why do almost all australian mammals have pouches?

Question

ive been reading up on them and WOW they all doo...whats up with that?

Answer 1

Yes. They are called MAESUPIALS.They were once widespread over the earth, but were displaced in most regions as the more successful placental mammals evolved. The Australian region, which has been isolated from contact with other regions since the Cretaceous period, had almost no native placental mammals, and the marsupials were able to continue their evolution there without competition. They underwent an adaptive radiation in Australia comparable to that of placental mammals in the rest of the world, evolving many forms that superficially resemble various placental mammals and fill the same ecological niches.

Marsupial, member of the order Marsupialia, or pouched mammals. With the exception of the New World opossums and an obscure S American family (Caenolestidae), marsupials are now found only in Australia, Tasmania, New Guinea, and a few adjacent islands. They are generally distinguished from placental mammals by the absence of a placenta connecting the embryo with its mother, although in a few forms the female has a rudimentary placenta that functions for a short time. The embryo is nourished during its brief gestation by a fluid secreted by the mother's uterus. The young are born in a very undeveloped state; at birth the great gray kangaroo is about 1 in. (2.5 cm) long and the opossum about 11/2 in. (3.8 cm) long. Immediately after birth the young crawl to the mother's nipples and remain attached to them while continuing their development. As they are still too helpless to suckle, milk is squirted into them by the periodic contraction of muscles over the mother's mammary glands. In nearly all marsupials the female's nipples are covered by a pouch, or marsupium, formed by a fold of abdominal skin. Even after the suckling stage the young return at times to the pouch for shelter and transportation. In many species the young are carried on the mother's back after the suckling stage. In addition to having a less efficient reproductive system than the placental mammals, marsupials are of generally lower intelligence.

These are animals known as Tasmanian wolves, marsupial moles, marsupial mice, and native cats, which live very much like the correspondingly named placental mammals and, in many cases, are strikingly similar in appearance. See bandicoot, numbat, phalanger, Tasmanian devil, wombat.-

Answer 2

Almost all of the mammals in Australia are Marsupials, a group of mammals that are characterized by the presence of a pouch. You can find lots of info on-line about marsupials, the evolution of marsupials, and so on.

There are some placental mammals in Australia, but they are invasive species that don't belong there (were carried there by humans either intentionally or not). The origins and evolution of marsupials is definitely interesting!

Answer 3

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yes it is. Marsupial Mammals Marsupials are the group of mammals commonly thought of as pouched mammals (like the wallaby and kangaroo They give live birth, but they do not have long gestation times like placental mammals. Instead, they give birth very early and the young animal, essentially a helpless embryo, climbs from the mother's birth canal to the nipples. There it grabs on with its mouth and continues to develop, often for weeks or months depending on the species. The short gestation time is due to having a yolk-type placenta in the mother marsupial. Placental mammals nourish the developing embryo using the mother's blood supply, allowing longer gestation times. Like other mammals, the marsupials are covered with hair. Mothers nurse their young — a young kangaroo may nurse even when it has grown almost to the mother's size. The only naturally occurring marsupial in the United States is the opossum, Didelphis marsupialis. In the past, however, marsupials were quite common. During the Mesozoic marsupials were very common in North America; more common, in fact, than placental mammals. They persisted here until the mid- to late-Tertiary. In South America and Australia, however, marsupials continued to be an important group of land mammals. Many South American forms are similar to the North American opossum. The marsupials of South America began to go extinct in the late Miocene and Early Pliocene when a land connection with North America formed, allowing placental mammals to cross into South America. In Australia, though, marsupials continue to be very diverse, and are the dominant native mammals. They include kangaroos, koalas (above left), tasmanian devils, wombats (above right), and other typical Australian mammals. Until recently, they also included the marsupial wolf, Thylacinus (below). Like the quagga, the marsupial wolf is now extinct. The last individual was seen in Tasmania in the 1950s. Though marsupials today do not have as many species as do the placental mammals, they are quite structurally diverse. They range from small four-footed forms like the marsupial mole, Notoryctes, to the large two-legged kangaroos. There are several cases of convergent evolution between marsupials and placental mammals, in which the two animals have evolved to fill the same ecological niche in different parts of the world. There are burrowing forms, grazing forms, gliding forms, and even long-snouted ant-eating forms which have evolved independently in the two groups.

Answer 4

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RE:
why do almost all australian mammals have pouches?
ive been reading up on them and WOW they all doo...whats up with that?

Answer 5

Marsupials (animals who bare their young in a pouch) are the only original mammal on the island (besides monotremes). All the placental mammals were brought their by other humans.

Answer 6

Yes they are. I mean, they're not a fish, nor a reptile, nor an amphibian nor a bird from first sight. So that leaves mammal doesn't it? Also, they're a special type of mammal, which are called marsupials.

Answer 7

Don't forget about bats. Australia has bats, and they are placental mammals. It is unknown whether they are native or not to Australia.

Answer 8

I spose it's coz we Aussies love carrying our babies close to our hearts LOL

Answer 9

Are you Australian? Cause i am and i have no idea.lol