We all know about the kangaroo as an animal? Its biggest feature is not called "rat", nor is it a high jump, but a pocket on the stomach. Kangaroos are unique mammals in Australia, but when it comes to mammals here, it is not just kangaroos, in fact, many animals have a bag naturally growing on their stomachs, but according to statistics, if you did not know the marsupials of Australia before, then when you hear that there is a pocket of things growing on the belly of an animal, it will be very surprising, because we have not heard of such animals a hundred years ago, and we in China and even many parts of the world do not have animals with long pockets.
But in Oceania, there are more than 240 species of marsupial mammals, including possums, possums, possums, possums, kangaroos, possums, wombats and more than ten families. So why is this marsupial only found in Australia and not in the rest of the world? In fact, this is not right! Australia belongs to Oceania, and marsupials are present in Oceania, South America, and some parts of eastern Southeast Asia.
Marsupials belong to mammals, is a subject that is produced early in its appearance, which is characterized by the fact that when the mother conceives the carcass, the uterus will not form a fully developed placenta like other types of mammals, so the carcass will be born prematurely when it is not fully developed, and then the larvae will stay in the mother's nursery bag to suck milk and continue to grow up, and their so-called nursery bag is actually a layer of skin wrapped around the nipple, which can wrap the young animals in it, and the marsupial is named after its pocket-shaped nursery bag.
So how do marsupials form? In fact, they are a relatively primitive mammal, when the dinosaurs suddenly disappeared 65 million years ago, mammals began to rise, one of which is marsupials, they are now Oceania, Africa, Antarctica and Some places in South America reproduce and evolve, but at that time Oceania and South America and Antarctica and Africa were still connected, but about 50 million years ago, these continents began to separate, and gradually appeared in the middle of the vast ocean, As a result, marsupials embarked on the path of isolated evolution.
Paleontologists believe that marsupials may have been all over the world, in the late Cretaceous and early Tertiary periods were once very numerous, but with the rise of higher-level euprotene mammals, marsupials began to be at a disadvantage in survival competition, they lack large carnivorous predators, so most of them became the predators of euphropod carnivorous mammals, and the underdeveloped juvenile mammals are not easy to feed compared to eudeal mammals, and the larvae have a long lactation period and grow slower by sucking milk alone. This gradually led to the extinction of marsupials on continents such as Asia, Europe and Africa. And because Oceania, which has the most marsupials, has been separated from other continents before this, the true mammals have not been able to set foot on the Australian mainland and major islands, which has led to Oceania becoming a "paradise" for marsupial mammals, and this event has made marsupials finally lucky to survive to this day.
Australia is the only continent that exists independently in the ocean, and the isolated ecological environment has also led to the development and evolution of various ecological groups of marsupial mammals similar to other parts of the world, such as thylacines, possums, marsupials and other carnivores such as wolves, ferrets, cats, etc., kangaroos lifestyles are similar to herbivores such as deer, sheep and antelopes, and wombats, possums and kangaroos are similar to rodents such as otters, squirrels, hares, so Australian marsupials are mammals that are very different from other parts of the world However, in terms of biological life forms, it is roughly convergent.