Two species of gibbons have become extinct in the wild in my country. Can they come back?

On September 6, at the annual working meeting of the National Endangered Species Scientific Committee, the "China Primate Endangered Status Assessment Report 2022" was released. The report shows that in the past few decades, the white-handed gibbon and northern white-cheeked gibbon distributed in China have not been monitored in the wild , meeting the criteria for extinction in the wild.

White-handed gibbons in a national park in Thailand | JJ Harrison / Wikimedia Commons

These two gibbons are still distributed in Southeast Asia, but this result is still worth our attention. Behind the regional extinction is the reason why gibbons have gone from being "crying on both sides of the river" to being trapped in Yunnan and Hainan. Can these two gibbons come back? Can other gibbons in my country survive the crisis?

The missing gibbon

In recent decades, the white-handed gibbon (Hylobates lar) in China is only distributed in Cangyuan, Ximeng, Menglian and other places in Yunnan. The last sighting of it was in 1988, and the last time people heard it calling was in 2000. In the many searches for the white-handed gibbon since then, people have not seen any traces of it, nor have they found any signs of eating or defecating, and have not even heard it calling.

Gibbons are arboreal and cautious by nature, so visual search is not easy. However, all gibbons have the habit of calling in the early morning, and their calls can travel very far, so calling is an important piece of evidence for searching for gibbons. | FunkMonk / Wikimedia Commons

Although there are wild populations of white-handed gibbons in neighboring Thailand, Laos, Myanmar and Malaysia, scholars have found based on a study of four specimens in Menglian, Yunnan that the white-handed gibbons in China are morphologically different from those distributed in neighboring countries and may be an independent subspecies - the Yunnan subspecies of white-handed gibbons (H. lar yunnanensis). This subspecies has no other habitats in the world, and there is no clear record of this subspecies being raised in zoos in China; therefore, the extinction of white-handed gibbons in the wild in China may also mean that this subspecies will disappear completely - however, this conclusion requires more research to be finalized.

A pair of white-handed gibbons, but they are not the Yunnan subspecies of white-handed gibbons distributed in my country. It is difficult for us to find clear photos of the Yunnan subspecies. The two white-handed gibbons in the photo have significantly different fur colors, which is not caused by gender or age differences. The fur colors of white-handed gibbons are very rich, ranging from pure black to beige. | Matthias Kabel / Wikimedia Commons

The last habitat of the northern white-cheeked gibbon (Nomascus leucogenys) in China is also concentrated in Yunnan, specifically Mengla, Jiangcheng, and Luchun. Since the mid-to-late 1980s, China has conducted multiple rounds of research and investigations on the northern white-cheeked gibbon, but the evidence of their existence has become less and less . In the 2011 survey, people could neither find any traces of gibbons nor hear their voices. In 2018, photographer Xu Sheng photographed a male northern white-cheeked gibbon in a rubber forest near the China-Laos border, but subsequent investigations were still disappointing - not only did the researchers return empty-handed, but local residents also said they had not seen or heard gibbons for many years. The one photographed may have wandered from Laos, or it may have been a captive gibbon that was abandoned or escaped, and it soon disappeared without a trace.

Slide to see the male and female northern white-cheeked gibbons. The male and female northern white-cheeked gibbons have significant differences in appearance. The male has black hair and the female has brown hair.｜Grendelkhan & Bilby / Wikimedia Commons

At present, there are still wild populations of northern white-cheeked gibbons in northern Laos and northern Vietnam, and there are also considerable captive populations in my country. However, if we look back at history, we will find that too much of the gibbon's habitat in my country has disappeared.

The monkeys on both sides of the river kept crying

There are 20 members in the gibbon family. In addition to the white-handed gibbon and the northern white-cheeked gibbon, there are also western black-crested gibbons, eastern black-crested gibbons, Hainan gibbons and Tianxing gibbons distributed in China. At present, they are only distributed in Yunnan, Guangxi and Hainan.

There are four other species of gibbons distributed in my country, from top to bottom:

Western black-crested gibbon (Nomascus concolor)｜Fan Pengfei

Eastern black-crested gibbon (N. nasutus)｜Zhao Chao

Hainan gibbon (N.hainanus)｜Chen Qing

Hoolock tianxing｜Zhao Chao

However, historically, gibbons do not live only in tropical areas. Li Bai wrote "The monkeys on both sides of the river are crying incessantly, and the light boat has passed through thousands of mountains", proving that the Three Gorges area was the habitat of gibbons at that time. Scientists have also found gibbon mandibular fossils in this area. Through the search of local chronicles, it can be found that there were four areas in China with relatively dense records of gibbons in history , namely: the junction of Hubei, Shaanxi and Henan in the central part, the junction of Zhejiang, Fujian and Jiangxi in the southeast, Yunnan and Guangxi in the southwest, and Guangdong and Hainan in the south.

The ancients were no strangers to gibbons. In the pre-Qin period, there were records of the royal family of Chu keeping gibbons in captivity; the Liye Qin bamboo slips unearthed in recent years describe that in the 27th year of Qin, Qianling County dispatched hundreds of people to capture gibbons alive and presented them as pets to the royal family. The gibbon bones unearthed from Pit 12 in Chang'an District, Xi'an, provide further evidence for this record - the owner of this tomb was the grandmother of Qin Shihuang Yingzheng, Queen Mother Xia, and this gibbon was her pet. Subsequent research further found that this gibbon is different from the gibbons that exist today. It is an extinct species named Junzi imperialis.

