Sea lion

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Sea lion
Temporal range: Late Oligocene – Holocene
California sea lion in La Jolla (70568).jpg
California sea lion (Zalophus californianus)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Clade: Pinnipedia
Family: Otariidae
Subfamily: Otariinae
Gray 1825
Genera

Eumetopias
Neophoca
Otaria
Phocarctos
Zalophus

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. The sea lions have six extant and one extinct species (the Japanese sea lion) in five genera. Their range extends from the subarctic to tropical waters of the global ocean in both the Northern and Southern Hemispheres, with the notable exception of the northern Atlantic Ocean. [1] They have an average lifespan of 20–30 years. [2] A male California sea lion weighs on average about 300 kg (660 lb) and is about 2.4 m (8 ft) long, while the female sea lion weighs 100 kg (220 lb) and is 1.8 m (6 ft) long. The largest sea lions are Steller's sea lions, which can weigh 1,000 kg (2,200 lb) and grow to a length of 3.0 m (10 ft). Sea lions consume large quantities of food at a time and are known to eat about 5–8% of their body weight (about 6.8–15.9 kg (15–35 lb)) at a single feeding. Sea lions can move around 16 knots (30 km/h; 18 mph) in water and at their fastest they can reach a speed of about 30 knots (56 km/h; 35 mph). [3] Three species, the Australian sea lion, the Galápagos sea lion and the New Zealand sea lion, are listed as endangered. [4] [5] [6]

Contents

Taxonomy

Steller sea lions haul out on a rock off the coast of Raspberry Island (Alaska). Alaska 2007 056.jpg
Steller sea lions haul out on a rock off the coast of Raspberry Island (Alaska).

Sea lions are related to walruses and seals. Together with the fur seals, they constitute the family Otariidae, collectively known as eared seals. Until recently, sea lions were grouped under a single subfamily called Otariinae, whereas fur seals were grouped in the subfamily Arcocephalinae. This division was based on the most prominent common feature shared by the fur seals and absent in the sea lions, namely the dense underfur characteristic of the former. Recent genetic evidence, suggests Callorhinus, the genus of the northern fur seal, is more closely related to some sea lion species than to the other fur seal genus, Arctocephalus. [7] Therefore, the fur seal/sea lion subfamily distinction has been eliminated from many taxonomies.

Nonetheless, all fur seals have certain features in common: the fur, generally smaller sizes, farther and longer foraging trips, smaller and more abundant prey items, and greater sexual dimorphism. All sea lions have certain features in common, in particular their coarse, short fur, greater bulk, and larger prey than fur seals. For these reasons, the distinction remains useful. The family Otariidae (Order Carnivora) contains the 15 extant species of fur seals and sea lions. Traditional classification of the family into the subfamilies Arctocephalinae (fur seals) and Otariinae (sea lions) is not supported, with the fur seal Callorhinus ursinus having a basal relationship relative to the rest of the family. [8] This is consistent with the fossil record which suggests that this genus diverged from the line leading to the remaining fur seals and sea lions about 6 million years ago (mya). Similar genetic divergences between the sea lion clades as well as between the major Arctocephalus fur seal clades, suggest that these groups underwent periods of rapid radiation at about the time they diverged from each other. The phylogenetic relationships within the family and the genetic distances among some taxa highlight inconsistencies in the current taxonomic classification of the family. [8]

Arctocephalus is characterized by ancestral character states such as dense underfur and the presence of double rooted cheek teeth and is thus thought to represent the most "primitive" line. It was from this basal line that both the sea lions and the remaining fur seal genus, Callorhinus, are thought to have diverged. The fossil record from the western coast of North America presents evidence for the divergence of Callorhinus about 6 mya, whereas fossils in both California and Japan suggest that sea lions did not diverge until years later. [8]

Physiology

Diving adaptations

Sea lion heart. Sea lion heart.jpg
Sea lion heart.

There are many components that make up sea lion physiology and these processes control aspects of their behavior. Physiology dictates thermoregulation, osmoregulation, reproduction, metabolic rate, and many other aspects of sea lion ecology including but not limited to their ability to dive to great depths. The sea lions' bodies control heart rate, gas exchange, digestion rate, and blood flow to allow individuals to dive for a long period of time and prevent side effects of high pressure at depth.

