There are 150 kinds of marsupials in the world. Most of them grow in Australia. The famous ones are: kangaroo, koala, bag and so on. Living marsupials are distributed in the grasslands of Oceania and South America, but they may be distributed in most parts of the world in the late Cretaceous and early Tertiary. They are a group of ancient mammals. With the rise of higher mammals-real mammals, they are at a disadvantage in the competition for survival, especially becoming the prey of carnivores, making them extinct in Asia, Europe and Africa. Prior to this, Oceania had been separated from other continents, forming a "Xanadu", isolated between the Pacific Ocean and the Indian Ocean. Not only did higher mammals such as carnivores not invade, but the climate and environment did not change much. This has enabled marsupials to survive to this day, and because they have adapted to various lifestyles, they have developed various ecological groups similar to higher mammals, such as marsupials and marsupials whose lifestyles are similar to those of carnivores such as wolves and ferrets; Kangaroos whose lifestyles are similar to those of herbivores such as deer, sheep and antelope; Lifestyles are similar to marmots, squirrels, rabbits and other rodents or rabbits, such as wombats, minks and marsupials. Therefore, Oceania has become an important area to study the adaptation of animals to radiation and evolutionary convergence, and is called "Living Fossil Museum". It should be noted that the first marsupial described by zoologists was not in Oceania, but in Brazil in South America. In addition to Oceania, marsupials are also found in some parts of America, with more than 70 species. How to explain their origin? Some people think that it is because of some accidental opportunity that the ancestors of smaller marsupials who lived in arboreal life crossed the ocean to America with the help of trunks or other objects of big trees. Because there are relatively few natural enemies here, they survived and multiplied. However, whether this "drift" theory is correct remains to be verified or improved. There are about 237 species of marsupials, belonging to more than ten families, such as opossum, weasel, kangaroo, marsupial, neokangaroo, female, wombat, kangaroo and so on. Among them, the distribution of new kangaroos is limited to parts of South America, opossums are distributed in parts of South America and North America, and the rest are distributed in Oceania. Among marsupials, kangaroo is the most famous and lovely rare animal, and its image appears on the national emblem of Australia, so that it has almost become synonymous with Australia. There is an interesting story about the origin of its English name. It is said that in the18th century, an English navigator led his fleet to Oceania for the first time. When they saw this monster with short forelegs and long hind legs, they were very surprised and asked the local natives what to call this animal. The natives answered, "Kang Lu". Thus, "Kang Lu" became the English name of kangaroo, which is still used today. But later people realized that "Kangaru" originally meant "don't know" in the local dialect. Kangaroos are typical marsupials, with about 52 species, distributed in Australia, Tasmania, New Guinea and several nearby islands, and introduced to New Zealand. Most species are terrestrial, and only kangaroo is arboreal. The gray kangaroo living in the forest and bush and red kangaroo living in the grassland are the largest marsupials and the representative species of kangaroos. Their body length is about 1.5m, their tail length is about 1.2m, and their weight is 70-90kg. They look strange, so if people like them. They have small heads, big ears and big eyes. Adapted to the jumping lifestyle, the forelimbs are short and thin and can be used to grab food. The hind legs are strong and the toes are close together. One step can jump 5 meters, and the speed can reach 40-65 kilometers per hour. When the tail grows up, it is the supporting organ when perching and the balancer when jumping. Stay in the daytime and go out at night, hiding in grass nests or shallow holes during the day. Like to gather small groups, mainly plant food. It breeds once a year, and each fetus gives birth to 1-2 offspring, with a gestation period of about 33 days. Since Europeans immigrated to Australia in 1788, many new animals have been introduced, and the original living conditions of many marsupials have been destroyed. Due to various natural and social factors, six kangaroos have become extinct. Due to the intensification of human economic activities, it has brought many adverse effects on the survival of marsupials in the future. At present, about 17 species of marsupials are listed in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, and 7 species are listed in Appendix II. If the living marsupials