Australian sea lions are fully protected within Australia. They were listed as “rare” in the 1994 IUCN Red List of Threatened Animals. They have been recently removed from this list, and the population has remained stable at around 10,000 animals (World Conservation Monitoring Centre, 2000). Harvesting of this species is not allowed, and a permit is required for research or capture for zoos (Toorn, 1999).
CITES: no special status
IUCN Red List of Threatened Species: endangered
One of the predators of the Australian sea lion is the great white shark (Carcharodon carcharias), especially near the Dangerous Reef region of the Port Lincoln area (Riedman, 1990). Fishermen also occasionally kill them accidentally by entangling them in their nets (World Conservation Monitoring Centre, 2000). Historically, the population was greatly reduced due to sealing (Jefferson, 1993).
Known Predators:
At birth, pups are roughly 60 to 70 cm and weigh approximately 6.5 to 8 kg. Their pelage is initially chocolate brown, but is replaced by adult-like fawn colred fur by the age of two months. Australian sea lions are sexually dimorphism, with a significant difference in the size of females and of males. As an adult, males grow to about 2.5 m and weigh 300 kg. Females grow to a length of about 1.8 m and weigh approximately 105 kg. Females reach sexual maturity at around 3 years of age, whereas males usually do not mature until they are 6 years of age or older. Males darken even further as they mature, and go through a transition phase where they have spots on their chests.
Australian sea lions have a large head with a long, narrow, and tapered muzzle. The skull has a sagittal crest approximately 30 mm in height. Males display a much larger head than females and juveniles, as well as significantly broader shoulders. Their pinnae, or ears, are incredibly small and lie close to the head. Juveniles are a dark brown with a pale crown and a dark facial mask. Subadult males and females display a coat that is fawn to silvery-gray on top and tan to pale yellow on the bottom. Mature males are dark brown with a cream-colored crown and nape, and a paler chest and throat area.
Range mass: 105 to 300 kg.
Range length: 1.8 to 2.5 m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Information on longevity in this species is not available.
Range lifespan
Status: captivity: 24.1 (high) years.
Australian sea lions are non-migratory , so they live and breed on sandy beaches near their birth site in relatively large colonies. The greatest distance recorded for a tagged animal has been 300km from its birth site (Jefferson, 1993). During times of tumultuous weather, they will often travel inland to seek shelter in dunes and coastal vegetation (Riedman 1990). Unlike many pinnipeds, Australian sea lions are very capable out of the water, and have been found as far as 9.4 km inland (Nowak, 1999). Many have been found at the tops of cliffs as high as 30 meters, as they are also excellent climbers.
In the water, Neophoca cinerea has been seen at depths up to 40 meters (Nowak, 1999).
Range elevation: 30 (high) m.
Range depth: 40 (high) m.
Habitat Regions: temperate ; terrestrial ; saltwater or marine
Terrestrial Biomes: desert or dune
Aquatic Biomes: reef ; coastal
Australian sea lions are found on islands offshore of Australia. They range from western Australia to islands in southern Australia. The largest populations are found on Kangaroo Island and Dangerous Reef (near Port Lincoln) in southern Australia. The smallest numbers are found on the west coast of southern Australia and in Western Australia. Some live in Tasmania as well, but these are few in number. They once bred in the Bass Strait, but the entire population was wiped out by the sealing industry.
Biogeographic Regions: australian (Native ); indian ocean (Native ); pacific ocean (Native )
Australian sea lions feed on a small number of fishes (which include whiting, rays, and small sharks), squid, cuttlefish, and fairy penguins (Eudyptula minor). The main diet of N. cinerea consists of blue-throated wrasse (Notolabrus tetricus) and octopus (Achtel, P., personal communication). They concentrate on shallow-water benthic prey, and usually dive for food at depths no greater than 37 meters (Riedman, 1990).
Animal Foods: birds; fish; mollusks
Primary Diet: carnivore (Eats terrestrial vertebrates, Piscivore , Molluscivore )
This species is probably a component of control on fish and penguin populations.
The beauty and docility of Australian sea lions draws tens of thousands of tourists to Seal Bay on Kangaroo Island every year.
Positive Impacts: ecotourism
Fishermen often see them as a nuisance as they rob fishing nets and rock lobster traps.
See Reproduction.
Perception Channels: tactile ; chemical
In the past, there have been times of great fluctuation in the population numbers of Australian sea lions. The main reason suspected for the decrease in numbers was parasites such as hookworm. Other factors such as environmental disturbance, male aggression, human harassment, injuries from fishing gear, and competition for resources with the New Zealand fur seal, may all have played a part in their population decline (Goldie, 1998).
Other common names for Australian sea lions are hair seal, white-necked hair seal, white-capped hair seal, and counselor seal (Riedman, 1990).
The mating system of this sea lion is polygynous. A male secures a breeding territory on the beach and actively defends it against other males though ritualized posturing and aggressive confrontation. The male leaves his territory to feed in the ocean for a few hours at a time. Upon his return, he may have to battle to regain his territory.
Males keep several females on their territories. If the female strays, the male will aggressively herd her back, sometimes entering another male's territory to do so. (Nowak, 1999)
Males have been seen killing pups, although presumably not their own. Defense of territories may be an indirect mechanism of paternal care for young.
There is some evidence of cooperative breeding (See Behavior) in which females care for pups other than their own.
Mating System: polygynous ; cooperative breeder
Australian sea lions have a breeding cycle of approximately 17.6 months. These non-annual cycles are affected by some unknown factor, not by environmental influence as previously thought (Higgins, 1993). Some females do not produce young in consecutive breeding seasons (Nowak, 1999). Births can occur over a period of 4-6 months in any colony of N. cinerea, making births highly unsynchronized.
When the breeding cycle begins, males copulate with harems of four or five females at a time (Ridgway, 1972). Males also have the ability to herd the females into mating groups, a feature rare in other species of sea lion (Riedman, 1990).
Females enter estrous about 6 days after giving birth, and are mated by the male at this time. There is some debate in the literature about the ensuing gestation period. Pinnipeds typically experience a delay in implantation of about three months, followed by an eight or nine month placentation. Because N. cinerea experiences a much longer interbirth interval, it is clear that this species differs from the typical pinniped pattern. Some investigators think that Australian sea lions experience a longer than average dely in implantation of the blastocyst, amounting to 10-11 months, and a normal length pregnancy (8-9 months). Others think there is a more typical pinniped length delay in implantation (5-6 months) and a longer than average placentation (over 12 months). (Nowak, 1999)
Young are typically weaned just before the birth of subsequent offspring, at 15-18 months. However, females have been seen nursing pups of different ages at the same time.
Breeding season: Because the breeding interval is oddly spaced, the breeding season steadily shifts throughout the calendar year.
Average number of offspring: 1.
Range gestation period: 512 to 576 days.
Range weaning age: 15 to 18 months.
Range age at sexual or reproductive maturity (female): 3 to 6 years.
Range age at sexual or reproductive maturity (male): 3 to 6 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous ; delayed implantation
Average birth mass: 7075 g.
Average number of offspring: 1.
Female N. cinerea come to shore about two days before they give birth in order to establish a natal site. After giving birth to a pup, the female will stay at the natal site for approximately 10 days before returning to the sea to forage. She will return to land every couple of days to nurse her young, staying with the pup for about 33 hours at a time. A mother uses both vocal and scent communication to locate and identify her pup.
As pups grow up, they often form small groups and swim in shallow rock pools before they venture into the ocean with their mothers.
Females care for their own young, nursing them until about 26 days before giving birth to their next pup. Some mothers have been seen nursing both a yearling and a newborn pup. There are reports of females being aggressive to pups other than their own, but there are also some reports of females taking care of groups of pups. This makes it difficult to determine how much cooperative care of young there might actually be, although it is clear that some cooperative care occurs. Altricial at birth, pups are able to follow their mothers both on land and into the sea at approximately 3 months of age.
No specific male parental care has been reported for N. cinerea, but by maintaining territories, fathers may protect their offspring from other males of the species.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
Avstraliya dəniz şiri, və ya Ağpapaqlı dəniz şiri (lat. Neophoca cinerea) — Qulaqlı suiti fəsiləsinin aid, Avstraliyanın cənub və qərb sahillərində yayayan növ.
Bu növün erkəkləri 2,5 metr uzunluğa və 300 kq çəkiyə malik olurlar. Dişiləri isə 1,8 m uzunluğa və 100 kq çəkiyə malik olur. Bu növün fərdləri bir-birindən kəskin fərqlənir: Erkəklər tünd-qəhvəyi, dişilərdə isə üzəri gümüşü-boz və ya açıq qəhvəyi olur. Dişilərin aşağı hissələri nisbətən açıq rəngdə olur.