The high pressures associated with deep dives cause gases such as nitrogen to build up in tissues which are then released upon surfacing, possibly causing death. One of the ways sea lions deal with the extreme pressures is by limiting the amount of gas exchange that occurs when diving. The sea lion allows the alveoli to be compressed by the increasing water pressure thus forcing the surface air into cartilage lined airway just before the gas exchange surface. [9] This process prevents any further oxygen exchange to the blood for muscles, requiring all muscles to be loaded with enough oxygen to last the duration of the dive. However, this shunt reduces the amount of compressed gases from entering tissues therefore reducing the risk of decompression sickness. [9] The collapse of alveoli does not allow for any oxygen storage in the lungs, however. This means that sea lions must mitigate oxygen use in order to extend their dives. Oxygen availability is prolonged by the physiological control of heart rate in sea lions. By reducing heart rate to well below surface rates, oxygen is saved by reducing gas exchange as well as reducing the energy required for a high heart rate. [10] Bradycardia is a control mechanism to allow a switch from pulmonary oxygen to oxygen stored in the muscles which is needed when the sea lions are diving to depth. [10] Another way sea lions mitigate the oxygen obtained at the surface in dives is to reduce digestion rate. Digestion requires metabolic activity and therefore energy and oxygen are consumed during this process; however, sea lions can limit digestion rate and decrease it by at least 54%. [11] This reduction in digestion results in a proportional reduction in oxygen use in the stomach and therefore a correlated oxygen supply for diving. Digestion rate in these sea lions increases back to normal rates immediately upon resurfacing. [11] Oxygen depletion limits dive duration, but carbon dioxide (CO2) build-up also plays a role in the dive capabilities of many marine mammals. After a sea lion returns from a long dive, CO2 is not expired as fast as oxygen is replenished in the blood, due to the unloading complications with CO2. However, having more than normal levels of CO2 in the blood does not seem to adversely affect dive behavior. [12] Compared to terrestrial mammals, sea lions have a higher tolerance to storing CO2 which is what normally tells mammals that they need to breathe. [12] This ability to ignore a response to CO2 is likely brought on by increased carotid bodies which are sensors for oxygen levels that let the animal know its available oxygen supply. [12] Yet, the sea lions cannot avoid the effects of gradual CO2 build-up which eventually causes the sea lions to spend more time at the surface after multiple repeated dives to allow for enough built up CO2 to be expired. [12]

Parasites and diseases

Galapagos sea lions (Zalophus wollebaeki) can be infected with Philophthalmus zalophi, an eye fluke. These infections have heavy impacts on the survival of juveniles. [13] The disease appears to be compounded by global warming. The number of infectious stages of different parasites species has a strong correlation with temperature change, therefore it is essential to consider the correlation between the increasing number of parasitic infections and climate changes. The Galapagos Islands go through seasonal changes in sea surface temperatures, which consist of high temperatures from the beginning of January through the month of May and lower temperatures throughout the rest of the year. Parasites surfaced in large numbers when the sea temperature was at its highest. Furthermore, data was collected by capturing sea lions in order to measure and determine their growth rates. Their growth rates were noted along with the citings of parasites which were found under the eyelid. The shocking results were that sea lions are affected by the parasites from the early ages of 3 weeks old up until the age of 4 to 8 months. [13] The parasites found in the eye fluke did serious damage to the eye. From the data collected, 21 of the 91 survived; with a total of 70 deaths in just a span of two years. [13] The parasites are attacking the pups at such young ages and causing the pups to not reach the age of reproduction. The death rates of the pups is surpassing the fertility rate by far. Since most pups are unable to reach the age of reproduction, the population is not growing fast enough to keep the species out of endangerment. Other parasites, like Anisakis and heartworm, can also infect sea lions.

Australian sea lions (Neophoca cinerea) are also being affected by more frequent parasitic infections. [14] The same method was used for the sea pups as on the Galapagos Islands, but in addition, the researchers in Australia took blood samples. The pups in Australia were being affected by hookworms, but they were also coming out in large numbers with warmer temperatures. [14] New Zealand sea lion pups (Phocarctos hookeri) were also affected in really early ages by hookworms (Uncinaria). The difference is that in New Zealand researchers took the necessary steps and began treatment. [15] The treatment seemed to be effective on the pups who have taken it. They found no traces of this infection afterwards. However, the percentage of pups who do have it is still relatively high at about 75%. [15] Those pups who were treated had much better growth rates than those who did not. Overall parasites and hookworms are killing off enough pups to place them in endangerment. Parasites affect sea pups in various areas of the world. Reproductive success reduces immensely, survival methods, changes in health and growth have also been affected.

