Southern Sea Lion
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The South American sea lion (''Otaria flavescens'', formerly ''Otaria byronia''), also called the southern sea lion and the Patagonian sea lion, is a
sea lion Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk on all fours, short and thick hair, and a big chest and belly. Together with the fur seals, they make up the family Otariidae, eared seals. ...
found on the western and southeastern coasts of
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
. It is the only member of the genus ''Otaria''. The species is highly
sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
. Males have a large head and prominent mane. They mainly feed on fish and
cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s and
haul out Hauling out is a behaviour associated with pinnipeds ( true seals, sea lions, fur seals and walruses) temporarily leaving the water. Hauling-out typically occurs between periods of foraging activity. Rather than remain in the water, pinniped ...
on sand,
gravel Gravel () is a loose aggregation of rock fragments. Gravel occurs naturally on Earth as a result of sedimentation, sedimentary and erosion, erosive geological processes; it is also produced in large quantities commercially as crushed stone. Gr ...
, rocky, or
pebble A pebble is a clastic rocks, clast of rock (geology), rock with a grain size, particle size of based on the Particle size (grain size), Udden-Wentworth scale of sedimentology. Pebbles are generally considered larger than Granule (geology), gra ...
beaches. In most populations, breeding males are both
territorial A territory is an area of land, sea, or space, belonging or connected to a particular country, person, or animal. In international politics, a territory is usually a geographic area which has not been granted the powers of self-government, ...
and
harem A harem is a domestic space that is reserved for the women of the house in a Muslim family. A harem may house a man's wife or wives, their pre-pubescent male children, unmarried daughters, female domestic Domestic worker, servants, and other un ...
holding; they establish territories first and then try to herd females into them. The overall population of the species is considered stable, estimated at 265,000 animals.


Naming

The South American sea lion was classified as ''Otaria flavescens'' by George Shaw in 1800 and as ''Otaria byronia'' by
Henri Marie Ducrotay de Blainville Henri Marie Ducrotay de Blainville (; 12 September 1777 – 1 May 1850) was a French zoologist and anatomist. Life Blainville was born at Arques-la-Bataille, Arques, near Dieppe, Seine-Maritime, Dieppe. As a young man, he went to Paris to study a ...
in 1820. The two nomenclatures were historically used interchangeably, but ''O. flavescens'' has become the preferred name. The species is also known by the common name "southern sea lion", although it is not preferred since the
Australian sea lion The Australian sea lion (''Neophoca cinerea''), also known as the Australian sea-lion or Australian sealion, is a species of sea lion that is the only endemic pinniped in Australia. It is currently Monotypic taxon, monotypic in the genus ''Neopho ...
and
New Zealand sea lion The New Zealand sea lion (''Phocarctos hookeri''), once known as Hooker's sea lion, and as (for both male and female) or (male) and (female) in Māori, is a species of sea lion that is endemic to New Zealand and primarily breeds on New Zeala ...
also range in the Southern Hemisphere. Locally, it is known by several names, including ''león marino'' (sea lion) and ''lobo marino'' (sea wolf).


Description

The South American sea lion is among the largest of and most
sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
of the eared seals. Males measure up to in length with a weight of while females reach a length and reach in weight. Pups are born long and weigh . Size differences between the sexes exists in both newborns and juveniles. Adult males have large heads with short, upturned snouts and long manes which reach the shoulders. The
fur A fur is a soft, thick growth of hair that covers the skin of almost all mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an ...
is mainly brownish with adult males being dark brown and females being nearly yellowish. Pups are born black but become reddish-brown after their first
molt In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is a process by which an animal casts off parts of its body to serve some beneficial purpose, either at ...
.