Bu növün koloniyalarına Avstraliyanın cənub və sərb sahillərində rast gəlinir. Bəzən onlar sahilə yaxın kiçik adalarda da yaşayırlar. XIX əsrdə onların yaşadığı areal Tasmaniya və Yeni Cənubi Uels ərazilərinidə təşkil edirdi. Avstraliya dəniz şiri heç vaxt bir yerdən başqa yerə miqrasiya etmir (hətta çütləşmə dönəmində). Onlara nadir hallarda sahildən 300 km aralıda müşahidə edilir.
Avstraliya dəniz şiri Qulaqlı suitilərin digər növləri kimi çütləşmə dönəmində özlərini başqa cür aparırlar. Erkəklər dişiyə sahiblənmək üçün ən yaxşı ərazi uğrunda bir-biri ilə buruşurlar. Ən zəif erkəklər koloniyanın uçqar ərazilərinə çəkilməli olurlar. Koloniyada daim sakitçilik höküm sürür. Cavan erkəklər qüçlü və qoçaman erkəklərin diqqətsizliyindən istifadə edərək dişilərə sahiblənməyə çalışırlar. Avstraliya dəniz şiri digər növlərə nisbətən daha aqrissiv olurlar (bu baxımından Cənub dəniz şirinidə ötürlər).
Avstraliya sahillərində yaşayan Kap dəniz pişiyi və Yeni Zelandiya dəniz pişiyi kimi suitilərinə nisbətdə Avstraliya dəniz şiri az rast gəlinən növdür. Onların ümumi sayı 12-min baş təşkil edir. Onların sayının əvvəlki dövrlərə nisbətən çox olmasına baxmayaraq yayılma arealı baxımından azalma müşahidə edilir.
Avstraliya dəniz şiri, və ya Ağpapaqlı dəniz şiri (lat. Neophoca cinerea) — Qulaqlı suiti fəsiləsinin aid, Avstraliyanın cənub və qərb sahillərində yayayan növ.
Morleon Aostralia (Neophoca cinerea) a zo ur bronneg mor eus ar c'herentiad Otariidae. Ar spesad nemetañ eo er genad Neophoca.
Tiriad morleon Aostralia El lleó marí australià (Neophoca cinerea) és una espècie d'otàrid gran que viu a les costes del sud-oest d'Austràlia. És l'única espècie vivent del gènere Neophoca.
Els mascles poden arribar a mesurar fins a 2,5 m de llarg i pesar fins a 300 kg, mentre que les femelles només assoleixen 1,8 m i 100 kg. Els dos gèneres també es diferencien en el color: els mascles són de color marró fosc, mentre que les femelles són de color argentat o marró clar i tenen el ventre més clar que el dors.
El lleó marí australià (Neophoca cinerea) és una espècie d'otàrid gran que viu a les costes del sud-oest d'Austràlia. És l'única espècie vivent del gènere Neophoca.
Els mascles poden arribar a mesurar fins a 2,5 m de llarg i pesar fins a 300 kg, mentre que les femelles només assoleixen 1,8 m i 100 kg. Els dos gèneres també es diferencien en el color: els mascles són de color marró fosc, mentre que les femelles són de color argentat o marró clar i tenen el ventre més clar que el dors.
Lachtan šedý (Neophoca cinerea) je endemický ploutvonožec obývající pobřeží Austrálie, jediný druh monotypického rodu Neophoca z čeledě lachtanovitých. Jako jediní z ploutvonožců mají nesynchronní reprodukční cyklus trvající průměrně 17,5 měsíce.
Páří se, rodí a vychovávají potomstvo na písečných, travnatých nebo skalnatých pobřežích okolo Západní Austrálie (asi 30 % populace) a Jižní Austrálie (asi 70 %). V 19. století se hojně vyskytovali ještě okolo břehů Victorie, Nového Jižního Walesu a Tasmánie, v současnosti jsou tam spatřeni jen vzácně. Své nepříliš rozsáhlé hnízdiště mívají na ostrůvcích jen málo vzdálených od pevniny nebo na pobřežních skaliskách. Pouze na pěti ze 73 známých hnízdišť se průměrně rodí více než stovka mláďat ročně, což představuje téměř 60 % všech narozených. Největší lokality se nacházejí u pobřeží Jižní Austrálii, jsou to: Dangerous Reef, The Pages Islands, West Waldegrave Island, Seal Bay na Kangaroo Island a Olive Island. Několik málo drobných kolonií se nachází přímo na pevnině. Preferují chráněné závětrné strany ostrovů a mělké pobřežní vody pro výuku plavání potomků. Největší kolonii na The Pages Islands tvoří asi 1650 jedinců a za sezonu je zde odchováno asi 160 mláďat. V malých koloniích bývá jen okolo 100 zvířat a rodí se tam do 30 mláďat.
Nevydávají se za potravou daleko, zdržují se převážně v kontinentálních šelfových vodách blízko své rodné kolonie na kterou se také vracejí k páření. Před bouřlivým počasím se někdy ukrývají v písečných dunách nebo ve vnitrozemí, byli spatřeni i ve vzdálenosti 9 km od pobřeží. Vylézají také na kamenité útesy až do výše 30 metrů. Jejich nejbližším příbuzným je lachtan novozélandský.[2][3][4][5][6]
Lachtani šedí mají poměrně velikou hlavu s dlouhou, zúženou a tupou tlamou, jejich ušní boltce jsou velmi malé a přiléhají k hlavě. Dospělí samci mají vrchol hlavy a šíjí tmavě hnědou až krémovou, hrudní a krční partie světlejší, jejich lebka je mohutnější a tělo celkově mohutnější. Samice a nedospělí samci jsou na svrchní straně těla žlutí až stříbřitě šedí, na spodní hnědí až světle žlutí. Sexuální dimorfismus se projevuje i ve velikost. Samci měří až 2,5 m a váží 300 kg, samice dorůstají do délky okolo 1,8 m a váhy 105 kg. Mají silné přední i zadní ploutve, dokáži je složit pod sebe a vztyčit se na nich, jsou na pevné zemi velmi pohybliví. Při plavání veslují předními a kormidlují zadními.
Potravu si hledají v pobřežních vodách, potápějí se převážně do hloubky 40 až 80 metrů na dobu 2 až 4 minuty. Zaregistrovaný nejhlubší ponor činil 105 metrů a nejdelší čas ponoru byl okolo 8 minut. Soustřeďují se na mělké vody kde lapají kořist u dna, bývají to hlavně ryby, hlavonožci, korýši, malí tučňáci i želvy. Větší kořist vynášejí na povrch kde ji roztrhávají na polykatelné sousta. Lovu věnují hodně času, loví v málo úživném teplém Leeuwinově proudu který hlavně v zimě obsahuje málo potravy. Samci se při lovu vzdalují od své kolonie do 200 km, samice během kojení mláďat loví ve vzdálenosti 20 až 30 km od pobřeží.[2][3][4][5][6]
Nejpozoruhodnější u samic lachtanů šedých je doba březosti trvající až 14 měsíců a situace, že samice nevrhnou mláďata v kolonií ve stejnou dobu (synchronně), ale v rozmezí 4 až 7 měsíců. Z toho vychází průměrná doba mezi jednotlivými vrhy kolonie 17,5 měsíců. Navíc doby porodů v každé kolonii neprobíhají ve stejných měsících jako v ostatních. Mláďata lachtana šedivého se tak rodí průběžně po celý rok, v letním i zimním období. Dosud není známo, jaká okolnost tento nepravidelný a neroční cyklus vyvolává.
Ani mezi blízkými hnízdišti neprobíhá výměna samic, jejich geny se navzájem mísí jen minimálně. Geny samců jsou rozptýleny v okruhu do 200 km. Vyšetřováním genetické struktury pomoci mitochondriální DNA se zjistilo, že populace v jednotlivých koloniích jsou genetický tak velice rozdílné, že to nemá u jiných mořských savců obdoby. Rozdělení samic do jednotlivých kolonií muselo nastat již v dávnověku a stále se striktně po další a další generace dodržuje. Mladiství i dospělí samci občas mezi blízkými koloniemi migrují.[4][7]
Samice připlouvají na břeh asi dva dny před porodem. Mláďata váží mezi 6,4 až 7,9 kg a jsou velká 62 až 68 cm. Samice asi po 10 dnech přerušuje kojení na dva a postupně více dnů a odcházívá do moře za potravou, u mláděte většinou zůstává starší "sestra". O mládě se samice stará až 18 měsíců a obvykle jej odstaví až při příštím vrhu. Pokud samice nezabřezne, kojí mládě i 40 měsíců. Někdy kojí současně potomka čerstvě narozeného i toho z minulého vrhu. Jsou známy případy, že při uhynutí samice se o mládě starala cizí.