Similarly, climate change has resulted in increased toxic algae blooms in the oceans. These toxins are ingested by sardines and other fish which are then eaten by the sea lions, causing neurological damage and diseases such as epilepsy. [16]

Gene expressions and diet

Gene expressions are being used more often to detect the physiological responses to nutrition, as well as other stressors. In a study done with four Steller sea lions (Eumetopias jubatus), three of the four sea lions underwent a 70-day trial which consisted of unrestricted food intake, acute nutritional stress, and chronic nutritional stress. Results showed that individuals under nutritional stress down-regulated some cellular processes within their immune response and oxidative stress. Nutritional stress was considered the most proximate cause of population decline in this species. [17] In New Zealand sea lions, north-to south gradients driven by temperature differences were shown to be key factors in the prey mix. [18] Adult California sea lions eat about 5% to 8% of their body weight per day (15–40 lb (6.8–18.1 kg)).[ citation needed ]

California sea lions feed mainly offshore in coastal areas. They eat a variety of prey—such as squid, anchovies, mackerel, rockfish, and sardines—found in upwelling areas. They also may take fish from commercial fishing gear, sport fishing lines, and fish passage facilities at dams and rivers. [19]

Geographic variation

Geographic variation for sea lions have been determined by the observations of skulls of several Otariidae species; a general change in size corresponds with a change in latitude and primary productivity. Skulls of Australian sea lions from Western Australia were generally smaller in length whereas the largest skulls are from cool temperate localities. Otariidae are in the process of species divergence, much of which may be driven by local factors, particularly latitude and resources. [20] Populations of a given species tend to be smaller in the tropics, increase in size with increasing latitude, and reach a maximum in sub-polar regions. In a cool climate and cold waters there should be a selective advantage in the relative reduction of body surface area resulting from increased size, since the metabolic rate is related more closely to body surface area than to body weight. [20]

Breeding and population

Breeding methods and habits

Two sea lions on the beach of Otago Peninsula, New Zealand Two sea lions on the beach of Otago Peninsula.jpg
Two sea lions on the beach of Otago Peninsula, New Zealand

Sea lions, with three groups of pinnipeds, have multiple breeding methods and habits over their families but they remain relatively universal. Otariids, or eared sea lions, raise their young, mate, and rest in more earthly land or ice habitats. Their abundance and haul-out behavior have a direct effect on their on land breeding activity. Their seasonal abundance trend correlates with their breeding period between the austral summer of January to March. Their rookeries populate with newborn pups as well as male and female otariids that remain to defend their territories. At the end of the breeding period males disseminate for food and rest while females remain for nurturing. Other points in the year consist of a mix of ages and genders in the rookeries with haul-out patterns varying monthly. [21]

Steller sea lions, living an average of 15 to 20 years, begin their breeding season when adult males establish territories along the rookeries in early May. Male sea lions reach sexual maturity from ages 5 to 7 and do not become territorial until around 9 to 13 years of age. The females arrive in late May bringing in an increase of territorial defense through fighting and boundary displays. After a week births consist most usually of one pup with a perinatal period of 3 to 13 days.

Steller sea lions have exhibited multiple competitive strategies for reproductive success. Sea lion mating is often polygamous as males usually mate with different females to increase fitness and success, leaving some males to not find a mate at all. Polygamous males rarely provide parental care towards the pup. Strategies used to monopolize females include the resource-defense polygyny, or occupying important female resources. This involves occupying and defending a territory with resources or features attractive to females during sexually receptive periods. Some of these factors may include pupping habitat and access to water. Other techniques include potentially limiting access of other males to females. [22]

Population

Otaria flavescens (South American sea lion) lives along the Chilean coast with a population estimate of 165,000. According to the most recent surveys in northern and southern Chile the sealing period of the middle twentieth century that left a significant decline in sea lion population is recovering. The recovery is associated with less hunting, otariids rapid population growth, legislation on nature reserves, and new food resources. Haul-out patterns change the abundance of sea lions at particular times of the day, month, and year. Patterns in migration relate to temperature, solar radiation, and prey and water resources. Studies of South American sea lions and other otariids document maximum population on land during early afternoon, potentially due to haul-out during high air temperatures. Adult and subadult males do not show clear annual patterns, maximum abundance being found from October to January. Females and their pups hauled-out during austral winter months of June to September. [23]

Interactions with humans

Sea lions entertaining a crowd in Central Park Zoo. Sea lions entertaining crowd in Central Park Zoo, New York City 2.jpg
Sea lions entertaining a crowd in Central Park Zoo.

