When it comes to marsupials, the first country we think of is Australia, such as kangaroo , thyrofolk , koalas , etc. These marsupials are all concentrated in Australia, which gives us the illusion that marsupials are unique to Australia.
Of course, this is just our illusion. The reason is that Australia has the most marsupials. In fact, whether in the past or at present, marsupials are not only distributed in Australia, but also in other countries of , Oceania, , where Australia is located, the Americas and even Asia. The distribution of marsupials is actually closely related to their origin in our country. Let’s take a closer look.
One of the representative species of marsupials Red Kangaroo
Marsupials are not exclusive to Australia
Australia Although we often call it Australia, it is not a continent, because the continent it is located in is Oceania, it also contains New Zealand and 12 independent countries. In most countries, there are actually marsupials on the land of the land, so strictly speaking, marsupials should be mainly concentrated in Oceania.
In addition to Oceania, the Americas has the most marsupial animals. They together form the order of the American Marsupials, including Possum and . Although there is only one family under the Possum 1 ( Possum ), there are a total of 67 existing species under this family. They are almost all over South America and are even distributed in North America ( North American Possum ).
mentions possum . It has two more interesting things. The first is that they like to carry their cubs on their backs. The second is that they like to pretend to be dead when they encounter danger. When they pretend to be dead, in addition to stretching their legs and staring, they also stick out their tongues, which is no different from the animals that really die, and their acting skills are online.
There are 6 animals in the order of Shrew Possum. They are also a unique class of marsupials in South America. Unlike Shrew Possum, the animals under the order of Shrew Possum are very small in size, similar to shrews, with small eyes and slender mouths. They are a nocturnal insectivorous animal, and their parenting bag has been highly degraded.
shrew possum
In addition to the Americas, we actually have wild marsupials in Asia, and there are more than one type, there are as many as 17 species in total. They are in 3 families: 吉生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生生�
As for the family marsupial family, it is the largest number and species of marsupial family in Asia, including more than 10 different species such as Island Bagli, Sudao Bagli, Gebe Bagli, and Gray Bagli, etc. The only species of Kangaroo family in Asia is the gray tree kangaroo, which is a type of kangaroo that lives mainly on tall trees. The hair on the whole body is mainly gray, hence the name. They are mainly distributed on the island of Yapeng, Indonesia.
Summary : There are about 240 existing marsupials, while there are about 84 species in the Americas and Asia, and the rest are all distributed in Oceania. Therefore, marsupials are not unique to Oceania, but their main distribution areas are indeed concentrated in Oceania .
Evolutionary Route of Marsupials
The current distribution pattern of marsupials once made scientists think that Australia was the birthplace of marsupials. After dinosaurs became extinct in , they took advantage of the fact that various continents were still connected to South America, and then reached America, and as far as Asia.
However, this statement was quickly overturned with the continuous unearth of fossils, because the fossils of primitive marsupials that scientists discovered in the Cretaceous were basically found in the Americas and Asia, which means that marsupials in Australia, including Oceania, actually later evolved here.
Later, scientists discovered the earliest marsupial fossil triangular beast in North America. It lived about 11,000 years ago. At this time, the evolutionary route of marsupial animals was rewritten. Some scientists believe that marsupial animals evolved in North America, then entered South America, and then entered Oceania through South America, and then entered Asia from Oceania.
Until 2003, scientists in my country discovered the earliest marsupial fossils in Northeastern region. It is Chinese marsupials (sinodelphys) . This is the most primitive marsupial discovered so far. It lived about 125 million years ago, and it took about 15 million years to appear before the original marsupial marsupials discovered in North America.
The size of Chinese marsupials is similar to that of mice, with an average length of about 15 cm and an average weight of 30 grams. They are a highly arboreal insectivorous marsupials.
This means that my country is the earliest origin of marsupials, and placentals and marsupials have evolved separately at least 125 million years ago. At this time, the route of marsupials is to spread from my country to some Asian regions, especially Southeast Asia, and part of them enter North America, and then South America, and finally Oceania.
However, due to various reasons, as the origin of Asia, there are fewer and fewer marsupials. Instead, the ultimate place where marsupials migrate is flourishing in Oceania, which is why the current distribution pattern of marsupials is now available.
Why do marsupials form their current distribution pattern?
From the perspective of the migration and evolution of marsupials, Asia should have the most marsupials, followed by the Americas and finally Oceania. Now this order is just reversed. The reason is nothing more than one: higher-level real beast mammals rise.
The marsupials used to be very prosperous, and I don’t want to see few carnivores that are so good now, such as the sabre-toothed tiger , sabre lion , etc. These animals are very powerful even among carnivores today.
bag lion recovery image
However, even if these animals are very powerful, they are not as good as carnivorous mammals that emerged later, such as felines, canines and bear family animals. First of all, the cubs of marsupials " premature birth " need to stay in the parenting bag for a long time, and emerging carnivorous animals can keep their cubs in a safe place without distractions, which makes it possible for both carnivorous and herbivorous marsupials to become prey as long as they appear in the area where new large carnivorous animals appear.
. The emerging mammals happen to be very prosperous in Asia and North America, so the original marsupials are suppressed.
But Oceania is different. As early as 50 million years ago, the split of Vanadian prefecture led to the separation of Oceania and other continents. Although carnivorous marsupials have also appeared in Oceania, thyros are too small and their hunting ability is very limited, which will not affect the overall evolution of marsupials. Moreover, thyros are later artificially extinct, which makes Oceania, especially Australia, a paradise for marsupials.
Thailand
If this happens, why are there still marsupials in the Americas and Asia still surviving? The answer is simple, these animals have their own "little tricks" to survive.
Let’s first look at the marsupials in the Americas. There are two main reasons for their survival in competition: the first is that they are small in size. If they are small in size, they will not be the priority prey of large carnivores; the second is arboreals. Possums like to move on trees very much, and their tails can hook branches like monkeys.
Therefore, the size is small and the whole is on the tree, so carnivores will certainly not regard them as their main prey.
Let’s take a look at the marsupials in Asia. There are two main reasons why Asian marsupials can survive: the first is islandization. Most marsupials in Asia live on some small islands in Southeast Asia. These small islands are indeed threatened by carnivores; the second is also arboreals. Most Asian marsupials are active in trees, which makes them less threatened.
Bag cats living on the Malay Islands
Summary
Marsupials are not only animals unique to Australia (even Oceania), nor are they even the origin of marsupials (Asia, currently in the northeast of my country), but later came here through long-term migration.
However, as an evolutionary branch of mammals, marsupials have much worse survival and combat effectiveness than real beast mammals. Therefore, when these animals rose, most of the marsupials in Asia and America disappeared, leaving only Oceania, which was disconnected from other continents early, is more suitable for the survival and evolution of marsupials, so the current situation is formed.
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