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Jumat, 13 Januari 2012

MAMALIA AIR

MAMALIA  AIR

Water Mammal yaitu mamalia  yang hidup di laut maupun di air tawar. Contoh hewan ini adalah Sea Lions, The Walrus, Sperm Whale, Beluga Whale, Blue Whale, Manatees, Narwhal, The Platypus, Dolphins, Dugong, Elephant Seal, Northern Fur Seal, Gray seal, Leopard Seal,Sea Otters.

Ciri-ciri mamalia
a.    Mempunyai kelenjar susu yang terletak disisi bawah tubuh (di ketiak). Betina dapat mengeluarkan susu setelah melahirkan. Kelenjar ini seperti kelenjar keringat, jadi diatur oleh hormon. Air susu marine mammal mengandung 40-50% lemak untuk mensupport pertumbuhan bayi-nya agar memiliki lapisan lemak yang cukup.
b.    Melahirkan (viviparous), menyusui.
c.    Bulu, sedikitnya ada dalam satu siklus hidup. Bulu ikan paus hanya beberapa helai di sekitar tenggorokan dan hilang setelah dewasa. Bulu tumbuh dari kantong bulu di dalam kulit yang dilengkapi dengan kelenjar palit yang mengeluarkan minyak sehingga nampak mengkilat. Bulu berperan sebagai termoregulasi (pengatur suhu / memper -tahankan suhu tubuh pada tingkat tertentu).
d.    Jantung terdiri dari 4 bilik
e.    Eritrocit tanpa inti dan bi concaf
f.    Otak relatif besar
g.    Pada rongga dada terdapat iga dan diaphragma.
h.    Marine mammal bernafas dari udara sedangkan hewan laut bernafas dari udara yang terlarut di air.
i.    Suhu tubuh relatif lebih tinggi dari suhu lingkungannya, karena dibantu oleh lapisan lemak dan bulu di tubuhnya.
j.    Mempunyai kemampuan melawan arus (countercurrent exchange) seperti gerakan hauling (menggulung) untuk mengurangi penurunan panas tubuh.

Marine Mammal/ Mamalia laut
Adalah mamalia  yang hidup di laut atau mencari makannya di laut. Merupakan evolusi dari nenek moyang nya yang hidup di daratan kemudian beradaptasi hidup di air. Umumnya besar-besar (charismatic megafauna), bentuk tubuhnya hydrodynamis, ekstremitas nya termodifikasi untuk bergerak di air dan mengalami adaptasi untuk berbagai suhu (termoregulasi) karena beberapa species dapat beradaptasi untuk berbagai tingkat suhu karena memiliki lapisan lemak yang tebal (tick layer blubber) untuk mencegah hilangnya panas tubuh.
Hewan laut yang beradaptasi penuh hidup di air adalah ordo Cetacea dan Sirenia yang seluruh siklus hidupnya di dalam air. Sedangkan ordo lainnya memanfaatkan sebagian waktunya di daratan. Beruang kutub sebagian besar hidupnya dimanfaatkan di laut meskipun lautnya beku. sangat pandai berenang di laut terbuka dalam satu hari dapat mencapai 74 km, sehingga beruang kutub oleh ilmuwan digolongkan dalam marine mammal.
Beberapa jenis mamalia ini menuju kepunahan, bahkan banyak yang saat ini sudah punah. karena dulunya di eksploitasi  untuk diambil lemak, daging, taring dan bulunya. Sehingga saat ini banyak dilindungi. Mamalia air terdapatasi untuk berenang memanfaatkan sirip-nya  untuk bergerak. Ikan juga berenang menggunakan sirip-2nya. Ikan umumnya mempunyai sirip caudal yang tegak sedangkan marine mamalia mempunyai sirip caudal yang horisontal.
Kelompok marine mamalia
Diperkirakan terdapat 120 species yang dikelompokkan menjadi 3 ordo.
1.    Sirenia / sirenians : Famili Trichechidae : manatee (3 species)
                                      Famili Dugongidae / dugong (1 species)

2.    Cetacea (, dolphins dan Lumba-lumba / porpoises)
Sub ordo Mysticeti :  Baleen whales/  Paus ( 14 atau 15 species)
       Sub ordo Odontoceti : Toothed whales (± 73 species)

3.    Carnivora
Super famili : Pinnipedia (berasal dari nenek moyang ber gigi taring)
        Famili Phocidae : true seals / anjing laut (± 20 species)
                 Famili Otariidae : eared seals (± 16 species)
        Famili Odobenidae : walrus  (1 species)

Famili Mustelidae : sea otter (Enhydra lutris)
                      Marine otter (Lontra felina)

Famili Ursidae : Polar bear (beruang kutub) Ursus maritimus

Sea Lions

                                The Walrus













Caribbean Monk Seal
Declared extinct June 9th, 2008 (not seen since 1952)