South American sea lions have been greatly impacted by human exploitation. During the late Holocene period to the middle of the twentieth century, hunter-gatherers along the Beagle Channel and northern Patagonia had greatly reduced the number of sea lions due to their hunting of the species and exploitation of the species' environment. [24] Although sealing has been put to a halt in many countries, such as Uruguay, the sea lion population continues to decline because of the drastic effects humans have on their ecosystems. [24] As a result, South American sea lions have been foraging at higher tropical latitudes than they did prior to human exploitation. [24] Fishermen play a key role in the endangerment of sea lions. Sea lions rely on fish, like pollock, as a food source and have to compete with fishermen for it. [25] When fishermen are successful at their job, they greatly reduce the sea lion's food source, which in turn endangers the species. [25] Also, human presence and human recreational activities can cause sea lions to engage in violent and aggressive actions. [26] When humans come closer than 15 meters of a sea lion, the sea lions' vigilance increases because of the disturbance of humans. [26] These disturbances can potentially cause sea lions to have psychological stress responses that cause the sea lions to retreat, sometimes even abandon their locations, and decreases the amount of time sea lions spend hauling out. [26]

Hundreds of California sea lions congregating at Pier 39, San Francisco Cal Sea Lions on Pier 39.JPG
Hundreds of California sea lions congregating at Pier 39, San Francisco

New Zealand sea lions were also exploited from hunting and sealing, and as a result were extirpated from New Zealand's mainland for over 150 years, with their population being restricted to the subantarctic. [27] In 1993, a female New Zealand sea lion gave birth on the mainland for the first time, and since then, they have slowly been recolonizing. [27] These sea lions are the only pinnipeds that regularly move up to 2 kilometres (1.2 mi) inland into forests. [28] [29] [30] As consequence, they have been hit by cars on roads, deliberately killed, and been disturbed by dogs. [31] Females need to move inland as a way to protect their pups, so roads, fences, residential areas, and private lands can inhibit their dispersal and breeding success. [32] They have also adapted to commercial pine forests, [32] and have given birth or nursed pups in residents' backyards and on golf courses. [33] As one of the world's rarest sea lions, and an endangered and endemic species, efforts are being made to facilitate coexistence between them and humans. [34] [35]

Sea lion attacks on humans are rare, but when humans come within approximately 2.5 meters (8 ft), it can be very unsafe. [26] In a highly unusual attack in 2007 in Western Australia, a sea lion leapt from the water and seriously mauled a 13-year-old girl surfing behind a speedboat. The sea lion appeared to be preparing for a second attack when the girl was rescued. An Australian marine biologist suggested that the sea lion may have viewed the girl "like a rag doll toy" to be played with. [36] [37] [38] In San Francisco, where an increasingly large population of California sea lions crowds docks along San Francisco Bay, incidents have been reported in recent years of swimmers being bitten on the legs by large, aggressive males, possibly as territorial acts. [39] [40] In April 2015, a sea lion attacked a 62-year-old man who was boating with his wife in San Diego. The attack left the man with a punctured bone. [41] In May 2017, a sea lion grabbed and pulled a girl into the water by her dress before retreating. The child was sitting on a pier side in British Columbia while tourists were illegally feeding the sea lions when the incident took place. [42] She was pulled out of the water with minor injuries and received antibiotic prophylactic treatment for seal finger infection from the superficial bite injury. [43] [44]

There have also been documented events of sea lions assisting humans. One such notable instance of this is when Kevin Hines jumped off the Golden Gate Bridge in a suicide attempt and was helped to stay afloat by a sea lion until he was rescued by the Coast Guard. [45]

Sea lions have also been a focus of tourism in Australia and New Zealand. [26] One of the main sites to view sea lions is in the Carnac Island Nature Reserve near Perth in Western Australia. This tourist site receives over 100,000 visitors, many of whom are recreational boaters and tourists, who can watch the male sea lions haul out on to the shore. [26] They have sometimes been called "the unofficial welcoming committee of the Galápagos Islands". [46]

Zalophus californianus at Moss Landing 3.jpg GiGi sea lion 1984.jpg Sea lion head.jpg Sea Lion Lounging.JPG
A gathering of more than 40 sea lions off the coast of CaliforniaA military sea lion on board a U.S. Navy shipA sea lion at the Memphis Zoo A sea lion pup sleeping at Pantai Inn
Sea lion head by the ocean.jpg Sealion052006.JPG Sea lion chillin'.jpg Sea lions chillin'.jpg
A sea lion in Malibu, CaliforniaSea Lion at Monterey BreakwaterA sea lion sleeps in the Ballestas Islands, PeruA group of sea lions rest in the Ballestas Islands, Peru

See also

Related Research Articles

<span class="mw-page-title-main">Earless seal</span> Family of mammals

The earless seals, phocids, or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae. They are sometimes called crawling seals to distinguish them from the fur seals and sea lions of the family Otariidae. Seals live in the oceans of both hemispheres and, with the exception of the more tropical monk seals, are mostly confined to polar, subpolar, and temperate climates. The Baikal seal is the only species of exclusively freshwater seal.

