Dongdao is one of the islands in the Xisha Islands in the South my country Sea. It is an out-and-out coral island. The East Island is very small, the entire island is only 1.7 square kilometers, but more than 400 bison were surprisingly found on this small island. What's even more surprising is that these bison look very similar to domestic oxen. Where did these bison come from?

More than 400 bison suddenly appeared on East Island, which may have existed for more than 300 years!

The many islands in the Xisha Islands are centered on Yongxing Island, which is about 330 kilometers away from the land port. In the long course of history, the island has experienced countless times from being submerged to seeing the light of day again in the ups and downs of the sea.

East Island occupies 1.7 square kilometers but is still the second largest island in the Paracel Islands. It has more tropical vegetation and the year-round green forest is particularly suitable for animals to live in.

According to common sense, resources on coral islands are generally scarce and it is difficult for species to be rich. Dongdao is an exception. There are more than 36 species of birds living here. The scientific researchers also discovered a huge surprise after arriving!

In 2003, Chinese scientific expedition personnel landed on Dongdao, hoping to gain a deeper understanding of its true appearance. When the scientific expedition personnel went to the island, they were surprised to find a large number of cattle on the island. When the cattle saw the stranger approaching, they became extremely vigilant and immediately ran into the jungle.

Careful scientific researchers discovered that the bison living on the island looked very similar to oxen and were also shorter in stature. Yellow cattle are a species native to northern my country. Obviously, these wild cattle are not native to the south. So how did these bison end up on this island?

Scientific expedition personnel visited other islands, and there was no trace of bison on other islands. Why are traces of cattle found in the southernmost part of our country? After the scientific expedition personnel discovered this herd of bison, they immediately launched an investigation.

To explore the origins of bison, you must get close to the herd. But these bison have lived on the island for such a long time and may have never seen humans. It is really impossible to get close. So experts plan to start from the wild living environment and want to learn something about it.

For cattle to survive on the island, in addition to abundant food, they also need fresh water to survive, and there is a crescent-shaped pond on the south side of the island. There are more rainy days on the small island, and the rainy water will accumulate in the pond, providing a source of survival water for the creatures on the island.

When the experts arrived at the pond, they found a pile of cow dung around the pond, which was indeed smelly. This is enough to show that cattle often come to this pond to drink water and bathe.

Experts took bison excrement from the pond and went back for analysis. The test found that it was fine. After testing, they found that the excrement was at least 300 years old! This means that the bison herds here have survived for at least 300 years.

The mysterious origin of the bison herd

According to calculations, this island has sunk at least three times in thousands of years. The breed that looks exactly like an ox also comes from northern my country, so it definitely cannot be a local breed. How did 400 bison end up on the island?

There are many story versions about the mysterious origin of bison. Some people say that this is a breed brought to the island by the generals during the Han Dynasty's southern expedition. Since the island's harsh environment was not suitable for people to be stationed and guarded, a group of cattle were put on the island to declare sovereignty.

The bison placed on other islands gradually died out due to lack of water resources and food. Due to the large amount of vegetation and fresh water resources on the East Island, the cattle on the island have gradually turned into bison, and the bison have lived and multiplied here to this day.

Some people say that fishermen brought the cattle to the island, while others say that Zheng He brought the cattle to the island during his voyages to the West. There are different opinions on the origin of the bison.

If calculated based on time, it should be the late Ming and early Qing dynasties 300 years ago. The last years of the Ming Dynasty were a period of dynasty change. People in the Ming Dynasty went south to escape the war. If they brought this batch of bison to the island, it seems to be reasonable in terms of time and inference.

No matter how the bison got to the island, it is indeed a magical thing that they can reproduce on the small island to this day.

The bison herd has survived for at least 300 years, or has it been possible to cross over?

Since the bison herd has lived on the East Island for 300 years, and there are no exotic bison breeding, if they want to reproduce on the island, there will definitely be backcrossing.

What is backcrossing? In layman's terms, it is the inbreeding of animals. Imagine that there are only so many cows on the island. During the breeding season, they basically cannot find other cows for crossbreeding. They can only find them among their own little partners. Perhaps bison mate with their sisters to produce the next generation.

Whether it is incest marriage in humans or backcrossing between animals, it is a great risk to future generations. Offspring born between close relatives have a particularly high probability of having recessive genes highlighted.

The bison found in the East Island are all very short in stature, and even the bulls are no more than 1 meter tall. Scientists say the reason for this short stature may be the "undesirable" consequences of backcrossing in the small number of bison.

Although there may not be any ethics between animals, scientists have found that many animals avoid backcrossing in order to ensure good genes. Animals such as lions and tigers do not backcross. Unless absolutely necessary to avoid genocide.

Backcrossing will highlight the bad genes present in animals. Fold-eared cats, hairless cats, etc. are all the offspring of bad genes. This kind of inbreeding will also make the genes of a certain species more and more similar, and eventually lead to extinction. Why are there backcrossing phenomena among cattle that have survived on the East Island for more than 300 years, but they have not become extinct yet?

In fact, scientists have also conducted backcrossing experiments in order to detect bad genes in animals and plants, so as to breed excellent varieties. Some endangered animals also undergo backcrossing in order to keep the species alive.

So although backcrossing has disadvantages, it also has certain advantages. The bison on the East Island can survive for such a long time, which is enough to prove that the bad recessive genes among them are likely to be eliminated, and the remaining genes can continue to reproduce.

However, since there is no ban on hunting bison in the Nansha Islands, due to human hunting, the number of bison on the island during 2011 The number of bison plummeted to below 50. At this time, everyone realized that the bison on the island should be protected. Later, some excellent breeds were transported to the island to coexist with the local bison to avoid the extinction of the bison.

In fact, the environment on the island is very stable. If there is no man-made damage, animals and plants will actively adapt to environmental changes and survive on the island for a long time.

The bison on the island have declined sharply and are almost extinct, which is also the result of human intervention. Because of human intervention, too many species of animals and plants in the world have become extinct and will never be seen again. I hope that on this small island, they will no longer be disturbed and they will have a paradise.