Ecology

The South American sea lion is found along the coasts and offshore islands of South America, from Peru south to
Cape Horn Cape Horn (, ) is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island. Although not the most southerly point of South America (which is Águila Islet), Cape Horn marks the nor ...
and then north to southern Brazil. Notable breeding colonies include
Lobos Island Lobos (, ) is a small island of the Canary Islands (Spain) located just north of the island of Fuerteventura. It belongs to the municipality of La Oliva on the island of Fuerteventura. It has an area of . It has been a nature reserve (''Parque ...
, Uruguay; Peninsula Valdes, Argentina;
Beagle Channel Beagle Channel (; Yahgan language, Yahgan: ''Onašaga'') is a strait in the Tierra del Fuego, Tierra del Fuego Archipelago, on the extreme southern tip of South America between Chile and Argentina. The channel separates the larger main island of I ...
, and the
Falkland Islands The Falkland Islands (; ), commonly referred to as The Falklands, is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and from Cape Dub ...
. Some individuals wander as far north as southern
Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...
, although apparently they never bred there. However, the movement ecology of South American sea lions remains poorly understood, although
biologging Biologging is the use of tags attached to animals to record aspects of their behaviour, physiology or environment. Description Often this can just be the location of the animal, e.g. GPS animal tracking GPS animal tracking is a process whe ...
studies in recent years have advanced our understanding of their at-sea movements at some breeding locations. There is no evidence of a winter migration of sea lions from the Falkland Islands. South American sea lions breed on
beach A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from Rock (geology), rock, such as sand, gravel, shingle beach, shingle, pebbles, etc., or biological s ...
es made of sand,
gravel Gravel () is a loose aggregation of rock fragments. Gravel occurs naturally on Earth as a result of sedimentation, sedimentary and erosion, erosive geological processes; it is also produced in large quantities commercially as crushed stone. Gr ...
, rocks, or
pebble A pebble is a clastic rocks, clast of rock (geology), rock with a grain size, particle size of based on the Particle size (grain size), Udden-Wentworth scale of sedimentology. Pebbles are generally considered larger than Granule (geology), gra ...
s. They can also be seen on flat, rocky cliffs with tidepools. Sea lion colonies tend to be small and scattered, especially on rocky beaches. The colonies make spaces between each individual when the weather is warm and sunny. South American sea lions consume numerous species of
fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
es, including
Argentine hake The Argentine hake (''Merluccius hubbsi'') is a merluccid hake of the genus '' Merluccius'', found in the southwestern Atlantic Ocean, along the coast of Argentina, and Uruguay. This fish was described by an Argentine ichthyologist, Tomás Mar ...
and
anchovies An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 1 ...
. They also eat
cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s, such as shortfin squid, Patagonian squid, and
octopus An octopus (: octopuses or octopodes) is a soft-bodied, eight-limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like oth ...
. They have even been observed preying on
penguin Penguins are a group of aquatic flightless birds from the family Spheniscidae () of the order Sphenisciformes (). They live almost exclusively in the Southern Hemisphere. Only one species, the Galápagos penguin, is equatorial, with a sm ...
s,
pelican Pelicans (genus ''Pelecanus'') are a genus of large water birds that make up the family Pelecanidae. They are characterized by a long beak and a large throat pouch used for catching prey and draining water from the scooped-up contents before ...
s, and young
South American fur seal The South American fur seal (''Arctocephalus australis'') breeds on the coasts of Peru, Chile, the Falkland Islands, Argentina, Uruguay and Brazil. The total population is around 250,000. However, population counts are sparse and outdated. Althou ...
s. South American sea lions may forage at the ocean floor for slow-moving prey or hunt schooling prey in groups, depending on the area. When captured, the
prey Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not ki ...
is shaken violently and torn apart. South American sea lions have been recorded to take advantage of the hunting efforts of
dusky dolphin The dusky dolphin (''Lagenorhynchus obscurus'') is a small oceanic dolphin found in coastal waters of the Southern Hemisphere. It is most closely related to the Pacific white-sided dolphin. The dolphin's range is patchy, major populations occ ...
s. The sea lions themselves are preyed on by
orca The orca (''Orcinus orca''), or killer whale, is a toothed whale and the largest member of the oceanic dolphin family. The only extant species in the genus '' Orcinus'', it is recognizable by its black-and-white-patterned body. A cosmopol ...
s and
shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...
s; at Peninsula Valdes, orcas will beach themselves and grab sea lions near shore.