<span class="mw-page-title-main">Fur seal</span> Subfamily of mammals

Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family Otariidae. They are much more closely related to sea lions than true seals, and share with them external ears (pinnae), relatively long and muscular foreflippers, and the ability to walk on all fours. They are marked by their dense underfur, which made them a long-time object of commercial hunting. Eight species belong to the genus Arctocephalus and are found primarily in the Southern Hemisphere, while a ninth species also sometimes called fur seal, the Northern fur seal, belongs to a different genus and inhabits the North Pacific. The fur seals in Arctocephalus are more closely related to sea lions than they are to the Northern fur seal, but all three groups are more closely related to each other than they are to true seals.

<span class="mw-page-title-main">Eared seal</span> Marine mammals in the family Otariidae

An eared seal, otariid, or otary is any member of the marine mammal family Otariidae, one of three groupings of pinnipeds. They comprise 15 extant species in seven genera and are commonly known either as sea lions or fur seals, distinct from true seals (phocids) and the walrus (odobenids). Otariids are adapted to a semiaquatic lifestyle, feeding and migrating in the water, but breeding and resting on land or ice. They reside in subpolar, temperate, and equatorial waters throughout the Pacific and Southern Oceans, the southern Indian, and Atlantic Oceans. They are conspicuously absent in the north Atlantic.

<span class="mw-page-title-main">California sea lion</span> Species of carnivore

The California sea lion is a coastal eared seal native to western North America. It is one of six species of sea lions. Its natural habitat ranges from southeast Alaska to central Mexico, including the Gulf of California. California sea lions are sexually dimorphic; males are larger than females, and have a thicker neck, and a protruding sagittal crest. They mainly haul-out on sandy or rocky beaches, but they also frequent manmade environments such as marinas and wharves. California sea lions feed on a number of species of fish and squid, and are preyed on by orcas and great white sharks.

<span class="mw-page-title-main">Pinniped</span> Infraorder of mammals

Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semi-aquatic, mostly marine mammals. They comprise the extant families Odobenidae, Otariidae, and Phocidae, with 34 extant species and more than 50 extinct species described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage. Pinnipeds belong to the suborder Caniformia of the order Carnivora; their closest living relatives are musteloids, having diverged about 50 million years ago.

<span class="mw-page-title-main">Steller sea lion</span> Species of carnivore

The Steller sea lion is a large, near-threatened species of sea lion, predominantly found in the coastal marine habitats of the northeast Pacific Ocean and the Pacific Northwest regions of North America, from north-central California to Oregon, Washington and British Columbia to Alaska. Its range continues across the Northern Pacific and the Aleutian Islands, all the way to Kamchatka, Magadan Oblast, and the Sea of Okhotsk, south to Honshu's northern coastline. It is the sole member of the genus Eumetopias, and the largest of the so-called eared seals (Otariidae). Among pinnipeds, only the walrus and the two species of elephant seal are bigger. The species is named for the naturalist and explorer Georg Wilhelm Steller, who first described them in 1741. Steller's sea lions have attracted considerable attention in recent decades, both from scientists and the general public, due to significant declines in their numbers over an extensive portion of their northern range—notably in Alaska.

<span class="mw-page-title-main">Northern fur seal</span> Only fur seal in the northern hemisphere

The northern fur seal is an eared seal found along the north Pacific Ocean, the Bering Sea, and the Sea of Okhotsk. It is the largest member of the fur seal subfamily (Arctocephalinae) and the only living species in the genus Callorhinus. A single fossil species, Callorhinus gilmorei, is known from the Pliocene of Japan and western North America.

<span class="mw-page-title-main">Antarctic fur seal</span> Species of carnivore

The Antarctic fur seal is one of eight seals in the genus Arctocephalus, and one of nine fur seals in the subfamily Arctocephalinae. Despite what its name suggests, the Antarctic fur seal is mostly distributed in Subantarctic islands and its scientific name is thought to have come from the German vessel SMS Gazelle, which was the first to collect specimens of this species from Kerguelen Islands.

<i>Callorhinus</i> Genus of mammals

Callorhinus is a genus of sea lion. It contains the living northern fur seal (Callorhinus ursinus) as well as the extinct Callorhinus gilmorei and an unnamed species, both from the Pliocene and very beginning of the Pleistocene.

<span class="mw-page-title-main">Subantarctic fur seal</span> Species of carnivore

The subantarctic fur seal is a species of arctocephaline found in the southern parts of the Indian, Pacific, and Atlantic Oceans. It was first described by Gray in 1872 from a specimen recovered in northern Australia—hence the inappropriate specific name tropicalis.

