2006-12-10 04:38:01 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Zoology
My understanding is that marsupials evolved all over the world and were once the dominante life form. During this time Australia moved away from the other land masses that it had been attached to. Mammals began to evolve and took the place of marsupials, they are not as efficient at surviving due to gestation being external. However no mammal evolved in Australia so the marsupials did not have to compete with them. The mammals that live there now have been introduced subsequentally.
I think Madagasga has marsupials too (though I'm not sure) for similar reasons.
2006-12-10 04:50:38 · answer #1 · answered by gerrifriend 6 · 0⤊ 0⤋
There are still marsupials around the world, America has the opossum, there is a marsupial mole in Africa...
The reason only Australia has marsupials is because at the time more advanced mammals (marsupials are mammals) were evolving around the world, Australia was breaking apart to make it's own island. Placenta mammals for some reason out competed the marsupials around the world, becoming more popular than marsupials, but since they never evolved in Australia (and they couldn't swim far enough to get there) the marsupials remained dominant there.
2006-12-10 04:55:06 · answer #2 · answered by George B 3 · 0⤊ 0⤋
according to theory, when the supercontinent of Pangea broke off. All of these types of animals were there. When they got to where they are, the animals then evolved and formed pouches to protect their young from harm. They evolved that way because of the environment
2006-12-10 07:41:58 · answer #3 · answered by Brian Byrd 3 · 0⤊ 0⤋