Samice jsou schopné páření asi za týden po porodu, na což netrpělivě čekají samci bránicí své stádo 4 až 5 samic hlasitými hrdelními zvuky a výhrůžnými gesty a pohyby. Tyto zápasy podstupují vždy po návratu z krmení v moři, kdy si znovu musí vybojovat "své" samice a území. Při těchto zápasech, stejně jako při páření, je mnoho mláďat pošlapáno. Některé samice mívají mladé ob jeden rok, samci o potomstvo nejeví pražádný zájem. V prvých dvou létech se odhaduje úmrtnost zvířat na 40 až 80 %. Samice mají prvá mláďata průměrně ve 4,5 létech, samec se může pářit v 6 létech. Průměrně se dožívají 11 let.[2][3][4][5]
V současnosti se odhaduje počet lachtanů šedých na 11 200 jedinců. Jsou australskými zákony považováni za vzácné a jsou zvláště chráněni. Jejich počet v 18. a 19. století následkem lovu značně poklesl a doposud se přes všechna opatření nezvýšil, je stále zhruba na stejné výši.
Druh je potenciálně ohrožen neschopnosti samic při zániku "domácí" kolonie zařadit se do kterékoliv jiné. Nepříznivou okolností je také dlouhá doba od početí do porodu výrazně zpomalující rozšiřování druhu. Z přirozených nepřátel je nejnebezpečnější žralok bílý. Největším zlem jsou pro ně ale rybáři, do jejíž sítí se často chytnou a udusí. Rybářům často vybírají ze sítí ulovené ryby nebo humry i políčené nástrahy na větší ryby.
Podle IUCN jsou lachtani šedí hodnoceni jako ohrožený druh (EN).[2][3][4][7]
Obrázky, zvuky či videa k tématu lachtan šedý ve Wikimedia Commons
Lachtan šedý (Neophoca cinerea) je endemický ploutvonožec obývající pobřeží Austrálie, jediný druh monotypického rodu Neophoca z čeledě lachtanovitých. Jako jediní z ploutvonožců mají nesynchronní reprodukční cyklus trvající průměrně 17,5 měsíce.
Der Australische Seelöwe (Neophoca cinerea) ist eine große Ohrenrobbe australischer Küsten.
Die Bullen dieser Seelöwen werden bis zu 2,5 m lang und 300 kg schwer. Kühe sind mit 1,8 m und 100 kg sehr viel kleiner. Auch in der Farbe unterscheiden sich die Geschlechter stark: Männchen sind dunkelbraun gefärbt, Weibchen dagegen silbergrau oder hellbraun und an der Unterseite heller als an der Oberseite.
Die Kolonien finden sich entlang der Küsten West- und Südaustraliens. Sie liegen meistens auf kleinen unbewohnten Inseln, die der Küste vorgelagert sind. Dies ist nur ein Teil der ehemaligen Verbreitung, die im 19. Jahrhundert bis nach Tasmanien und New South Wales reichte. Australische Seelöwen wandern wenig umher und bleiben meistens auch außerhalb der Fortpflanzungszeit in der Nähe ihrer Kolonien. Die weiteste belegte Entfernung eines Australischen Seelöwen von seiner Kolonie betrug nur 300 km.
Das Fortpflanzungsverhalten gleicht dem anderer Ohrenrobben: Die Bullen erreichen die Küste vor den Kühen und versuchen dort, in oftmals blutigen Kämpfen die besten Territorien für sich zu erstreiten. Dadurch werden schwächere Männchen an den Rand der Kolonie gedrängt. Wenn die Weibchen eintreffen, entscheidet der Ort ihres Landgangs, zu welchem Harem sie gehören werden. In den Kolonien herrscht eine erhebliche Unruhe durch jüngere Männchen, die Momente der Unaufmerksamkeit eines alten Bullen zu nutzen versuchen, um sich mit einem der Weibchen seines Territoriums zu paaren. Zudem sind die Bullen unentwegt dabei, Weibchen am Verlassen des Territoriums zu hindern. Hierzu folgen sie einer Kuh auch in Nachbarreviere, was zu neuen Kämpfen mit den dortigen Bullen führen kann. Ein ähnlich hoher Aggressionsgrad der Bullen kann nur noch bei der Mähnenrobbe beobachtet werden.
Verglichen mit den zwei anderen Robben australischer Küsten, dem Neuseeländischen Seebären und dem Südafrikanischen Seebären, ist der Australische Seelöwe eine seltene Robbe. Der Gesamtbestand wird auf höchstens 12.000 Tiere geschätzt. Obwohl er nie so häufig wie die vorgenannten Arten war, war er dennoch einst weiter verbreitet und zahlreicher als heute.
Die IUCN listet den Australischen Seelöwen auf der Roten Liste der gefährdeten Arten als endangered (stark gefährdet).[1]
Der Australische Seelöwe (Neophoca cinerea) ist eine große Ohrenrobbe australischer Küsten.
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.[2] It is currently monotypic in the genus Neophoca, with the extinct Pleistocene New Zealand sea lion Neophoca palatina the only known congener.[3] With a population estimated at around 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.[2] 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.
Australian sea lions are sparsely distributed across their range, from the Houtman Arbrolhos Islands (28°S, 114°E) in Western Australia, along the southern Australian coast to The Pages Islands (35°46’S, 138°18’E) in South Australia. Sixty-six (66) breeding colonies have been identified, with 28 in Western Australia and 38 in South Australia.[4]
Most breeding colonies exist on offshore islands, with the exception of Point Labatt in South Australia, Baxter Cliffs (west of Twilight Cove) in Western Australia, and the Bunda Cliffs, Great Australian Bight, which straddles the border between the two states. Forty-two (42%) percent of the total known population are found within the three largest colonies east of Port Lincoln; Seal Bay (on Kangaroo Island’s south coast), The Pages and Dangerous Reef (in Spencer Gulf).[4]
The species' breeding range has contracted as the population has fallen. Now-extinct breeding colonies previously existed in the Bass Strait, particularly on Clarke Island and adjacent islands in the Furneaux Group. The Abrolhos Island breeding colony is believed to be much smaller today than it was prior to European settlement. Kangaroo Island's northeasterly coasts, in addition to some islands near Perth and Albany, once hosted now-extinct breeding colonies.[4]
The Australian sea lion is a pinniped, most closely related to other species of sea lions and fur seals making up the family Otariidae.[5] These mammals use their flippers to propel themselves in water and can walk on land with their flippers. Australian sea lions share distinct features with other sea lions. These include short fur, short flippers and a bulky body.[6]
In pinnipeds, mothers and pups are frequently separated throughout nursing and are thus expected to have evolved an efficient individual recognition system. Consequentially, in Australian sea lions, as in many social mammals, mothers and their offspring can identify each other. Individual recognition produces mutual benefits by avoiding misdirected maternal care and therefore energy expenditure for mothers, and the risk of injury for young approaching unrelated, potentially dangerous, adult females. Individual recognition can be accomplished with a combination of several sensory modalities, including olfaction, vision, and audition. The use of olfactory cues as a close range recognition mechanism allows mothers to further confirm their pup's identity. In contrast to recent olfactory studies in pinnipeds which showed the presence but not a natural function of olfaction in pinnipeds, the present study shows that wild Australian sea lions use their olfactory abilities in a functional manner, by discrimination between the scents of their own offspring and a non-filial pup.[7] However, in a dynamic, crowded colony, the acoustic channel seems to be the most reliable modality. For pinnipeds, neither visual nor olfactory cues are likely to be the primary modality for mother–pup recognition.[8]
Male Australian sea lions were observed producing three different call types: a barking call, a bleating call and a female-like call. The predominant call type produced by males of all ages was the barking call. The barking call of Australian sea lions was similar in structure to the barking calls described in some other species of otariid in that it was a short sound produced repetitively in a series. Mature Australian sea lion males were found to emit the barking call in almost all social interactions, despite the existence of at least three call types in their vocal repertoire, plus a guttural threat and growl.[9]
While Australian sealions have a reputation for curiosity and playfulness during interactions with humans, their bite (albeit rare) can require hospitalisation.[10]
Australian sea lions have been described as opportunistic, benthic foragers. Limited stomach content and faecal analyses have identified a wide variety of prey in the diet of the Australian sea lion, including teleost fish, squid, cuttlefish, octopus, sharks (including Port Jackson sharks), Southern rock lobster, other small crustaceans and Little penguins. Regurgitate and stomach samples from Australian sea lions at Seal Bay contained hard parts consisting predominantly of benthic taxa. This supports previous evidence that this species forages primarily on neritic, benthic prey, many of which are non-migratory. For the cephalopod component of the Australian sea lion diet, octopus and giant Australian cuttlefish made up the greatest biomass of prey taxa. Although the Australian sea lion feeds off seasonally available prey such as semelparous cephalopods, it also exploits prey species that are available throughout the year, such as Southern rock lobster and many fish species.[11]
Observations from the 1930s in Western Australian noted that Australian sea lions seemed to be subsisting on little penguins during the summer, and that their regular diet didn't compete with commercial fisheries.[12] Also in the 1930s, the animal was described informally as "rather fond of penguins".[13] They were known to feed on little penguins in the 1960s.[14]
Adult Australian sea lions are eaten by great white sharks and orca (killer whales); pios are vulnerable to attack by other smaller shark species. Additionally, pups may be inadvertently killed by other animals, such as stingrays. The young and naïve sea lions may become overly curious or confident, possibly even hunting rays, and receive a lethal sting. The blue-ringed octopus may also spark a young animal’s curiosity; a fatal error, with blue-ringed octopi being among the most poisonous, deadliest cephalopods. They may also be killed by larger male sea lions and fur seals, if they are smaller, weaker or alone and vulnerable.[15]
As of 2020, 66 breeding colonies have been identified: 28 in Western Australia and 38 in South Australia.[4] The animals breed on at least 50 islands, 27 in Western Australia and 23 in Southern Australia. Prior to a study that took place from 1987 to 1992, thirty-one of the 50 islands were undiscovered, as well as 19 more islands considered additional breeding grounds.[16] On the basis of surveys conducted primarily in 1990, about 70% of the population was in Southern Australia and 30% in Western Australia.[17] Pup production was estimated at 2,432 for these 50 islands in 1990. In 1994 and 1995 another 10 breeding colonies were recorded on the mainland in the Great Australian Bight region, only producing 161 pups.[17] Reproduction is yielding fewer and fewer pups per breeding season. The four largest colonies, on The Pages Islands, at Seal Bay on Kangaroo Island, and at Dangerous Reef, produced 42% of the total pup numbers; they are at the eastern end of the range, east of Port Lincoln.[17]
The breeding cycle of the Australian sea lion is unusual within the pinniped family. It is a 17.6- to 18-month cycle and is 'not' synchronised between colonies. However, census data collected since 1973 shows that breeding events shift forward in time to 13.8 days earlier every 18 months.[18] The duration of the breeding season can range from five to seven months and has been recorded for up to nine months at Seal Bay on Kangaroo Island.