are not strictly protected, this group, which is very unique and has important academic significance in the evolution of mammals, will eventually decrease or become extinct rapidly with the further increase of human economic activities. An opossum marsupial is an animal raised by its mother in her pouch. Most marsupials live in Australia and neighboring islands. But opossums are special. Although they are marsupials, they live in North and South America. The most famous is the Virginia opossum. At night, they come to the ground to look for food, but if they feel dangerous, they will quickly climb the tree. Animals are good at this. Young rats can wrap their tails around branches and swing upside down. At birth, the mouse will slowly climb into the pouch through its mother's body hair. The nipple in the female rat's bag is enough to feed 13 young rats. When an opossum is chased by a dog or hyena, it will howl or scream. But if caught, it will play dead and become completely soft. At this time, many enemies will enhance their interest in eating it, because they generally don't like to eat dead animals. The opossum has a toe opposite to the other toes on its hind foot. In other words, this toe can be folded and close to the sole of the foot, just as our fingers can be folded into palms. In this way, it can catch the branch. After the baby opossum leaves its mother's pouch, it will lie on its back while her mother is looking for food. Mother mice may be clumsy because they have too many children on their backs. ◆ Tasmanian tiger The English name of the Tasmanian Tiger, Thylacine Harris, has been widely distributed in the Australian mainland and nearby islands. After European immigrants settled in Australia, the marsupial wolf on the Australian mainland became extinct, and it was only distributed in Tasmania in southern Australia. Some people think that wild populations are extinct. Body like a dog, head like a wolf. Shoulder height is 600 mm, body length is 750 mm, tail length is 530 mm, coat color is light gray or yellowish brown, and there are 14- 18 black band spots on the back. Hair is short, dense and very hard. The mouth is very long. Five toes on the front foot and four toes on the back foot. Habitat in open woodlands and grasslands. Go hunting at night and live in gravel during the day. Many prey on kangaroos, small mammals and birds alone or in families. Because its mouth is very cracked, predators often bite the skull of their prey. Mating in summer produces 3-4 offspring per child. Cubs can move alone after being fed in their mother's pouch for 3 months, but they will still stay with their mother for about 9 months. This is an indescribable and wonderful animal. Judging from its head and teeth, it is a wolf. However, its body is striped like a tiger. It can run on four legs like a hyena. You can also jump on your hind legs like a kangaroo. It is a marsupial like a kangaroo. This animal has the characteristics of other kinds of animals, but it has some special features. Known as Tasmanian Wolf, Zebra Wolf, Tasmanian Tiger and so on. Marsupials live in sparse forests or grasslands. However, when settlers come to the land where they live, they will hide in the depths of the forest. This carnivorous marsupial is from beginning to end 1.5 to 1.8 meters long. Shoulder height 60 cm. There is a bag on the stomach, and you can put a baby kangaroo like a kangaroo. There are twelve to twenty patterns on the back. Jaw bone is divided into two parts like a snake. They will bite off the head of a hunting dog. At night, they act alone, often targeting kangaroos, wallabies or flightless birds. It doesn't run fast, but it will chase after it until its prey is exhausted. They often bite the head of their prey to end their lives. Since the arrival of Tasmanian immigrants, the survival of the marsupial wolf has been in crisis. A large number of domestic animals-sheep have been hurt by dogs. Moreover, people mistakenly think it is a marsupial, because both dogs and marsupials suck the blood of sheep. 1888, the government offered a reward to those who killed marsupials. In the next twenty years, 2,268 marsupials were arrested and killed. This is also valuable information to record the number of marsupials. The last marsupial wolf died in 1933. People found murals painted by ancient residents 10 thousand years ago on rocks in Australia, from which we know that marsupials once lived in this ancient land a long time ago. Surprisingly, there is a wombat reserve in Tasmania. Does this mean that it is a kind of psychological compensation? In a word, such a precious animal-the marsupial wolf is extinct. Despite living with an ancient Australian resident for more than 10 thousand years. However, with the discovery of new lands by human beings one by one, marsupials finally disappeared from the earth forever in a blink of an eye.