<span class="mw-page-title-main">Guadalupe fur seal</span> Species of carnivore

The Guadalupe fur seal is one of eight members of the fur seal genus Arctocephalus. They are the northernmost member of this genus. Sealers reduced the population to just a few dozen by the late 19th century, but the species had recovered to 10,000 in number by the late 1990s. Many individuals can be found on Mexico's Guadalupe Island.

<span class="mw-page-title-main">Juan Fernández fur seal</span> Species of carnivore

The Juan Fernández fur seal is the second smallest of the fur seals, second only to the Galápagos fur seal. They are found only on the Pacific Coast of South America, more specifically on the Juan Fernández Islands and the Desventuradas Islands. There is still much that is unknown about this species. Scientists still do not know the average life span of this species, or the diet and behavior of males apart from the breeding season.

<span class="mw-page-title-main">Galápagos fur seal</span> Species of carnivore

The Galápagos fur seal is one of eight seals in the genus Arctocephalus and one of nine seals in the subfamily Arctocephalinae. It is the smallest of all of the eared seals. They are endemic to the Galápagos Islands in the eastern Pacific. The total estimated population as of 1970 was said to be about 30,000, although the population has been said to be on the decline since the 1980s due to environmental factors such as pollution, disease, invasive species, and their limited territory. Due to the population having been historically vulnerable to hunting, the Galápagos fur seal has been protected by the Ecuadorian government since 1934

<span class="mw-page-title-main">Australian sea lion</span> Species of carnivore

The Australian sea lion, 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 in the genus Neophoca, with the extinct Pleistocene New Zealand sea lion Neophoca palatina the only known congener. With a population estimated at 14,730 animals, the Wildlife Conservation Act of Western Australia (1950) has listed them as “in need of special protection”. Their Conservation status is listed as endangered. These pinnipeds are specifically known for their abnormal breeding cycles, which are varied between a 5-month breeding cycle and a 17-18 month aseasonal breeding cycle, compared to other pinnipeds which fit into a 12-month reproductive cycle. Females are either silver or fawn with a cream underbelly and males are dark brown with a yellow mane and are bigger than the females.

<i>Neophoca</i> Genus of carnivores

Neophoca is a genus of the family Otariidae of order Carnivora. It is combined by some taxonomists with the genus Phocarctos, the (extant) New Zealand sea lion. Only one species survives:

<span class="mw-page-title-main">New Zealand sea lion</span> Species of carnivore

The New Zealand sea lion, once known as Hooker's sea lion, and as pakake or whakahao (male) and kake (female) in Māori, is a species of sea lion that is endemic to New Zealand and primarily breeds on New Zealand's subantarctic Auckland and Campbell islands, and have in recent years been slowly breeding and recolonising around the coast of New Zealand's South and Stewart islands. The New Zealand sea lion numbers around 12,000 and is one of the world's rarest sea lion species. They are the only species of the genus Phocarctos.

<i>Arctocephalus forsteri</i> Species of carnivore

Arctocephalus forsteri is a species of fur seal found mainly around southern Australia and New Zealand. The name New Zealand fur seal is used by English speakers in New Zealand; kekeno is used in the Māori language. As of 2014, the common name long-nosed fur seal has been proposed for the population of seals inhabiting Australia.

<span class="mw-page-title-main">Galápagos sea lion</span> Species of carnivore

The Galápagos sea lion is a species of sea lion that lives and breeds on the Galápagos Islands and, in smaller numbers, on Isla de la Plata (Ecuador). Being fairly social, they are often spotted sun-bathing on sandy shores or rock groups, or gliding through the surf. They are the smallest sea lion species.