Bulls do not have fixed territories during the breeding season. The males fight other males from a very young age to establish their individual positions in the male hierarchy and during the breeding season, dominant males will guard females for the right to breed with her when she comes into oestrus. A female comes into season for about 24 hours within 7 to 10 days after she has given birth to her new pup. She will only look after the new pup and generally fights off the previous season's pup if it attempts to continue to suckle from her. Male Australian sea lions are also known to kill young as an act of defence of territory.
Australian sea lions also practice alloparental care, in which an adult may adopt the pup or pups of another. This might take place if the original parents die or are for some reason separated from them. This behaviour is common and is seen in many other animal species such as the elephant and fathead minnow.[19]
In 2010, an estimated 14,730 Australian sea lions existed.[20] By 2014, the population had dropped to an estimated 6,500 and continues to decrease. The population is listed as Endangered on the IUCN Red List of Threatened Species.[21] The Australian sea lion population is naturally disadvantaged when compared to other pinnipeds in Australia. Its long and complicated breeding cycle, the high site fidelity of females, and high mortality rates all make the species more vulnerable to extinction.[4]
Jones Island, west of Eyre Peninsula in South Australia is one of the few sites where the population is not decreasing. In 2019, it was declared a "prohibited area" to eliminate human disturbance to the colony while landed.[22]
In 2018, aerial drones were being used to search for, discover and measure colonies of Australian sea lions along the Nullarbor Plain. Previously, surveying these areas was limited to the use of binoculars and peering down 60 metre high cliffs to view the rocks below.[23]
Australian sea lions should only be approached in the company of a park ranger. They may exhibit defensive behavior including biting.[24] Sea lions have historically been captured from the wild and held in captivity in various zoos and aquaria, including Marineland of South Australia.
Sea lions were heavily hunted following European settlement which greatly reduced their numbers. Large-scale hunting ceased in the 1920s,[25] but some killing and trade in "hair seal" skins continued.[26] No baseline population data exists, but the species population and range have both decreased.
Sea lions on Dangerous Reef were shot and butchered for use as shark bait during the 1960s and 1970s. Between 1964 and 1975, conservationist Valerie Taylor saw the colony there reduce from over 200 animals to between 60 and 80 animals based on her own population counts in both years. She described noticing the difference in the animals response to humans from her early visit in the 1960s to her follow up in the 1970s, when the animals on both Dangerous Reef and Hopkins Island demonstrated fear of humans. In the 1980s, Australian sea lions were entangled in gill nets, after which fishers shot them and used them as shark bait.[27]
Major threatening processes in the 20th and 21st centuries were primarily interactions with commercial fishing gear and illegal shooting.[28] Entangled animals can sometimes be found and treated successfully.[29]
Secondary threats include: marine fish aquaculture (including loss of habitat, entanglement and direct killing), disease, pollution, oil spills and noise, particularly from seismic surveys, construction, or marine operations.[23]
Illegal shootings have been reported in both South Australia and Western Australia. Dead animals with gunshot wounds have been found at Cheynes Beach, Albany,[30] near Port Wakefield in South Australia[31] and at other locations. Some killings have led citizens to start petitions demanding thorough investigation.[32] The shooting of a male Australian sea lion which had hauled out at Port Macdonnell in 2013 by government employees without a prior veterinary assessment was criticised by animal rescue workers and the general public.[33][34] In March 2021, a male Australian sea lion was shot and killed with a longbow at Bales Beach, Kangaroo Island.[35]
Australian sealions are caught as bycatch by the Southern and Eastern Scalefish and Shark Fishery. Following the closure of the Commonwealth gillnet fishery in southern Spencer Gulf in 2001, pup production increased at Dangerous Reef (within Spencer Gulf) and that population began to recover.[4]
Researchers estimated that while the fishery was operating, 374 Australian sea lions were killed by the fishery each breeding cycle. While most sealion bycatch occurred close to breeding colonies, some occurred as far as 130 kilometres away.[4] In 2011, Humane Society International lobbied for the trigger figure for the closure of the fishery of 104 Australian sea lion deaths to be lowered.[36]
Some Australian sealions have drowned after becoming entangled or trapped in Southern rock lobster pots and gear. Commercial fishers have also illegally shot and killed Australian sealions which they believed were competing with their fishery.[4]
The transition for young mammals from dependence on milk to independent foraging can lead to increased risk of natural mortality. The Australian sea lion demonstrates one of the longest lactation periods in pinnipeds and pups begin diving before they are weaned. Australian sea lion adults work hard to forage at the seabed, demonstrating high field metabolic rates, and spending 58% of time at sea diving and 35% of time at sea on or near the bottom. Juveniles spend 67% of time at sea diving and 44% of time at sea on or near the bottom. Although many air-breathing vertebrates dive well within their estimated limit of oxygen stores, Australian sea lion adults and juveniles appear to operate close to their physiological maximum. The prolonged dependency period could provide extensive opportunities for foraging lessons, while the extreme diving behaviour required in the Australian sea lions' environment might necessitate it. Alternatively, it has hypothesised that female harbour seals accompanying pups demonstrate reduced foraging efficiency, and hence, the metabolic demands of foraging for Australian sea may preclude lactating females from performing suboptimal dives with their young. This becomes a preventative measure to maintain a population and avoid a complete extinction. However, as a result of small population size, small breeding colony size, low reproductive rate, exposure to human activities, and evidence of population declines in some areas, Australian sea lions have recently been listed as threatened and vulnerable.[37]
The protection of breeding habitat for the Australian sealion has been a conservation priority since the early 20th century. In 1909, field naturalists lobbied for the protection of three critical breeding sites for the Australian sea lion: Dangerous Reef, The Pages and the Casuarina Islets off Kangaroo Island.[38] In 1918, the South Australian parliament debated the Birds and Animals Protection Bill, and the Legislative Council agreed that it would protect Australian sea lions from harm covering waters of Spencer Gulf, St Vincent Gulf, the Investigator Strait, Backstairs Passage and to the mouth of the Murray River.[39] The introduction of the South Australian National Parks and Wildlife Act 1972 prohibited the killing of Australian sea lions statewide.