The Manatee

















Platypus
Platipus hidup gua-gua ditepi sungai juga dapat dilihat didekat danau alpine di Tasmania (selatan Ausii) & di Australia timur (tropical rain forest river.
In the past, platypuses lived in South Australia but they no longer live there. There are platypus on Kangaroo Island, but these were brought to the island in an attempt to save animals people thought might become extinct.[5] There are very few if any platypuses left in most the Murray-Darling Basin.[6] The water there is no good because people used it to grow plants, and cleared the trees from the land. It is strange that the platypus does not live in some healthy rivers. It does live in some less healthy coastal rivers, for example the Maribyrnong River in Victoria.
Platypus are difficult to see in the wild. They dislike areas with people, spend most of their time underground or under water, and sleep during the day. At Eungella National Park in Queensland, there are spots on the river with viewing areas where wild platypus can usually be seen each evening.[4]








Reproduksi nya bertelur The eggs develop in utero for about 28 days with only about 10 days of external incubation (in contrast to a chicken egg, which spends about 1 day in tract and 21 days externally).[34] After laying her eggs, the female curls around them. The incubation period is separated into three parts. In the first, the embryo has no functional organs and relies on the yolk sac for sustenance. The yolk is absorbed by the developing young.[44] During the second, the digits develop, and in the last, the egg tooth appears.[45]
The newly hatched young are vulnerable, blind, and hairless, and are fed by the mother's milk. Although possessing mammary glands, the Platypus lacks teats. Instead, milk is released through pores in the skin. There are grooves on her abdomen that form pools of milk, allowing the young to lap it up.[3][33] After they hatch, the offspring are suckled for three to four months. During incubation and weaning, the mother initially only leaves the burrow for short periods to forage. When doing so, she creates a number of thin soil plugs along the length of burrow possibly to protect the young from predators; pushing past these on her return forces water from her fur and allows the burrow to remain dry.[46] After about five weeks, the mother begins to spend more time away from her young and at around four months the young emerge from the burrow.[33] A platypus is born with teeth, but these drop out at a very early age, leaving the horny plates they grind their food with.[47]
The fossil is thought to be about 110 million years old, which means that the Platypus-like animal was alive during the Cretaceous period, making it the oldest mammal fossil found in Australia. Monotrematum sudamericanum, another fossil relative of the Platypus, has been found in Argentina, indicating that monotremes were present in the supercontinent of Gondwana when the continents of South America and Australia were joined via Antarctica (up to about 167 million years ago).[16][51]
Dolphin
For other uses, see Dolphin (disambiguation)



  










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Bottlenose Dolphin
breaching in the bow wave of a boat







Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in seventeen genera. They vary in size from 1.2 m (4 ft) and 40 kg (90 lb) (Maui's Dolphin), up to 9.5 m (30 ft) and 10 tonnes (9.8 LT; 11 ST) (the Orca or Killer Whale). They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating fish and squid. The family Delphinidae is the largest in the Cetacea, and relatively recent: dolphins evolved about ten million years ago, during the Miocene. Dolphins are considered to be amongst the most intelligent of animals and their often friendly appearance and seemingly playful attitude have made them popular in human culture.

Common Dolphin
Spotted Dolphin


  

          
Commerson's Dolphin
                                Dusky Dolphin


  