References

  1. ↑ "California Sea Lion – SeaWorld Info Book". SeaWorld. Archived from the original on 14 April 2015. Retrieved 26 December 2013.
  2. ↑ "California sea lion". Smithsonian's National Zoo. 25 April 2016. Retrieved 24 September 2023.
  3. ↑ Riedman, Marianne (13 December 1989). The Pinnipeds: Seals, Sea lions, and Walruses . University of California Press. p.  7. ISBN   9780520064973.
  4. ↑ Chilvers, B. L. (2015). "Phocarctos hookeri. The IUCN Red List of Threatened Species". International Union for Conservation of Nature and Natural Resources. doi: 10.2305/IUCN.UK.2015-2.RLTS.T17026A1306343.en .
  5. ↑ Trillmich, F. (2015). "Arctocephalus galapagoensis. The IUCN Red List of Threatened Species". International Union for Conservation of Nature and Natural Resources. doi: 10.2305/IUCN.UK.2015-2.RLTS.T2057A45223722.en .
  6. ↑ Goldsworthy, S. D. (2015). "Neophoca cinerea. The IUCN Red List of Threatened Species". International Union for Conservation of Nature and Natural Resources. doi: 10.2305/IUCN.UK.2015-2.RLTS.T14549A45228341.en .
  7. ↑ Wynen, L.P.; Goldsworthy, SD; Insley, SJ; Adams, M; Bickham, JW; Francis, J; Gallo, JP; Hoelzel, AR; et al. (2001). "Phylogenetic relationships within the eared seals (Otariidae: Carnivora): implications for the historical biogeography of the family". Mol. Phylogenet. Evol. 21 (2): 270–284. doi:10.1006/mpev.2001.1012. PMID   11697921.
  8. 1 2 3 Wynen, Louise P.; Goldsworthy, Simon D.; Insley, Stephen J.; Adams, Mark; Bickham, John W.; Francis, John; Gallo, Juan Pablo; Hoelzel, A. Rus; Majluf, Patricia (1 November 2001). "Phylogenetic Relationships within the Eared Seals (Otariidae: Carnivora): Implications for the Historical Biogeography of the Family". Molecular Phylogenetics and Evolution. 21 (2): 270–284. doi:10.1006/mpev.2001.1012. PMID   11697921.
  9. 1 2 Kooyman, G. L.; Sinnett, E. E. (1 January 1982). "Pulmonary Shunts in Harbor Seals and Sea Lions during Simulated Dives to Depth". Physiological Zoology. 55 (1): 105–111. doi:10.1086/physzool.55.1.30158447. JSTOR   30158447. S2CID   87390381.
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  18. ↑ Roberts, J.; Lalas, C. (June 2015). "Diet of New Zealand sea lions (Phocarctos hookeri) at their southern breeding limits". Polar Biology. 38 (9): 1483–1491. doi:10.1007/s00300-015-1710-3. S2CID   7836909.
  19. ↑ "California Sea Lion". NOAA . Retrieved 6 January 2024.
  20. 1 2 Brunner, S.; Shaughnessy, P. D.; Bryden, M. M. (2002). "Geographic variation in skull characters of fur seals and sea lions (family Otariidae)". Australian Journal of Zoology. 50 (4): 415. doi:10.1071/ZO01056.
  21. ↑ Sepúlveda, Maritza (August 2015). "Annual, seasonal and daily variation in the abundance of the South American sea lion Otaria flavescens in two breeding colonies in northern Chile" (PDF). Revista de Biologia Marina y Oceanografia. 50 (2): 205–220. doi: 10.4067/S0718-19572015000300001 .
  22. ↑ Parker, Pamela; Maniscalco, John, M. (20 March 2014). "A long-term study reveals multiple reproductive behavior strategies among territorial adult male Steller sea lions (Eumetopias jubatus)". Canadian Journal of Zoology. 92 (5): 405–415. doi:10.1139/cjz-2013-0099.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  23. ↑ Sepulveda, Maritza (August 2015). "Annual, seasonal and daily variation in the abundance of the South American sea lion Otaria flavescens in two breeding colonies in northern Chile" (PDF). Revista de Biologia Marina y Oceanografia. 50 (2): 205–220. doi: 10.4067/S0718-19572015000300001 . Retrieved 29 October 2015.
  24. 1 2 3 Zenteno, Lisette; Borella, Florencia; Otero, Julieta Gómez; Piana, Ernesto; Belardi, Juan Bautista; Borrero, Luis Alberto; Saporiti, Fabiana; Cardona, Luis; Crespo, Enrique (1 June 2015). "Shifting niches of marine predators due to human exploitation: the diet of the South American sea lion (Otaria flavescens) since the late Holocene as a case study". Paleobiology. 41 (3): 387–401. doi:10.1017/pab.2015.9. ISSN   1938-5331. S2CID   86469393.
  25. 1 2 Gong, Min; Heal, Geoffrey (12 December 2013). "Why do People Care about Sea Lions? A Fishing Game to Study the Value of Endangered Species". Environmental and Resource Economics. 59 (4): 503–523. doi:10.1007/s10640-013-9746-8. ISSN   0924-6460. S2CID   154083833.