In 2005, the Australian sea lion was listed as Vulnerable under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 and is similarly listed in each state across its range (South Australia and Western Australia). On 11 June 2013, the Recovery Plan for the Australian sea lion (Neophoca cinerea) was adopted by the Minister for Sustainability, Environment, Water, Population and Communities. The plan considers the conservation requirements of the species across its range and identifies the actions to be taken to ensure its long-term viability in nature and the parties that will undertake those actions.[40] In November 2014, the species was assessed by the International Union for the Conservation of Nature as Endangered.[41]
Some zoos and aquariums are participating in captive breeding programs.[45] In 2006 it was reported that at least 41 pups had been born and raised in captivity since 1981. The species has been kept in aquaria since at least as early as 1965.[46] In 2015, an Australian sea lion juvenile was captured at Bletchley near Strathalbyn in South Australia, and was going to be considered for holding in captivity.[47]
The Australian Fisheries Management Authority Commission finalised an Australian Sea Lion Management Strategy which came into force on 30 June 2010. This included closures of waters around colonies, seasonal closures, increased observation of sea lion activity and trials of modified fishing techniques and equipment. The strategy was designed to meet the commission's obligations under the Fisheries Management Act 1991 and the Environment Protection and Biodiversity Conservation Act 1999. The strategy was expected to significantly reduce the impact of fishing in the Southern and Eastern Scalefish and Shark Fishery (SESSF) on Australian sea lions and enable the recovery of the species, including all sub-populations.[48]
Southern rock lobster fisheries in both South Australia and Western Australia use pots which feature special collars designed to prevent Australian sea lions from entering the pots or spikes which act as a deterrent.[4]
Australian sea lions defecate nutrient-rich faeces which may provide an important nutrient source for coastal ecosystems. Metagenomic analysis of the bacterial consortia found in the faeces of Australian sea lions found very high levels of nutrient cycling and transport genes which may break down the nutrients defecated by sea lions into a bioavailable form for incorporation into marine food webs.[49]
Diving behaviours indicate that the Australian Sea Lions worked extremely hard to exploit the benefits of their surrounding habitats. The Australian sea lion exceeds the limit (calculated aerobic dive limit) on 79% of dives. Australian sea lions spend 58% of time at sea diving and demonstrate high field metabolism,[50] which allows the sea lions to maximise their time spent at or near the benthos, with 61% of each dive and 35% of their time at sea being spent at the deepest 20% of the dives.[51] When diving, these animals are spending 57.9% of their time at sea spent at depths greater than or equal to 6 m, which can be considered as continuous diving.[51] Seasonal variability in foraging energetics and dive behaviour is likely to be sensitive to regional oceanography, the maintenance costs of female sea lions and their offspring, and the distribution and behaviour of their prey.
The Australian sea lion exhibits strong site fidelity, with a foraging range of at most 300 km from their colony. Australian sea lions sometimes travel inland during tumultuous weather, and have been known to travel up to 9.4 km from the ocean.[52]
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 in the genus Neophoca, with the extinct Pleistocene New Zealand sea lion Neophoca palatina the only known congener. With a population estimated at around 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.
El león marino australiano (Neophoca cinerea) es una especie de mamífero pinnípedo de la familia de los otáridos endémica de Australia.[2] Cazada casi hasta la extinción, esta mamífero marino está protegido en la actualidad.
Al nacimiento las crías miden entre 60 y 70 cm y pesan entre 6,5 y 8 kg. Los machos adultos pueden crecer hasta 2,5 m y pesan 300 kg. Las hembras hasta 1,8 m y alcanzan un peso de 105 kg. Las hembras alcanzan la madurez a los 3 años de edad, mientras los machos maduran hasta los seis años. Tienen una cabeza grande con un hocico largo, estrecho y afilado. El cráneo posee una cresta sagital de 3 cm. Sus pabellones auriculares, son muy pequeñas y se encuentran muy adosados a la cabeza.[3]
El león marino australiano se distribuye al sudeste de Australia desde la isla Canguro al occidente hasta las islas Houtman Albrolhos hacia el oriente. La población para 2008 se estimaba en 13 790 individuos con un número de 3380 nacimientos al año (2674 en el sur de Australia y 706 al occidente de Australia).[1]
En 2008 la especie fue catalogada en la Lista Roja de la IUCN como amenazada (del inglés Endangered (EN)), justificado por el pequeño tamaño de la población y la declinación de algunas colonias; adicionalmente las poblaciones más grandes están bajo amenaza por las capturas accidentales por la pesca comercial.[1]
El león marino australiano (Neophoca cinerea) es una especie de mamífero pinnípedo de la familia de los otáridos endémica de Australia. Cazada casi hasta la extinción, esta mamífero marino está protegido en la actualidad.
Neophoca cinerea Neophoca generoko animalia da. Artiodaktiloen barruko Otariidae familian sailkatuta dago..
Neophoca cinerea Neophoca generoko animalia da. Artiodaktiloen barruko Otariidae familian sailkatuta dago..
Neophoca cinerea
Le lion de mer australien (Neophoca cinerea) est la seule espèce d'otaries du genre Neophoca, de la sous-famille des otarinés (Lion de mer). Il se reproduit uniquement sur les côtes sud de l'Australie. À l'heure actuelle, il reste encore environ 12 000 lions de mer australiens protégés par the Australian National Parks and Wildlife Act de 1972 qui en a interdit la chasse commencée avec l'arrivée des immigrants européens sur le continent.
Le lion de mer australien ne vit que dans l’océan proche des côtes australiennes. Il se nourrit uniquement en mer, où il chasse les poissons, calamars et autres animaux marins. Ses nageoires pectorales lui permettent de se déplacer rapidement dans l'eau et il peut se mouvoir facilement sur le sol en marchant sur ses quatre nageoires.
Le cycle de reproduction du lion de mer australien est le plus original de toute la famille des Otariidés. La durée de gestation est de 18 mois mais la période de mise bas varie selon les colonies: elle s'étale sur 5 à 7 mois et peut même atteindre 9 mois à Seal Bay (la baie des otaries) sur Kangaroo Island.
Les mâles n'ont pas de territoire particulier pendant la saison de reproduction. Dès leur plus jeune âge, ils se battent entre eux pour établir une hiérarchie et les mâles dominants auront le droit de s'accoupler avec les femelles lorsqu'elles seront fécondables (Œstrus). Une femelle devient fertile pendant 24 heures, 7 à 8 jours après la mise bas. Après mise bas, elle ne s'occupe que de son dernier petit et va chasser celui de la précédente portée s'il vient chercher à la téter.
Comme chez les autres espèces d'Otariidae, le dimorphisme sexuel est très marqué, le mâle étant beaucoup plus grand et lourd que la femelle. Chez cette espèce, les mâles mesurent 2,5 m et pèsent de 250 kg, tandis que les femelles mesurent entre 1,8 m de long et pèsent de 105 kg[1].
Neophoca cinerea est sur la liste non exhaustive des animaux véritablement en danger d'extinction (fournie par l'UICN).
Régime alimentaire
Prédateurs
Neophoca cinerea
Le lion de mer australien (Neophoca cinerea) est la seule espèce d'otaries du genre Neophoca, de la sous-famille des otarinés (Lion de mer). Il se reproduit uniquement sur les côtes sud de l'Australie. À l'heure actuelle, il reste encore environ 12 000 lions de mer australiens protégés par the Australian National Parks and Wildlife Act de 1972 qui en a interdit la chasse commencée avec l'arrivée des immigrants européens sur le continent.
Le lion de mer australien ne vit que dans l’océan proche des côtes australiennes. Il se nourrit uniquement en mer, où il chasse les poissons, calamars et autres animaux marins. Ses nageoires pectorales lui permettent de se déplacer rapidement dans l'eau et il peut se mouvoir facilement sur le sol en marchant sur ses quatre nageoires.
Le cycle de reproduction du lion de mer australien est le plus original de toute la famille des Otariidés. La durée de gestation est de 18 mois mais la période de mise bas varie selon les colonies: elle s'étale sur 5 à 7 mois et peut même atteindre 9 mois à Seal Bay (la baie des otaries) sur Kangaroo Island.
Les mâles n'ont pas de territoire particulier pendant la saison de reproduction. Dès leur plus jeune âge, ils se battent entre eux pour établir une hiérarchie et les mâles dominants auront le droit de s'accoupler avec les femelles lorsqu'elles seront fécondables (Œstrus). Une femelle devient fertile pendant 24 heures, 7 à 8 jours après la mise bas. Après mise bas, elle ne s'occupe que de son dernier petit et va chasser celui de la précédente portée s'il vient chercher à la téter.
Il leone marino australiano (Neophoca cinerea Péron, 1866) è un mammifero pinnipede appartenente alla famiglia delle otarie. È l'unica specie del genere Neophoca[2].