Killer Whales, a lso known as Orcas


 Origin of the name
The name is originally from Ancient Greek δελφίς (delphís; "dolphin"), which was related to the Greek δελφύς (delphys; "womb"). The animal's name can therefore be interpreted as meaning "a 'fish' with a womb".[1] The name was transmitted via the Latin delphinus, Middle Latin dolfinus and the Old French daulphin, which reintroduced the ph into the word.
The word is used in a few different ways. It can mean:
•    Any member of the family Delphinidae (oceanic dolphins),
•    Any member of the families Delphinidae and Platanistoidea (oceanic and river dolphins),
•    Any member of the suborder Odontoceti (toothed whales; these include the above families and some others),
•    Used casually as a synonym for Bottlenose Dolphin, the most common and familiar species of dolphin.
In this article, the second definition is used. Porpoises (suborder Odontoceti, family Phocoenidae) are thus not dolphins in this sense. Orcas and some closely related species belong to the Delphinidae family and therefore qualify as dolphins, even though they are called whales in common language. A group of dolphins can be called a "school" or a "pod". Male dolphins are called "bulls", females "cows" and young dolphins are called "calves".[2]
The Boto, or Amazon River Dolphin
•    Suborder Odontoceti, toothed whales
o    Family Delphinidae, oceanic dolphins
•    Genus Delphinus
•    Long-Beaked Common Dolphin, Delphinus capensis
•    Short-Beaked Common Dolphin, Delphinus delphis
•    Genus Tursiops
•    Common Bottlenose Dolphin, Tursiops truncatus
•    Indo-Pacific Bottlenose Dolphin, Tursiops aduncus
•    Genus Lissodelphis
•    Northern Rightwhale Dolphin, Lissodelphis borealis
•    Southern Rightwhale Dolphin, Lissiodelphis peronii
•    Genus Sotalia
•    Tucuxi, Sotalia fluviatilis
•    Costero, Sotalia guianensis
•    Genus Sousa
•    Indo-Pacific Hump-backed Dolphin, Sousa chinensis
•    Chinese White Dolphin (the Chinese variant), Sousa chinensis chinensis
•    Atlantic Humpbacked Dolphin, Sousa teuszii
•    Genus Stenella
•    Atlantic Spotted Dolphin, Stenella frontalis
•    Clymene Dolphin, Stenella clymene
•    Pantropical Spotted Dolphin, Stenella attenuata
•    Spinner Dolphin, Stenella longirostris
•    Striped Dolphin, Stenella coeruleoalba
•    Genus Steno
•    Rough-Toothed Dolphin, Steno bredanensis
•    Genus Cephalorynchus
•    Chilean Dolphin, Cephalorhynchus eutropia
•    Commerson's Dolphin, Cephalorhynchus commersonii
•    Heaviside's Dolphin, Cephalorhynchus heavisidii
•    Hector's Dolphin, Cephalorhynchus hectori
•    Genus Grampus
•    Risso's Dolphin, Grampus griseus
•    Genus Lagenodelphis
•    Fraser's Dolphin, Lagenodelphis hosei
•    Genus Lagenorhyncus
•    Atlantic White-Sided Dolphin, Lagenorhynchus acutus
•    Dusky Dolphin, Lagenorhynchus obscurus
•    Hourglass Dolphin, Lagenorhynchus cruciger
•    Pacific White-Sided Dolphin, Lagenorhynchus obliquidens
•    Peale's Dolphin, Lagenorhynchus australis
•    White-Beaked Dolphin, Lagenorhynchus albirostris
•    Genus Orcaella
•    Australian Snubfin Dolphin, Orcaella heinsohni
•    Irrawaddy Dolphin, Orcaella brevirostris
•    Genus Peponocephala
•    Melon-headed Whale, Peponocephala electra
•    Genus Orcinus
•    Killer Whale (Orca), Orcinus orca
•    Genus Feresa
•    Pygmy Killer Whale, Feresa attenuata
•    Genus Pseudorca
•    False Killer Whale, Pseudorca crassidens
•    Genus Globicephala
•    Long-finned Pilot Whale, Globicephala melas
•    Short-finned Pilot Whale, Globicephala macrorhynchus
•    Genus †Australodelphis
•    †Australodelphis mirus
o    Superfamily Platanistoidea
•    Family Platanistidae
•    Ganges and Indus River Dolphin, Platanista gangetica with two subspecies
•    Ganges River Dolphin (or Susu), Platanista gangetica gangetica
•    Indus River Dolphin (or Bhulan), Platanista gangetica minor
•    Family Iniidae
•    Amazon River Dolphin (or Boto), Inia geoffrensis
•    Family Lipotidae
•    Chinese River Dolphin (or Baiji), Lipotes vexillifer (possibly extinct, since December 2006)
•    Family Pontoporiidae
•    La Plata Dolphin (or Franciscana), Pontoporia blainvillei
Six species in the family Delphinidae are commonly called "whales" but are strictly speaking dolphins. They are sometimes called blackfish.
•    Melon-headed Whale, Peponocephala electra
•    Killer Whale (Orca), Orcinus orca
•    Pygmy Killer Whale, Feresa attenuata
   Wolphin Kawili'Kai at the Sea Life Park in Hawaii.
•    False Killer Whale, Psudorca crassidens
•    Long-finned Pilot Whale, Globicephala melas
•    Short-finned Pilot Whale, Globicephala macrorhynchus

Hybrid dolphins
In 1933, three strange dolphins were beached off the Irish coast; these appeared to be hybrids between Risso's Dolphin and the Bottlenose Dolphin.[3] This mating has since been repeated in captivity and a hybrid calf was born. In captivity, a Bottlenose Dolphin and a Rough-toothed Dolphin produced hybrid offspring.[4] A Common-Bottlenose hybrid lives at SeaWorld California [5] Various other dolphin hybrids live in captivity around the world or have been reported in the wild, such as a Bottlenose-Atlantic Spotted hybrid.[6] The best known hybrid however is the Wolphin, a False Killer Whale-Bottlenose Dolphin hybrid. The Wolphin is a fertile hybrid, and two such Wolphins currently live at the Sea Life Park in Hawaii, the first having been born in 1985 from a male False Killer Whale and a female Bottlenose. Wolphins have also been observed in the wild.[7]



  
Dugong

Not to be confused with Dewgong or Dougong
Dugong        
Fossil range: Early Eocene–Recent


Conservation status
Binomial name

Vulnerable (IUCN 3.1)[2]
Dugong dugon  (Müller, 1776)

Scientific classification
Natural range of D. dugon.
Kingdom:    Animalia
Subfamily:    Dugonginae
Simpson, 1932
Phylum:    Chordata
  
Class:    Mammalia
Genus:    Dugong
Lacépède, 1799
Order:    Sirenia
Species:    D. dugon
Family:    Dugongidae
Gray, 1821
  
  










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