China has a vast territory, spanning three temperature zones of tropical, subtropical and temperate zones, of which the temperate zone is the largest and the smallest tropical range, which only exists in the southern part of Hainan Island and Yunnan-Guangdong-Guangdong, and the land area adds up to less than 100,000 square kilometers, but it is a treasure trove of species in China, such as Xishuangbanna, which is known as the kingdom of animals and plants.
A few months ago, 41 wild elephants appeared in the Wild Elephant Valley of Xishuangbanna
The representative species of Xishuangbanna is the Asian elephant, which is the largest extant terrestrial animal in Asia, and the Asian elephant is also the representative animal of Yunnan, and is even printed on the license plate of Yunnan Province. It is generally said that Yunnan Province is the only province in China that has retained the wild elephant population, distributed in Xishuangbanna, Pu'er, Dehong, Lincang and other places, for the national first-class protected animals, only a few hundred, but the number shows an increasing trend.
Wild Asian elephant in Lincang South Rolling River Reserve
But the whole territory of Hainan Island is tropical, with dense tropical rainforest, why are there no wild elephants?
Seeing this, many people may think: "Hainan Island is an island, separated from the mainland by the Qiongzhou Strait, how can there be elephants!" Could it be that elephants can also swim across the sea? ”
If you really think so, it is too superficial. There is an idiom called "mulberry field of the sea", which means that the sea can become a mulberry field, and the mulberry field can also become the sea, describing the world in constant change. Our ancestors all understood the truth, but now many people do not understand it.
When discussing the changes in natural things, we cannot rush to limit our eyes to the current map, so that it is a blinding eye.
▲ A hypothesis of the origin of Hainan Island: Hainan Island and Liangguang are connected together, and began to separate 65 million years ago due to the collision of the Indian plate and the Eurasian plate, and the island was formed about 24 million years ago, during which it rotated 150 degrees, becoming the current Hainan Island.
The history of the earth has changed land very frequently, especially during the Ice Age, when the sea was massively frozen, making the sea level more than 120 meters lower than it is now. The average water depth of the Qiongzhou Strait is only 44 meters, and the maximum depth is only 114 meters, so at that time, the seabed of the Qiongzhou Strait was exposed to the water, becoming a land bridge, and asian elephants living in the Leizhou Peninsula could enter Hainan Island through the land bridge. Later, when temperatures rose and sea levels rose, they were isolated on Hainan Island. The decline in sea level rise has been repeated several times during ice ages.
Fossil evidence has shown that elephants survived in the prehistoric period on Hainan Island, not only elephants, but also tigers, rhinos, orangutans and even giant pandas.
Ruins of Luobi Cave
From 1992 to 1993, 8 fossils of human teeth and some tools were excavated at the Site of Luobi Cave in Sanya, and fossils of 45 species of mammals such as Asian elephants, South China tigers, jackals, leopards, tapirs, bears, and gibbons were also found. According to carbon-14 determination, the luobi cave site is 10,000 years old, proving that many large animals lived on Hainan Island 10,000 years ago.
Dr. Yan Jia'an explained that during the Late Pleistocene ice age, the sea water was heavily frozen, the sea level continued to decline, the Qiongzhou Strait between Hainan Island and the mainland became a land bridge, and some animals climbed to Hainan Island through the Qiongzhou Strait Land Bridge to breed and live. The average width of the Qiongzhou Strait is less than 30 kilometers, and this distance cannot hinder the migration of animals. This conclusion is also confirmed by a large number of pheasant fossils found on Hainan Island, a bird that is not good at flying and can only enter Hainan Island through a land bridge.
In addition, nearly 20 species of mammal fossils have been found in The Xinchong Cave and the Red Forest Quarry in Changjiang County, including saber-toothed elephants, pandas (presumably Pasteur's giant pandas), giant apes, orangutans, rhinos, ancient hyenas, and giant porcupines. The dating of the site was determined by the China Earthquake Administration to be 400,000-600,000 years ago, so as early as 400,000 years ago, giant apes, pandas, saber-toothed elephants, rhinos, orangutans and other animals arrived at Hainan Island through the Qiongzhou Strait Land Bridge.