  26. 1 2 3 4 5 6 Jean-Paul, Orsini (1 January 2004). "Human impacts on Australian sea lions, Neophoca cinerea, hauled out on Carnac Island (Perth, Western Australia): implications for wildlife and tourism management". researchrepository.murdoch.edu.au. Retrieved 30 October 2015.
  27. 1 2 Childerhouse, Simon; Gales, Nick (1 January 1998). "Historical and modern distribution and abundance of the New Zealand sea lion Phocarctos hookeri" . New Zealand Journal of Zoology. 25 (1): 1–16. doi:10.1080/03014223.1998.9518131. ISSN   0301-4223.
  28. ↑ Augé, Amélie; Chilvers; Moore; Mathieu; Robertson (1 January 2009). "Aggregation and dispersion of female New Zealand sea lions at the Sandy Bay breeding colony, Auckland Islands: How unusual is their spatial behaviour?" . Behaviour. 146 (9): 1287–1311. doi:10.1163/15683909X427687. ISSN   0005-7959.
  29. ↑ Augé, Amélie A.; Chilvers, B. Louise; Mathieu, Renaud; Moore, Antoni B. (2012). "On-land habitat preferences of female New Zealand sea lions at Sandy Bay, Auckland Islands" . Marine Mammal Science. 28 (3): 620–637. doi:10.1111/j.1748-7692.2011.00515.x. ISSN   1748-7692.
  30. ↑ Frans, Veronica F.; Augé, Amélie A.; Edelhoff, Hendrik; Erasmi, Stefan; Balkenhol, Niko; Engler, Jan O. (2018). "Quantifying apart what belongs together: A multi-state species distribution modelling framework for species using distinct habitats". Methods in Ecology and Evolution. 9 (1): 98–108. doi: 10.1111/2041-210X.12847 . ISSN   2041-210X. S2CID   91050320.
  31. ↑ Roberts, Jim (2015). Review of threats to the recovery of NZ sea lions and other otariid species (PDF). Wellington: National Institute of Water & Atmospheric Research Ltd. pp. 11–14.
  32. 1 2 Frans, Veronica F.; Augé, Amélie A.; Fyfe, Jim; Zhang, Yuqian; McNally, Nathan; Edelhoff, Hendrik; Balkenhol, Niko; Engler, Jan O. (2022). "Integrated SDM database: Enhancing the relevance and utility of species distribution models in conservation management" (PDF). Methods in Ecology and Evolution. 13: 243–261. doi:10.1111/2041-210X.13736. ISSN   2041-210X. S2CID   243893898.
  33. ↑ "New Zealand city closes busy road for weeks to protect sea lion mother and pup". the Guardian. 14 January 2021. Retrieved 22 November 2021.
  34. ↑ Graham-McLay, Charlotte (9 November 2021). "New Zealand's Sea Lions Are Back, and Crashing Golf Courses and Soccer Matches". The New York Times. ISSN   0362-4331. Archived from the original on 28 December 2021. Retrieved 22 November 2021.
  35. ↑ "'Cheeky' sea lions are returning to New Zealand's shores — and locals are learning to share the coast". Washington Post. ISSN   0190-8286 . Retrieved 22 November 2021.
  36. ↑ Sea lion attacks Australian girl. BBC News (15 April 2007). Retrieved on 2016-05-09.
  37. ↑ Hayward, Andrea (15 April 2007) Monster sea lion likely to be 'playing' with teen. news.com.au
  38. ↑ Sea lion mauls girl. News.com.au (15 April 2007).
  39. ↑ Kay, Jane (24 June 2011). "Rogue sea lion in S.F. menaces swimmers / Marauding mammal bites at least 14, chases 10 from Aquatic Park Lagoon". The San Francisco Chronicle.
  40. ↑ Harrell, Ashley (7 October 2009). "Too Cute to Shoot? – Page 1 – News – San Francisco". SF Weekly. Archived from the original on 10 August 2015. Retrieved 28 June 2012.
  41. ↑ "Sea lion attacks San Diego man posing for photo, yanks him overboard". www.cbsnews.com. 30 April 2015.
  42. ↑ "Video shows the terrifying moment a sea lion yanks a girl into the water". Washington Post. Retrieved 22 May 2017.
  43. ↑ "Steveston Sea Lion Video: Girl Grabbed By Animal Treated For Superficial Wound". HuffPost Canada. 23 May 2017. Retrieved 20 September 2018.
  44. ↑ "Sea lion attack: Girl treated over 'seal finger' risk". BBC News. 26 May 2017. Retrieved 26 May 2017.
  45. ↑ Bergeron, Ryan (12 August 2019). "He jumped off the Golden Gate Bridge and survived. Now, he's seeing his wish for a safety net come true". CNN . Retrieved 17 August 2019.
  46. ↑ "In the Galapagos Islands they’re so ubiquitous that they run the risk of being taken for granted. Here, you can find this unofficial welcoming committee almost everywhere"

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