Alla nascita, i cuccioli sono grandi circa 60-70 cm e pesano circa 6-8 kg. La loro pelliccia è inizialmente marrone cioccolato. Le differenze fra maschi e femmine adulti sono molto evidenti, un adulto maschio cresce circa fino a 2,5 metri e pesa 300 kg, una femmina invece cresce fino ad una lunghezza di circa 1,8 metri e pesa circa 105 kg. Le femmine raggiungono la maturità sessuale a circa 3 anni di età, i maschi invece la raggiungono dai 6 anni di età o più anziani. I maschi si scuriscono ulteriormente quando diventano più adulti. I leoni marini australiani hanno una grande testa, il cranio ha una cresta sagittale di circa 30 mm di altezza, le orecchie sono incredibilmente piccole e si trovano vicino alla testa. I giovani sono color marrone scuro. Gli adulti maschi e femmine hanno una pelliccia grigio-argento in cima e di colore giallo pallido - marrone chiaro sul fondo.
I leoni marini australiani vivono lungo le coste dell'Australia meridionale e occidentale, comprese alcune isole adiacenti. In Tasmania, dove erano un tempo presenti, sono invece estinti. L'areale riproduttivo va dalle isole Pages (poco a oriente dell'Isola dei Canguri) alle isole Houtman Abrolhos presso la costa australiana occidentale.[1]
I leoni marini non sono migratori, difatti vivono sulle spiagge di sabbia vicino al luogo della loro nascita, per questo motivo vengono a formarsi grandi colonie. La distanza massima registrata per un esemplare è stato contrassegnato 300 chilometri dal luogo della sua nascita.
Il leone marino australiano (Neophoca cinerea Péron, 1866) è un mammifero pinnipede appartenente alla famiglia delle otarie. È l'unica specie del genere Neophoca.
Australinis jūrų liūtas (lot. Neophoca cinerea, angl. Australan sea lion) – ausytųjų ruonių (Otariidae) šeimai priklausantys ruoniai, aptinkami prie vakarinių ir pietinių Australijos salų.
Didžiausios populiacijos yra Kengūrų ir Pavojingo rifo salose (Australijos pietūs). Suaugę patinai sveria 300 kg, o patelės 105 kg. Minta kalmarais, sepijomis, pingvinais (Eudyptula minor), gaudo smulkius ryklius, rajas, plačiakrūtinius merlangus bei aštuonkojus. Vikiteka
Australinis jūrų liūtas (lot. Neophoca cinerea, angl. Australan sea lion) – ausytųjų ruonių (Otariidae) šeimai priklausantys ruoniai, aptinkami prie vakarinių ir pietinių Australijos salų.
Didžiausios populiacijos yra Kengūrų ir Pavojingo rifo salose (Australijos pietūs). Suaugę patinai sveria 300 kg, o patelės 105 kg. Minta kalmarais, sepijomis, pingvinais (Eudyptula minor), gaudo smulkius ryklius, rajas, plačiakrūtinius merlangus bei aštuonkojus. Vikiteka
De Australische zeeleeuw (Neophoca cinerea) is een zeeroofdier uit de familie der oorrobben. De Australische zeeleeuw komt enkel voor langs de kust van Zuid-Australië.
De Australische zeeleeuw kent seksuele dimorfie. Vrouwtjes zijn veel kleiner dan mannetjes, hebben een ander kleurpatroon en missen de lange manen. Het vrouwtje heeft zilvergrijze flanken en rug, met een roomgele tot beige buik en kop. Ze wordt 130 tot 180 centimeter lang en 70 tot 110 kilogram zwaar. Het volwassen mannetje heeft een zwartachtige donkerbruine vacht, met een lichtere borst en een donker gezichtsmasker. Jonge mannetjes hebben een vacht die meer op dat van vrouwtjes lijkt. Over de schouders loopt een maan van lange, ruwe haren. Het mannetje wordt 200 tot 250 centimeter lang en 250 tot 300 kilogram zwaar.
De Australische zeeleeuw komt enkel voor op eilanden en in de kustwateren van West- en Zuid-Australië, waar zo'n tien- tot twaalfduizend dieren leven. Ze trekken zelden ver weg van de kust, en blijven meestal boven het continentaal plat. De Australische zeeleeuw eet inktvissen en vissen, waaronder wijting, zalm, haaien en roggen. Soms eten ze kreeftachtigen. Een enkele keer is waargenomen dat Australische zeeleeuwen pinguïns op het land vingen en doodden.
In de paartijd (meestal oktober tot december, maar afhankelijk van de locatie) verzamelen de zeeleeuwen zich op de werpstranden, in groepen van zo'n tweehonderd dieren. Als werpstrand geeft het vrouwtje de voorkeur voor zandstranden of stranden met kleine, ronde stenen. Mannetjes zijn territoriaal, en zullen meestal andere mannetjes uit hun territorium wegjagen. Tien dagen na de worp vindt de paring plaats.
Jongen worden pas zo'n 18 maanden na de paring geboren. Dit komt doordat de Australische zeeleeuw een verlengde draagtijd kent: de bevruchte eicel blijft voor een periode van 3,5 tot 5 maanden niet in ontwikkeling. Hierna volgt de eigenlijke draagtijd van zo'n veertien maanden, meer dan die van enig ander zeeroofdier.
Pasgeboren jongen hebben een chocoladebruine vacht met een bleek geelbruine kruin. Ze zijn 62 tot 68 centimeter lang en 6,4 tot 7,9 kilogram zwaar. Na twee maanden wordt deze ingewisseld voor een vacht die meer lijkt op die van een volwassen vrouwtje. Als de moeder op jacht gaat, verzamelen de jongen zich in zogenaamde crèches. De moeder vindt haar eigen jong weer terug dankzij de roep, die voor ieder jong uniek is.
Jongen worden meestal gezoogd totdat het volgende jong wordt geboren, dus zo'n achttien maanden later. Vrouwtjes zijn na 4,5 tot 6 jaar geslachtsrijp, mannetjes vanaf zes jaar.
Bronnen, noten en/of referentiesDe Australische zeeleeuw (Neophoca cinerea) is een zeeroofdier uit de familie der oorrobben. De Australische zeeleeuw komt enkel voor langs de kust van Zuid-Australië.
Australsk sjøløve (Neophoca cinerea) er en sjøløve i øreselfamilien. Den finnes på sør- og vestkysten av Australia.
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Multimedia w Wikimedia Commons Otarka australijska[4], uchatka australijska (Neophoca cinerea) – gatunek drapieżnego ssaka morskiego z rodziny uchatkowatych, zamieszkujący wybrzeża Australii[5]. Żywi się rybami, kalmarami, skorupiakami i innymi morskimi zwierzętami. Uchatki te pożywiają się tylko w morzu. Mają od 1,5 do 2,5 m długości i osiągają masę ciała 250 - 300 kg. Żyją do 25 lat. Dzisiaj ich populacja wynosi około 10000 osobników. Gatunek jest wpisany na listę zwierząt zagrożonych.
Otarka australijska, uchatka australijska (Neophoca cinerea) – gatunek drapieżnego ssaka morskiego z rodziny uchatkowatych, zamieszkujący wybrzeża Australii. Żywi się rybami, kalmarami, skorupiakami i innymi morskimi zwierzętami. Uchatki te pożywiają się tylko w morzu. Mają od 1,5 do 2,5 m długości i osiągają masę ciała 250 - 300 kg. Żyją do 25 lat. Dzisiaj ich populacja wynosi około 10000 osobników. Gatunek jest wpisany na listę zwierząt zagrożonych.
Neophoca cinerea, popularmente conhecida como leão-marinho-australiano, é uma espécie de mamífero marinho da família Otariidae. É a única espécie descrita para o gênero Neophoca.[1] Endêmica da Austrália.
A espécie é endêmica da Austrália, ocorrendo das ilhas Pages e ilha Kangaroo na Austrália Meridional ate o Abrolhos Houtman na Austrália Ocidental.[2]
O ciclo reprodutivo do leão-marinho-australiano é incomum dentro do grupo dos pinípedes. É um ciclo de 18 meses e não é sincronizada entre as colônias. A duração da época de reprodução pode variar de cinco a sete meses e foi registrada por até nove meses, em Seal Bay na ilha Kangaroo.
Machos não estabelecem territórios durante a época de reprodução, entretanto, lutam com outros machos a partir de uma idade muito jovem, para estabelecerem suas posições individuais na hierarquia masculina e durante a época de reprodução, os machos dominantes defendem suas fêmeas e lutam pelo direito de acasalar com elas, somente quando elas entram no cio. A fêmea entra no cio por cerca de 24 horas, dentro de 7 a 10 dias depois que deu à luz. Ela só vai cuidar do filhote novo, que geralmente disputa com filhote da temporada anterior, se ele continuar a mamar nela. Leões-marinhos-australianos machos também são conhecidos por matar machos jovens, como um ato de defesa para impor sua autoridade.
