern elephant seals are endothermic, meaning they produce their own heat. Their torpedo-like shape and wide rear flippers make them strong swimmers. (Carrick, et al., 1962; Hofmeyr, 2015; Oceana, 2019)

  • Sexual Dimorphism
  • male larger
  • sexes shaped differently
  • ornamentation
  • Range mass
    400 to 3700 kg
    881.06 to 8149.78 lb
  • Range length
    2.8 to 6 m
    9.19 to 19.69 ft
  • Average length
    4.5 m
    14.76 ft

Reproduction

Southern elephant seals form harems of females, which are controlled by one breeding bull if the harem has less than 50 females. As harem size increases to over 50 females, more breeding males control the harem. Breeding bulls protect their harem of females and after 3 to 5 weeks, mating begins. Older and more experienced males usually control harems, but other younger and less experienced bulls may try to intrude and mate with females. (Carrick, et al., 1962)

Southern elephant seals breed once a year. This can occur at the end of September, but usually occurs from mid-to-late October. This time period is when females are in estrus and are most fertile. Females usually give birth to one pup, but on rare occasions they have twins. Elephant seals do not implant eggs until 4 months after mating and all of the pups are born about the same time 7 months later. Female pups weigh 24 to 50 kg at birth and males weigh 27 to 53 pounds at birth. Once pups are born, it takes an average of 22 days for them to become weaned. About 6 to 7 weeks after they are born they are considered independent. Female southern elephant seals reach reproductive maturity between 3 and 6 years old and males reach maturity between 5 and 8 years old. (Anderson, 2003; California Department of Parks and Recreation, 2020; Carrick, et al., 1962)

  • Breeding interval
    Southern elephant seals breed once a year.
  • Breeding season
    Mating can occur at the end of September, but usually occurs mid-to-late October.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Average gestation period
    7 months
  • Average gestation period
    220 days
    AnAge
  • Range weaning age
    18 to 27 days
  • Average weaning age
    22 days
  • Range time to independence
    6 to 7 weeks
  • Average time to independence
    7 weeks
  • Range age at sexual or reproductive maturity (female)
    3 to 6 years
  • Average age at sexual or reproductive maturity (female)
    4 years
  • Range age at sexual or reproductive maturity (male)
    5 to 8 years
  • Average age at sexual or reproductive maturity (male)
    6 years

Female southern elephant seals swim ashore before their pups are born. Once their pups are born, they feed them milk and protect them. After 3 to 5 weeks, females finish weaning their pups. Since it takes about a year to gestate, birth, and wean their pups, mating begins around the same time as weaning. After mating, females go into the ocean to feed and does not return to her pup. Small groups of weaned pups are guarded by bachelor seals, but offspring can sometimes be killed by other adult males. Once all of the adults leave the beach, the pups will eventually venture out to the ocean to look for food once they are hungry. (Anderson, 2003; Carrick, et al., 1962)

  • Parental Investment
  • precocial
  • female parental care
  • pre-fertilization
    • protecting
      • male
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • protecting
      • male

Lifespan/Longevity

Male southern elephant seals can live to be 14 years old while females can live to be 20 years old. On average, southern elephant seals live about 9.5 years. (California Department of Parks and Recreation, 2020; Carrick, et al., 1962; Hofmeyr, 2015)

  • Range lifespan
    Status: wild
    14 to 20 years
  • Typical lifespan
    Status: wild
    14 to 20 years
  • Average lifespan
    Status: wild
    9.5 years

Behavior

The only time southern elephant seals gather in large numbers is when they come back on land to give birth, mate, and molt their fur. While on land, females give birth and nurse their pups for 3 weeks. During that time, older male bulls and mothers will guard the babies. Once pups have been nursing for 3 weeks, males start to form harems and fight over females, which can result in some babies being trampled. Older males fight for control over groups of females and this can include bloody fights, where males will run into one another and bite each other on the neck, leaving gashes and scars. When fighting, males will aim for the proboscis of their opponents and try to pin their opponents to the ground. Losers are forced to retreat. During the day, southern elephant seals may go into torpor to conserve energy. (Carrick, et al., 1962; Hofmeyr, 2015)

  • Average territory size
    71,553,412 km^2

Home Range

Southern elephant seals inhabit a large portion of the southern hemisphere, but major breeding populations are located on sub-Antarctic islands and in Antarctica. They are also found on the Valdes Peninsula in South America. (Acevedo, et al., 2016; Carrick, et al., 1962; Hofmeyr, 2015)

Communication and Perception

Male southern elephant seals will challenge each other by using their proboscises to make a roaring sound. They will also raise up on their hind fins to show off their size. Opponents inspect each other and, if they decide to fight, will lunge at each other with their mouths open. Losers retreat and let out high pitched cries. (Carrick, et al., 1962)

Food Habits

Southern elephant seals are carnivores who mostly eat squids, such as glacial squid (Psychroteuthis glacialis) and smooth hooked squid (Filippovia knipovitchi), as well as various species of fish. Southern elephant seals are able to dive to great depths in the ocean in order to find food. They do not eat during the period when they give birth and mate, so they eat and build up fat stores throughout the rest of the year. These fat stores help them stay warm in the cold ocean water. (Acevedo, et al., 2016; Carrick, et al., 1962; Oceana, 2019)

