Can you imagine? These "standard" animals in zoos have long been endangered species...

According to the 2019 and 2020 assessments of the International Union for Conservation of Nature Red List of Threatened Species, Asian elephants and African savanna elephants are now endangered species, while African forest elephants are now critically endangered.

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For most people, this fact may be very surprising. The elephants kept in almost every zoo have long been on the path of endangered and critically endangered.

Today is World Elephant Day, so let’s get to know these long-nosed friends better.

After 60 million years of evolution, only 3 species remain

With its magnificent size and peculiar appearance, elephants have become one of the most eye-catching animals on earth. In fact, from its unique classification status and long-standing origin, elephants are indeed a miracle in the history of biological evolution. Elephants are classified as Proboscidea, of which only three species remain: Asian elephants , African savanna elephants and African forest elephants , and are very distantly related to other animal groups.

From left to right: Asian elephant, African savanna elephant, African forest elephant. Asian elephants have two obvious ridges on their heads, while African savanna elephants and African forest elephants have one ridge. However, the ear tips of African savanna elephants are more pointed, while the ear tips of African forest elephants are more rounded, and their tusks are more vertical to the ground.

The earliest known Proboscidea species is the ancient elephant beast that lived 60 million years ago . In the long history of the earth, Proboscidea has evolved into many members, but in such a long time, their evolutionary direction is generally the same, most of them have a huge body, long trunks and tusks. Outside of Proboscidea, few animals have evolved similar forms. If Proboscidea is likened to a large family, then it can be understood that the members of this family have adhered to their own traditions since ancient times, and have almost never been imitated by people outside the family.

Unfortunately, today, most Proboscidea species have become extinct. Africa is the origin of Proboscidea, and the Asian elephant is the only surviving Proboscidea species outside of Africa.

Elephants, forest farmers and ecological engineers

Their unique evolutionary history makes them play an irreplaceable and important role in the ecosystem. Elephants are called "forest farmers" and "ecological engineers". The activities of Asian elephants have a profound impact on the plant communities in the forest, and thus affect almost all forest species.

In tropical forests, for plants with large fruits and few seeds, such as durian and jackfruit, Asian elephants’ eating is almost the only effective way for them to spread seeds. Birds and monkeys cannot carry these large fruits, and animals such as wild boars and bison will chew the seeds into pieces, making them unable to germinate. Elephants like to eat the fruits of plants, and they are not very careful when chewing, and their digestion ability is not strong, so the seeds can be excreted intact with feces. Elephants also have a wide range of activities, generally traveling more than 5 kilometers a day. When the eaten seeds are excreted after 24-48 hours, they have been carried to a very far place. In Asia, there are more than 300 species of plants that rely on Asian elephants to spread their seeds.

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Further research shows that elephants' ecological impact is not limited to the forests they inhabit, and they can even fight global climate change . When elephants move on the forest floor, they clear out some smaller saplings, an operation similar to "forest tending" in forestry management, which makes the trees more sparse, but each tree will grow larger, and the total biomass will increase in the end.

Specifically, research in the African rainforest found that the presence of African forest elephants increases the biomass of each hectare of forest by 26-60 tons and increases the carbon sink of trees by 7%. In other words, each African forest elephant can reduce carbon dioxide in the atmosphere by 9,500 tons . In the forests of Asia, Asian elephants may also play an important role. Global warming caused by greenhouse gases such as carbon dioxide is one of the major environmental crises facing mankind. Now it seems that protecting elephants is also an effective means to deal with this crisis.

"Umbrella species" is a concept in conservation biology, referring to species whose living environment requirements can cover the living environment requirements of many other species. The Asian elephant is a typical umbrella species. The range of an Asian elephant can reach hundreds of square kilometers. To support a population of Asian elephants, there must be a large enough protected area, and such a protected area can also provide enough living space for many other species.

A herd of Asian elephants in Sri Lanka's Khao Lak National Park. Image copyrighted by the database, no permission to reprint

At the same time, the Asian elephant is a "flagship species" in conservation biology, and it has a strong public appeal. From 2020 to 2021, the northward migration of Asian elephants from Xishuangbanna all the way to Kunming and returned safely, which attracted worldwide attention and was a landmark event in China's wildlife conservation. At the same time, elephants have many important roles in scientific research. For example, elephants have 20 copies of the p53 gene, which makes the incidence of cancer in elephants very low. By studying the principle of elephants inhibiting tumor occurrence, it provides new ideas for humans to fight cancer .

How are our wild Asian elephants doing?

According to the latest data released by the Yunnan Provincial Forestry and Grassland Bureau, there are about 360 wild Asian elephants in Yunnan, China. Compared with the total number of 50,000 in Asia, the number in China does not seem to be large, but it is very important. Because there are no other wild populations of Asian elephants east or north of Yunnan, this is already the edge of the distribution of Asian elephants .

Historically, Asian elephants were once distributed in the Yellow River Basin of China. Under the influence of environmental changes and human activities, they gradually retreated to Xishuangbanna, Pu'er and Lincang in Yunnan. Protecting the last habitat of Asian elephants in China also protects the hope of rejuvenation for the Asian elephant populations around the world. Moreover, in the context of the overall decline in the number of wild Asian elephants in the world and the entire species being rated as endangered, the growth of the Asian elephant population in China is very valuable .

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At present, the largest population of Asian elephants in my country is distributed in the area from the Mengyangzi Nature Reserve in Xishuangbanna National Nature Reserve to the southern part of Pu'er City, with a number of about 200. There are also dozens of wild Asian elephants in the Menglazi Nature Reserve and the Shangyongzi Nature Reserve in Xishuangbanna. The elephant populations in these two reserves have cross-border exchanges with the elephant populations in neighboring Laos, with a total number of more than 100. With the increase in population and the restoration of habitat, there is hope that exchanges can be achieved with the Mengyang population in the future to form a large aggregate population.

In addition, there are more than a dozen Asian elephants in the Menghai-Lancang area and the Nangun River National Nature Reserve in Lincang. Realizing genetic exchange between small and large populations through measures such as building corridors and artificially transferring individuals is also an important issue in the protection of Asian elephants in China .

Author: Zhou Fangyi

Reviewer: Huang Chengming, Researcher, Institute of Zoology, Chinese Academy of Sciences

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