A espécie também pratica o cuidado aloparental, em que um adulto pode tomar o filhote ou cuidar dos filhotes de outro leão-marinho. Isso pode acontecer se os pais originais morrerem ou por algum motivo abandonarem seus filhotes. Este comportamento é comum e é visto em muitas outras espécies de animais como elefantes e em algumas aves.[3]
A União Internacional para Conservação da Natureza (IUCN) classifica a espécie como "em perigo" de extinção devido a distribuição geográfica restrita e a redução do tamanho populacional.[2] Na Austrália, o Environment Protection and Biodiversity Conservation Act 1999 (EPBC) de 14 de fevereiro de 2005 considera a espécie como vulnerável.[4] A Austrália Meridional considera o animal vulnerável e sob proteção pelo National Parks and Wildlife Act 1972 de 16 de maio de 2013,[5] e a Austrália Ocidental como parte da "fauna sob proteção especial" através do Wildlife Conservation Act 1950 de 4 de dezembro de 2014.[6]
Em 11 de junho de 2013, o Minister for Sustainability, Environment, Water, Population and Communities adotou o Recovery Plan for the Australian Sea Lion (Neophoca cinerea). O plano considera as necessidades de conservação da espécie em toda sua distribuição e identifica as ações a serem tomadas para garantir a sua viabilidade a longo prazo na natureza e as partes que irão realizar essas ações.[7]
A Australian Fisheries Management Authority Commission (AFMA) também finalizou o Australian Sea Lion Management Strategy, que entrou em vigor em 30 de junho de 2010 e estabelece o isolamento das águas ao redor das colônias, paradas sazonais na atividade pesqueira, monitoramento da atividade dos leões-marinhos e pesquisa de técnicas e equipamentos da atividade pesqueira que tragam menos risco a espécie. A estratégia foi concebida para satisfazer as obrigações do Fisheries Management Act 1991 e Environment Protection and Biodiversity Conservation Act 1999. A ação irá reduzir significativamente o impacto da pesca na área de ocorrência dos leões-marinhos e permitir a recuperação da espécie, incluindo todas as subpopulações existentes na costa australiana.[8]
|acessodata= (ajuda) Neophoca cinerea, popularmente conhecida como leão-marinho-australiano, é uma espécie de mamífero marinho da família Otariidae. É a única espécie descrita para o gênero Neophoca. Endêmica da Austrália.
Australiskt sjölejon (Neophoca cinerea) är en art i familjen öronsälar.
Hanar blir vanligen 180 till 250 centimeter långa och cirka 180 till 250 kilogram tunga (ibland upp till 300 kg). Honor är med en längd av 130 till 180 centimeter och en vikt av 61 till 105 kilogram betydligt mindre.[1][2] Färgen är hos hannarna mörkbrun och hos honorna silvergrå eller ljusbrun. Honor har dessutom en ljusare undersida som kan vara lite gulaktig.[2]
Ungar är vid födelsen 60 till 70 cm långa och 6,5 till 8 kg tunga. De har en mörkbrun päls och en svartgrå ansiktsmask.[2]
I motsats till Hookers sjölejon har arten bara 5 kindtänder i överkäken. Australiskt sjölejon har dessutom 3 framtänder i överkäken, 2 framtänder i underkäken, en hörntand i varje käkhalva och 5 kindtänder i underkäken, alltså 34 tänder.[3]
Kolonier finns längs kustlinjen av västra och södra Australien. De förekommer mest på små öar som ligger nära kusten.[1] På 1800-talet fanns denna art även på Tasmanien och i New South Wales. Australiska sjölejon vandrar sällan och stannar utanför parningstiden i närheten av kolonierna. Den längsta avstånd från sin koloni som en individ av hankön har observerats på var bara 340 kilometer.[1]
Arten jagar olika havslevande djur och födans sammansättning kan variera mycket mellan olika individer. Ett favoritbyte är bläckfiskar. Dessutom äter australiskt sjölejon större fiskar som filfiskar (Monacanthidae), läppfiskar (Labridae), beryxfiskar (Berycidae) eller rockor. Ibland fångar arten mindre fiskar och kräftdjur.[1]
Arten jagar vanligen nära vattenytan till ett djup av 37 meter.[2] Ungdjur och honor når ibland ett djup av 90 till 130 meter under födosöket och hanar når ibland ett djup av 150 meter. I sällsynta fall kan hanar dyka till 250 meter under havsytan. Individerna stannar upp till 8 minuter under vattenytan och kan dyka 10 till 11 gånger per timme. En vandring till havs är hos ungdjur och honor 1 till 6 dagar lång och hos hanar 2,5 till 6,7 dagar lång. Jakten sker alltid på dagen, under natten håller sig australiskt sjölejon vid vattenytan eller individen vilar på land.[1]
Parningen sker på liknande sätt som hos andra öronsälar. Först strider hannarna om en bra plats i kolonin som ger möjlighet för många parningar. Svaga hannar trängs till kolonins utkant där de sällan får tag i honor. Unga hannar försöker alltid locka bort honor från etablerade hannar. Dessutom hindrar framgångsrika hannar sina honor från att lämna platsen.[3] Det medföljer ibland att en hanne hamnar i en annan hannes revir, vilket försvaras ivrigt. Liknande aggressivitet hos sälhannar finns bara hos sydamerikanskt sjölejon.
I motsats till alla andra sälar är parningstiden hos australiskt sjölejon inte kopplad till någon årstid. Mellan två fortplantningstider ligger 17 till 18 månader och de varierar mellan olika kolonier. Betraktad över hela utbredningsområdet förekommer nästan alltid en eller flera kolonier där fortplantningen pågår. Fortplantningstiden är mellan fyra och nio månader lång.[1]
Efter parningen vilar det befruktade ägget 4 till 6 månader innan den egentliga dräktigheten börjar. Den är sedan upp till 14 månader lång (vanligen 12 månader[2]). Honan föder allmänt en enda unge per kull och stannar de första 9 till 10 dagar vid ungen. Modern slutar vanligen efter 15 till 18 månader med digivning kort före den nästa kullen. När modern inte blir dräktig igen eller när den efterföljande ungen dör kan den första ungen dia sin mor upp till tre år. Ungar besöker i början vattenpölar eller det grunda vattnet vid stranden och efter det första pälsbytet som sker efter fyra månader utforskar de även havet. Könsmognaden infaller för honor efter 4,5 till 6 år och för hanar efter 6 år eller ännu senare.[1]
Jämfört med andra sälarter i samma område är australiskt sjölejon en sällsynt art. Beståndet uppskattas till 12 700 individer och antalet vuxna individer som kan fortplanta sig antas vara 6 500 (2010).[1] Det har aldrig funnits så stora kolonier som hos sydafrikansk pälssäl eller Nya Zeelands pälssäl men ändå var beståndet tidigare större.
Australiskt sjölejon jagades av Australiens ursprungsbefolkning sedan flera tusen år och den jagades under 1700- och 1800-talet av europeiska säljägare. Det första lagliga förbudet att jaga arten undertecknades redan 1889. Förbudet uppdaterades sedan flera gånger. Under nyare tider dör individer när de hamnar av misstag i fiskenät eller genom sjudomar samt vattenföroreningar. IUCN listar arten som starkt hotad (endangered).[1]
Wikimedia Commons har media som rör Australiskt sjölejon.
Australiskt sjölejon (Neophoca cinerea) är en art i familjen öronsälar.
Самці австралійського морського лева досягають довжини 2,5 метри і важать близько 300 кг. Самки набагато менші, їх параметри становлять лише 1,8 метри і 100 кг. Також обидві статі сильно відрізняються одна від одної за кольором: самці темно-коричневого кольору, у той час як у самок шерсть срібно-сіра або світло-коричнева і нижня частина тіла дещо світліша, ніж верхня.
Колонії цих звірів зустрічаються вздовж західного і південного узбережжя Австралії. Часто вони мешкають на невеликих незаселених островах поблизу від узбережжя. Однак це лише невелика частина їхнього колишнього ареалу, який в XIX столітті доходив до Тасманії та Нового Південного Уельсу. Австралійські морські леви майже не мігрують і залишаються поблизу своїх колоній навіть поза шлюбним періодом. Найбільше коли-небудь зареєстроване віддалення австралійського морського лева від колонії становило 300 км.