  • Animal Foods
  • fish
  • mollusks

Predation

Southern elephant seals can sometimes become bycatch in fishing lines and be killed. Their main predators are orcas (Orcinus orca), some big sharks, and leopard seals (Hydrurga leptonyx). Southern elephant seals fight back with their teeth, or swim away when they encounter predator. (Hoff, et al., 2017; Oceana, 2019)

  • Known Predators
    • Killer whale (Orcinus orca) and leopard seal (Hydruga leptonyx)

Ecosystem Roles

Southern elephant seals are large predators in the ocean and feed on other fish and squid. However, this causes a minimal impact on the populations of these species. (Carrick, et al., 1962; Hoff, et al., 2017; Oceana, 2019)

Species Used as Host
  • None
Mutualist Species
  • None
Commensal/Parasitic Species
  • None

Economic Importance for Humans: Positive

Southern elephant seals were hunted by indigenous people in Australia and South America for thousands of years, but from the early 19th century until 1964, they were heavily harvested by commercial companies wanting to turn their blubber into oil. Nowadays, people pay to see them when they are beached and sleeping in the sand. (California Department of Parks and Recreation, 2020; Hofmeyr, 2015)

  • Positive Impacts
  • body parts are source of valuable material
  • ecotourism
  • research and education

Economic Importance for Humans: Negative

Southern elephant seals are large animals, and could potentially kill or harm a person if they were to come too close. Also, deep sea fisheries can have their fishing equipment damaged when southern elephant seals accidentally get caught up in fishing lines. (California Department of Parks and Recreation, 2020)

Conservation Status

According to the IUCN Redlist, southern elephant seals are listed as least concern because their current population has a stable trend, is not severely fragmented, and has had no extreme fluctuations. The southern elephant seal is listed under Appendix II of CITES. (Convention on International Trade in Endangered Species, 2019; Hofmeyr, 2015)

Contributors

Maelan Hauswirth (author), Colorado State University, Brooke Berger (editor), Colorado State University, Galen Burrell (editor).

Glossary

Antarctica

lives on Antarctica, the southernmost continent which sits astride the southern pole.

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

acoustic

uses sound to communicate

benthic

Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

delayed implantation

in mammals, a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months.

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

migratory

makes seasonal movements between breeding and wintering grounds

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

nomadic

generally wanders from place to place, usually within a well-defined range.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

pelagic

An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).

piscivore

an animal that mainly eats fish

polar

the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

polygynous

having more than one female as a mate at one time

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

young precocial

young are relatively well-developed when born

References

Acevedo, J., A. Aguayo-Lobo, J. Brito, D. Torres, B. Cáceres, A. Vila, M. Cardeña, P. Acuña. 2016. Review of the current distribution of southern elephant seals in the eastern South Pacific. New Zealand Journal of Marine and Freshwater Research, Volume 50/ Issue 2: 240-258. Accessed March 10, 2020 at https://www.tandfonline.com/doi/full/10.1080/00288330.2015.1132746.

Anderson, G. 2003. "Elephant Seal Reproduction" (On-line). Marine Science. Accessed March 03, 2020 at http://marinebio.net/marinescience/05nekton/esrepro.htm.

California Department of Parks and Recreation, 2020. "Elephant Seals" (On-line). California Department of Parks and Recreation. Accessed March 03, 2020 at https://www.parks.ca.gov/?page_id=1115.

Carrick, R., S. Csordas, S. Ingham. 1962. "Studies on the Southern Elephant Seal, mirounga leoniata" (On-line pdf). Accessed March 03, 2020 at https://www.publish.csiro.au/wr/pdf/CWR9620161.

Convention on International Trade in Endangered Species, 2019. "Appendices" (On-line). Convention on International Trade in Endangered Species of Wild Fauna and Flora. Accessed March 09, 2020 at https://www.cites.org/eng/app/appendices.php.

Hoff, J., R. Kilpatrick, D. Welsford. 2017. Southern elephant seals (Mirounga leonina Linn.) depredate toothfish longlines in the midnight zone. PLoS ONE, 12/2: 1-13. Accessed March 10, 2020 at https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172396.

Hofmeyr, G. 2015. "Southern Elephant Seal" (On-line). IUCN Redlist. Accessed March 03, 2020 at https://www.iucnredlist.org/species/13583/45227247.

Oceana, 2019. "Southern Elephant Seal" (On-line). Oceana. Accessed March 10, 2020 at https://oceana.org/marine-life/marine-mammals/southern-elephant-seal.

Reisinger, R., P. Bruyn, C. Tosh, W. Oosthuizen, N. Mufanadzo, M. Bester. 2011. Prey and seasonal abundance of killer whales at sub-Antarctic Marion Island. African Journal of Marine Science, Volume 33/ Issue 1: 99-105. Accessed March 10, 2020 at https://www.tandfonline.com/doi/abs/10.2989/1814232x.2011.572356.

Rodhouse, P., T. Arnbom, M. Fedak, J. Yeatman, W. Murray. 1992. "Cephalopod Prey of the Southern Elephant Seal, Mirounga leonina L." (On-line pdf). Accessed March 03, 2020 at https://www.nrcresearchpress.com/doi/pdf/10.1139/z92-143.