Hainan Island was far more lively than it is now, with not only elephants, rhinos and pandas, but also tigers, leopards and jackals. But why haven't these animals been preserved? Some of them are naturally extinct, such as the ancient creatures found in Xinchong Cave, which lived too long ago and became extinct due to environmental changes. Some of them have gone extinct due to human activities, such as some of the animals found in the Pen Cave.
Hainan Island is an island with an area of more than 30,000 square kilometers, although it is located in the tropics, lush vegetation and superior natural conditions, but the area is not large, and the increase in the number of human beings is bound to have an impact on the environment. Some scholars have calculated that according to the hundreds of Neolithic sites found on Hainan Island combined with the number of household registrations in the Zhengde Qiongtai Zhi, the population of Hainan Island in the middle and late Neolithic period has exceeded 10,000.
Tens of thousands of people forage on Hainan Island, elephants, rhinos, tapirs, tigers and other large animals will inevitably clash with humans, in front of humans who can already make tools, wild animals have no advantage, there is no way back on the narrow island, can only retreat.
No fossils of the South China tiger have been found at the sites after the Luobi Cave Age, confirming that it disappeared on Hainan Island 10,000 years ago. Asian elephants and tapirs were extinct about before the Han Dynasty, and in 110 BC, Emperor Wu of the Han Dynasty set up Zhuya County and Dan'er County in Hainan, which first included Hainan Island in the territory, and before that, the large animals on Hainan Island were almost extinct. Subsequent developments of Hainan by various dynasties also led to the extinction of some animals.
The diagram is derived from the visualization of the planet
▲ This is based on Wen Rongsheng's "Changes in the Distribution of Rare Wild Animals in China" made of the change in the distribution range of Chinese Asian elephants, once there were Asian elephants in the Central Plains during the warm period, and then with the reduction of China's tropical range has been retreating south.
▲ This is a map of the distribution range of Chinese rhinos, confirming that there was once a rhino distribution on Hainan Island.
Hainan po deer
Today, the only recorded large animals on Hainan Island are black bears, clouded leopards, wild boars, po deer, black-crowned gibbons and pythons, whose ancestors also migrated from Eurasia. But black bears and clouded leopards have not been seen for many years, and po deer are now the signature of Hainan's rare animals.
Don't think it's strange to have large animals on small islands, it is not unusual for ancient large animals to migrate to the islands through land bridges, and elephant fossils are often found on some islands.
Bullied by giant swans, the ancient teeth of the French are only the size of pigs
For example, the French ancient diamond tooth and Monetri ancient diamond tooth elephant in Sicily and Malta in Italy, the Mamora mammoth in Sardinia, Italy, the Cretan mammoth in Crete in Greece, the small mammoth in the Channel Islands in the United States, the Flores sabertooth and the Sonda sabertooth on Flores Island in Indonesia, and the fossils of saber-toothed elephants have also been found in Treasure Island, Japan, the Philippines, Java and Sulawesi.
How the saber-toothed elephant reached the Philippines, we can look at this picture, this is Southeast Asia and Oceania during the last ice age tens of thousands of years ago, you can see the sea level decline to connect a series of islands in the western Part of the Malay Archipelago, and the saber-toothed elephant reached the Philippines along these islands. At the top of the picture, you can also see that the land extends south of Hainan Island.
Today, there are still wild Asian elephant populations on the islands of Sri Lanka (Ceylon), Sumatra and Kalimantan (Borneo).
Therefore, if the elephants on Hainan Island did not have human interference, they could multiply on the island. However, according to the evolution of mammalian "island dwarfing" (the tendency of large mammals to become smaller due to the limitations of the island environment), the elephants on Hainan Island are estimated to be only as large as pigs, and they are not called "elephants". Refer to dwarf elephants on Mediterranean islands.
Sumatran elephant
Curiously, Asian elephants on the island of Sri Lanka are larger today, while Asian elephants in Sumatra and Borneo are smaller, but Sumatra and Borneo are much larger than on The island of Sri Lanka. This requires professionals to study to come up with an answer.
Therefore, Hainan Island was once full of beasts, but these rare animals disappeared in the long river of history and did not continue.