Австралійські морські леви не відрізняються шлюбною поведінкою від інших видів вухатих тюленів. Самці досягають узбережжя перед самками і в важких боях один з одним змагаються за найкращі території. Слабші самці таким чином витісняються на край колонії. Коли прибувають самки, місце їхнього виходу на берег вирішує, до гарему якого самця вони будуть належати. У колоніях постійно панує занепокоєння, що викликається молодими самцями, які намагаються використовувати моменти неуважності зрілих самців, щоб спаровуватися з самками на його території. До того ж зрілі самці постійно зайняті тим, щоб перешкодити самкам залишити свій ареал. Для цього вони іноді переслідують самку навіть у сусідні ареали, що призводить до нових боїв з тамтешнім господарем. Австралійські морські леви відрізняються досить високим рівнем агресивності, який окрім них можна спостерігати тільки у південного морського лева.
У порівнянні з іншими тюленями австралійського узбережжя, такими як капський морський котик та новозеландський морський котик, австралійський морський лев є досить рідкісним видом. Їх загальна кількість оцінюється всього в 12 тисяч особин. І хоча він ніколи не був таким численним видом, як обидва вищеназвані, раніше він був поширений набагато ширше і рясніше.
Sư tử biển Úc (danh pháp khoa học: Neophoca cinerea) là một loài động vật có vú trong họ Otariidae, bộ Ăn thịt. Loài này được Péron mô tả năm 1816,[2] và là loài duy nhất trong chi Neophoca.
Loài này chỉ đặc hữu Australia. Đây là đơn loài trong chi Neophoca. Loài sư tử biển này phân bố rải rác khắp quần đảo Houtman Arbrolhos (28°N, 114°Đ.) Ở Tây Úc và quần đảo Pages (35°46'N, 138°18'Đ) ở Nam Úc. Với một dân số ước tính khoảng 14.730 cá thể, Đạo luật bảo tồn động vật hoang dã của Tây Australia (1950) đã liệt kê chúng là "cần được bảo vệ đặc biệt". Tình trạng bảo tồn đối với loài này được liệt kê như là nguy cơ tuyệt chủng.
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Bài viết về các loài trong bộ thú ăn thịt này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn. Sư tử biển Úc (danh pháp khoa học: Neophoca cinerea) là một loài động vật có vú trong họ Otariidae, bộ Ăn thịt. Loài này được Péron mô tả năm 1816, và là loài duy nhất trong chi Neophoca.
Loài này chỉ đặc hữu Australia. Đây là đơn loài trong chi Neophoca. Loài sư tử biển này phân bố rải rác khắp quần đảo Houtman Arbrolhos (28°N, 114°Đ.) Ở Tây Úc và quần đảo Pages (35°46'N, 138°18'Đ) ở Nam Úc. Với một dân số ước tính khoảng 14.730 cá thể, Đạo luật bảo tồn động vật hoang dã của Tây Australia (1950) đã liệt kê chúng là "cần được bảo vệ đặc biệt". Tình trạng bảo tồn đối với loài này được liệt kê như là nguy cơ tuyệt chủng.
Австралийский морской лев, или белошапочный морской лев[1] (лат. Neophoca cinerea) — крупный представитель семейства ушастых тюленей, обитающий на южном и западном побережье Австралии.
Самцы австралийского морского льва достигают длины 2,5 метра и весят около 300 кг. Самки намного меньше и их параметры составляют лишь 1,8 метра и 100 кг. Также оба пола сильно отличаются друг от друга по цвету: самцы тёмно-коричневого цвета, в то время как у самок шерсть серебряно-серая или светло-коричневая и нижняя часть тела несколько светлее, чем верхняя.
Колонии этих зверей встречаются вдоль западного и южного побережья Австралии. Часто они обитают на небольших необитаемых островах вблизи от побережья. Однако это лишь небольшая часть их прежнего ареала, который в XIX веке доходил до Тасмании и Нового Южного Уэльса. Австралийские морские львы почти не мигрируют и остаются вблизи своих колоний даже вне брачных периодов. Самое большое когда-либо зарегистрированное отдаление австралийского морского льва от колонии составляло 300 км.
В своём поведении, относящемуся к спариванию, австралийские морские львы не отличаются от других видов ушастых тюленей. Самцы достигают побережья перед самками и в отчаянных боях друг с другом соперничают за лучшие территории. Более слабые самцы таким образом вытесняются на край колонии. Когда прибывают самки, место их выхода на берег решает, к гарему какого самца они будут относиться. В колониях постоянно царит беспокойство, вызываемое молодыми самцами, которые стараются использовать моменты невнимательности зрелых самцов, чтобы спариваться с самками на его территории. К тому же зрелые самцы постоянно заняты тем, чтобы помешать самкам покинуть свой участок. Для этого они иногда преследуют самку даже на соседских участках, что приводит к дракам с их хозяевами. Австралийские морские львы отличаются довольно высоким уровнем агрессивности, который кроме них можно наблюдать только у южного морского льва.
По сравнению с другими тюленями австралийского побережья, такими как капский морской котик и новозеландский морской котик, австралийский морской лев является довольно редким видом. Их общее число оценивается всего в 12 тысяч особей. И хотя он никогда не был таким многочисленным видом, как оба вышеназванных, ранее он был распространён намного шире и обильнее.
Австралийский морской лев, или белошапочный морской лев (лат. Neophoca cinerea) — крупный представитель семейства ушастых тюленей, обитающий на южном и западном побережье Австралии.
澳洲海獅（學名：Neophoca cinerea，英語：Australian sea lion）是一種只生活在澳大利亞南部和西部海岸的海獅。新海獅屬現存的唯一一種生物。澳大利亞海獅屬於鰭足亞目，與海獅科的其他海獅及海狗極其相似。
澳洲海獅的繁殖週期在鰭足亞目中算是不尋常的。其週期為18個月，而且在不同的群體之間並不同步。繁殖季節可以持續5至7個月，袋鼠島的海豹灣有超過9個月的記錄。
繁殖季的雄性澳洲海獅並沒有固定的領地，它們通過打鬥來建立內部等級，處於統治地位的雄性會守衛屬於自己的雌性交配權。在生育幼崽之後，雌性澳洲海獅會選擇守衛新的幼崽，而趕走上一次產下的幼崽。[2]
1972年澳大利亞國家公園和野生動物法案簽署後禁止了捕獵澳洲海獅，其現存大約14730頭[3]。
澳洲海獅（學名：Neophoca cinerea，英語：Australian sea lion）是一種只生活在澳大利亞南部和西部海岸的海獅。新海獅屬現存的唯一一種生物。澳大利亞海獅屬於鰭足亞目，與海獅科的其他海獅及海狗極其相似。
오스트레일리아바다사자 (Neophoca cinerea)는 오스트레일리아에서만 발견되는 기각류 바다사자의 일종이다.[2] 오스트레일리아바다사자속(Neophoca)의 유일종이다. 오스트레일리아 서부 호우트만 아브롤류스 제도(28°S., 114°E.)와 오스트레일리아 남부의 더 페이지스 제도(35°46’S., 138°18’E)에 분포하는 희귀종이다. 1950년 웨스턴 오스트레일리아 야생동물보호법은 개체수를 약 14,730여 마리로 추산하고, "특별 보호가 필요한" 동물로 지정했다. 국제자연보전연맹(IUCN)에 의해 멸종위기종(EN, Endangered species)으로 지정되어 있다. 이 기각류는 특히, 다른 기각류가 12개월 번식 주기를 갖는 것과 달리 5개월 번식주기와 17~18개월 비계절성 번식주기 사이의 다양하고, 특이한 번식 주기를 갖는 것으로 알려져 있다.[2]
다음은 물개과의 계통 분류이다.[3]
물개과 북방물개속 큰바다사자속 바다사자속오스트레일리아바다사자 (Neophoca cinerea)는 오스트레일리아에서만 발견되는 기각류 바다사자의 일종이다. 오스트레일리아바다사자속(Neophoca)의 유일종이다. 오스트레일리아 서부 호우트만 아브롤류스 제도(28°S., 114°E.)와 오스트레일리아 남부의 더 페이지스 제도(35°46’S., 138°18’E)에 분포하는 희귀종이다. 1950년 웨스턴 오스트레일리아 야생동물보호법은 개체수를 약 14,730여 마리로 추산하고, "특별 보호가 필요한" 동물로 지정했다. 국제자연보전연맹(IUCN)에 의해 멸종위기종(EN, Endangered species)으로 지정되어 있다. 이 기각류는 특히, 다른 기각류가 12개월 번식 주기를 갖는 것과 달리 5개월 번식주기와 17~18개월 비계절성 번식주기 사이의 다양하고, 특이한 번식 주기를 갖는 것으로 알려져 있다.