Life history

Mating occurs between December and February. Males arrive first to establish and defend
territories A territory is an area of land, sea, or space, belonging or connected to a particular country, person, or animal. In international politics, a territory is usually a geographic area which has not been granted the powers of self-government, ...
, but then switch to defending females when they arrive. Estrus in females usually begins 6 days after the birth of a pup and soon after the copulations start with a peak in January. A male aggressively herds females in his territory and defends from both neighbors and intruders. On rocky beaches, males establish territories where females go to cool off, keeping them until
estrous The estrous cycle (, originally ) is a set of recurring physiological changes induced by reproductive hormones in females of mammalian subclass Theria. Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases ...
. On cobble or sandy beaches, males have territories near the surf and monopolize females trying to get access to the sea. The number of actual fights between males depends on the number of females in heat. The earlier a male arrives at the site, the longer his tenure will be and the more copulations he will achieve. Males are usually able to keep around three females in their
harems A harem is a domestic space that is reserved for the women of the house in a Muslim family. A harem may house a man's wife or wives, their pre-pubescent male children, unmarried daughters, female domestic Domestic worker, servants, and other un ...
, but some have as many as 18. During the breeding season, males that fail to secure territories and harems, most often subadults, will cause group raids in an attempt to change the ''status quo'' and gain access to the females. Group raids are more common on sandy beaches than rocky ones. These raids cause chaos in the breeding harems, often splitting mothers from their young. The resident males try to fight off the raiders and keep all the females in their territorial boundaries. Raiders are often unsuccessful in securing a female, but some are able to capture some females or even stay in the breeding area with one or more females. Sometimes, an invading male abducts pups, possibly as an attempt to control the females. They also take pups as substitutes for mature females. Subadults herd their captured pups and prevent them from escaping, much like adult males do to females. A pup may be mounted by its abductor, but intromission does not occur. While abducting pups does not give males immediate reproductive benefits, these males may gain experience in controlling females. Pups are sometimes severely injured or killed during abductions. Despite being mostly a harem-territorial species, one population in Peru has been recorded having a lek-like breeding system. Here, with its longer ratio of males in comparison to females, the males cluster together and display and try to attract females while allowing them to move freely. The warmer climate also makes the females move constantly to the water, further making the traditional mating system difficult to maintain. The group raids that exist in temperate populations are virtually non-existent here. Sea lion mothers remain with their newborn pups for nearly a week before making a routine of taking three-day foraging trips and coming back to nurse the pups. They act aggressively to other females that come close to their pups, as well as alien pups that try to get milk from them. Pups first enter the water at about four weeks and are weaned at about 12 months. This is normally when the mother gives birth to a new pup. Pups gradually spend more time in the nearshore surf and develop swimming skills. South American sea lions are observed to make various vocalizations and calls which differ between sexes and ages. Adult males make high-pitched calls during aggressive interactions, barks and growls when establishing territories, growls when interacting with females, and exhalations after antagonistic encounters. Females with pups make a mother primary call when interacting with their pups, and grunts during aggressive encounters with other females. Pups make pup primary calls. Some of those vocalizations and acoustic features may support individuality.


Human interactions

The Moche people of ancient
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
worshipped the sea and its animals. They often depicted South American sea lions in their art. Two statues of this species are the symbol of the city of
Mar del Plata Mar del Plata is a city on the coast of the Argentine Sea, Atlantic Ocean, in Buenos Aires Province, Argentina. It is the seat of General Pueyrredón Partido, General Pueyrredón district. Mar del Plata is the second largest city in Buenos Aires ...
. Indigenous peoples of South America exploited this species for millennia and by Europeans around the 16th century. The hunting has since gone down and the species is no longer threatened. The species is protected in most of its range. Numerous reserves and protected areas at rookeries and haul-out sites exist for the sea lions. Despite this, protection regulations are not effectively enforced in much of animals' range. The overall population of sea lions is considered stable; the estimate is 265,000 animals. They are declining in the Falkland Islands, and in Argentina
Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...
, but are increasing in Chile and Uruguay. Many sea lions of the Peruvian population died in the 1997/1998
el Niño EL, El or el may refer to: Arts and entertainment Fictional entities * El, a character from the manga series ''Shugo Chara!'' by Peach-Pit * Eleven (''Stranger Things'') (El), a fictional character in the TV series ''Stranger Things'' * El, fami ...
. They still are killed due to their habits of stealing fish and damaging fishing nets.


See also

*
Unihemispheric slow-wave sleep Unihemispheric slow-wave sleep (USWS) is sleep where one half of the brain rests while the other half remains alert. This is in contrast to normal sleep where both eyes are shut and both halves of the brain show unconsciousness. In USWS, also kno ...
* Pincoy – a sea-spirit in Chilote mythology that resembles a sea lion


References

{{Taxonbar, from=Q333649 Mammals described in 1800 Otariinae Fauna of Temperate South America Western South American coastal fauna Pinnipeds of South America Carnivorans of Brazil Taxa named by George Shaw Taxobox binomials not recognized by IUCN