It’s 2022, do you want to see something tiger-like?

The Year of the Tiger is here, Fat Tiger wishes you a happy new year.

As one of the twelve zodiac signs, the tiger has always been of high status in traditional Chinese culture. Most of the words related to the tiger have beautiful meanings, such as "crouching tiger, hidden dragon", "tiger crouching and dragon coiling", "tiger is mighty", etc.

In East Asia, the tiger is known as the "king of beasts", but it did not rule East Asia from the beginning. When it first appeared, it was suppressed by the saber-toothed tiger subfamily. Lions from Africa also entered East Asia and competed with tigers for the throne of the king of beasts for a long time.

In this battle for supremacy among East Asian beasts, why did the tiger stand out and win the final victory? Today we will take a look at the tiger's inspirational story.

Image source: veer gallery

Part 1

The fate of the ancient Chinese tiger: oppression from above and constant competition from below

The ancestor of today's tigers is the ancient Chinese tiger (Panthera palaeosinensis), which was first discovered in North China more than 2 million years ago. It can be found in today's Henan and Gansu regions.

Although there is no evidence that North China is the origin of the tiger, North China at that time must have been within the range of the tiger's origin.

Ancient Chinese tiger skull fossil, found in Yangshao Village, Mianchi, Henan (Photo: Gao Wei)

Today, tigers are the absolute overlords in East Asia, but 2 million years ago, the ancient Chinese tiger, which was only the size of a jaguar, was just an ordinary member of the ecosystem.

At that time, the dominant species in the ecosystem were saber-toothed cats, including giant chin tigers, saw-toothed tigers, saber-toothed cats, and giant cheetahs of the subfamily Felinae. Large saber-toothed cats always threatened the life safety of the ancient Chinese tiger, while the giant cheetah, which was similar in size to the ancient Chinese tiger, formed a fierce competition with the ancient Chinese tiger.

In addition to saber-toothed tigers, there were many other ferocious carnivores in East Asia at the time, such as giant hyenas, leopard hyenas, spotted hyenas, etc. They moved in groups and were aggressive everywhere, posing a certain threat to the ancient Chinese tiger. There were also canines as big as wolves, such as Andersen's jackals, which also moved in groups of three or five and constantly fought with them.

The skull of the representative saber-toothed tiger of the Early Pleistocene in East Asia - Giant Jaw Tiger (Photo: Jiang Zuoqigao)

Around 1 million years ago, the ancient Chinese tiger gradually evolved into a real tiger. As they had adapted to the forest environment early on, early tigers thrived in the forest-dominated eastern Asia. They spread along the jungle belt and soon spread throughout East Asia and Southeast Asia, and even crossed the land bridge to today's Sumatra and Java.

By the Middle Pleistocene (780,000-130,000 years ago), the tiger had reached the size of today's Siberian and Bengal tigers. In addition, during this period, the saber-toothed tigers and giant cheetahs that dominated the Early Pleistocene gradually disappeared or became extinct, so tigers began to dominate East Asia.

Part 2

The ancient Chinese tiger finally ascended the throne? It's too early to celebrate

However, just when the development of the ancient tiger seemed promising, a new threat quietly arrived from the west. 800,000 years ago, lions also set out from Africa and entered the Eurasian continent, then moved eastward, quickly occupying Europe and western and northern Asia, and successfully entered the American continent across the Bering Land Bridge, becoming the world's dominant power ruling the five continents.

The representative of lions in Eurasia at that time was the cave lion (Panthera spelaea), which could weigh 300 to 400 kilograms, much larger than tigers of any period, and was one of the largest cats in history. Because lions and tigers are closely related and have similar diets, there is fierce competition between the two.

The powerful lions occupied the northern part of Eurasia, hindering the expansion of tigers, which prevented them from leaving Asia. Many other species living in East Asia, such as jackals, Asian bears, and brown bears, successfully migrated to Europe during this period and thrived because they had no direct competitors.

In this way, the tigers of this period could only "lie on straw and eat bitter food" in East Asia, waiting for the next opportunity for expansion.

The evolution of modern tigers: survivors of climate change

Due to the dramatic climate fluctuations during the Quaternary Ice Age in the Middle Pleistocene, the distribution range and population size of tigers also fluctuated, and population replacement or local extinction occurred from time to time. The research team of Professor Luo Shujin of Peking University found that about 110,000 years ago, tigers in South China were likely the ancestors of modern tigers. They gradually expanded their distribution range during climate fluctuations, reaching the ancient Sundaland in the south and entering the Indian region in the west.

It was not until about 15,000 years ago that the last ice age ended and the Earth entered the Holocene. The climate became warmer and wetter, and grasslands were largely replaced by forests. Cave lions, which had long lived in the north and adapted to the grassland living environment, gradually declined and became extinct in the collapse of the ecosystem at the end of the Pleistocene due to lack of prey. Tigers not only survived, but also took advantage of the dividends of forest development to expand their territory. The Siberian tigers even moved westward along the North China-Hexi Corridor, entering Xinjiang, Central Asia, northern Iran and the Caucasus, forming the Caspian tiger population.

At the same time, as sea levels rose, the Sunda region became an archipelago, and the surviving tigers on these islands were isolated on small islands with dense rainforests and were forced to shrink to a very small size, becoming today's Sumatran tiger, Javan tiger and Bali tiger populations.

Migration of modern tigers, red represents modern distribution, orange represents historical distribution

(Image source: Luo et al., 2019)

About 7,000 to 8,000 years ago, the tiger's sphere of influence exceeded any period in history. It was developing at its peak and finally earned the title of "King of the Forest".

Conclusion

Looking at the evolutionary history of tigers, we can see that tigers have been adapted to jungle life from the beginning, but this ecological strategy has also limited their development. Against the backdrop of global cooling and grassland expansion, jaguars, saw-toothed tigers and lions quickly dominated the five continents, but tigers "peaked at their debut" and have since stagnated for a long time, always shrinking in eastern Asia and unable to move out.

However, every loss has its own gain, which is one of the important reasons why tigers have survived successfully to this day and are still the dominant species in East Asia. Although the powerful and ferocious carnivores living in the northern grasslands prospered for a while, they could hardly rule for a long time under the drastic climate and environmental fluctuations during the glacial and interglacial periods of the Quaternary period. They appeared and disappeared in batches like crucian carp crossing the river. The climate in the jungles of South China where tigers live is stable. When the environment of the northern grasslands deteriorated, tigers could still live and work in South China. Therefore, tigers are still the king of beasts on the land of China.

Survival of the fittest and natural selection have always been the unchangeable laws of nature. How to make oneself stronger and more adaptable to the ever-changing living environment so as to survive tenaciously is the law of survival that we can understand from the evolutionary history of tigers.

References:

[1] Hemmer, H., 1967. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte 129, 83–96.

[2] Luo, SJ, Liu, YC, Xu, X., 2019. Tigers of the World: Genomics and Conservation. Annu Rev Anim Biosci 7, 521-548.

[3] Zdansky, O., 1924. Jungtertiare Carnivoren Chinas. Geological Survery of China, Peiking.

[4] Qiu Zhanxiang, Deng Tao, Wang Banyue, 2004. Early Pleistocene mammal fauna of Longdan in Dongxiang, Gansu. Science Press, Beijing.

Produced by: Science Popularization China

Produced by: Jiang Zuoqigao

Producer: Computer Network Information Center, Chinese Academy of Sciences

(The images with source indicated in this article have been authorized)

The article only represents the author's views and does not represent the position of China Science Expo

This article was first published in China Science Expo (kepubolan)

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