Gibbon skeleton found in the tomb of Queen Dowager Xia of Qin Dynasty. This gibbon is different from all the gibbons alive today｜Samuel Turvey/ZSL

In the more than 2,000 years since the pre-Qin period, China's climate has not remained unchanged, but the distribution of gibbons does not seem to have been greatly affected - records of gibbons in local chronicles still appear frequently, and the northernmost one is even in Qingyang, Gansu, and the average altitude of the distribution area has increased from 486 meters to 1,069 meters. In the late Ming and early Qing dynasties, China also experienced a small ice age, but during this period, gibbons not only did not retreat southward, but instead moved slightly northward.

Since gibbons don't seem to be afraid of the cold, why did they later move south and are now confined to tropical areas?

Apes and humans fight for land

The brief northward expansion in the late Ming and early Qing dynasties was actually a turning point - after that, the gibbon habitat in China showed a rapid trend of retreating southward and fragmentation , which was closely related to the population changes at that time.

The distribution of gibbons in my country over the past 500 years, from left to right and from top to bottom, in 1550, 1650, 1775, 1875, 1925 and 2000 | References [4]

Due to years of war, the population loss rate in the late Ming and early Qing dynasties was very alarming. According to different estimates, the population loss in the Central Plains at that time was close to 80%, reaching a low of 9.2 million in the 18th year of Shunzhi (1661). After that, the country gradually became peaceful, and with the introduction and promotion of some high-yield crops from South America, the population began to grow rapidly, exceeding 200 million by 1775, and maintained a roughly growing trend for the next few hundred years.

With more people, more farmland is needed, but this also means that more forests will be cut down and converted into farmland . A large number of forests in the mountainous areas of Fujian were reclaimed and converted into tea plantations in the late Qing Dynasty, which devastated the largest gibbon habitat in China. The same story happened in several other gibbon distribution areas - the gibbon population in the Three Gorges area declined first, and had drastically decreased in the Song Dynasty in the 12th century; the gibbons in Shaanxi survived until the early Republic of China; the mountains in the Guangdong and Hainan regions were developed in the early Ming Dynasty, and the gibbons in northern Guangdong fell into decline, with only some areas of Hainan Island retaining a limited population.

In fact, the story of people and wild animals fighting for land did not only happen in ancient times. The northern white-cheeked gibbon, which was declared extinct in the wild in my country, last lived in Xishuangbanna Prefecture. With population growth and the large-scale planting of cash crops, the proportion of native forests in Xishuangbanna Prefecture today has dropped by 20% compared with the 1970s, and the area of ​​rubber forests has increased from 1.3% of the total area of ​​the prefecture to 12%; even in the native forests that have not been cut down, there are a lot of understory planting and picking, and even in the core area of ​​the reserve, there are similar situations - all of which have aggravated the fragmentation of the northern white-cheeked gibbon's habitat. The same is true for white-handed gibbons. The number of the last group of white-handed gibbons has dropped sharply, which is directly related to the large-scale logging of the original forests around the Nangun River Reserve in the 1960s and 1970s.

The rubber forests in Xishuangbanna look lush and green, but compared with the native forests, the ecological value of the rubber forests is actually very low | Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences

In addition to habitat changes caused by human activities, hunting may also be an important factor leading to the decline of gibbon populations . In addition to obtaining fur, gibbons have many "uses", such as their bones can be made into flutes or traditional ethnic medicine "Lunanni"; there are rumors that chopsticks made from gibbon upper limb bones can detect poison, which has led to commercial hunting of gibbons in Guangdong and Hainan after the founding of the People's Republic of China. In 2017, during a visit to northern white-cheeked gibbons, more than half of the male respondents over the age of 50 had participated in or witnessed the hunting of northern white-cheeked gibbons. At the end of 2018, investigators clearly heard at least three gunshots while searching for gibbons at the border junction of China, Laos and Vietnam.

Will they come back?

There are still wild populations of white-handed gibbons and northern white-cheeked gibbons in other countries. If the habitat can be restored, the extinct gibbons may spread back to China .

However, cross-border coordinated protection is actually more difficult; moreover, the protection strength of several neighboring countries where these two gibbons are distributed is worrying . In a 2018 survey on northern white-cheeked gibbons, many residents living on the border mentioned that a few years ago, Laotians came to the village to sell live northern white-cheeked gibbon cubs, and some people in the village bought and raised them (this also made researchers suspect that the gibbon photographed in 2018 may be a domestic pet that escaped or was abandoned). Gibbon meat has even appeared in the wild game market in border areas. In addition, the habitat pressure in our country may be even more intense in these countries.

A gibbon in a painting by Yi Yuanji during the Song Dynasty. The gibbon was tied up with a jeweled rope and was obviously a pet of a wealthy family; however, in modern times, the phenomenon of keeping gibbons as pets may still exist.

Another way to return these two gibbons to the wild is to carry out artificial breeding and release them into the wild . The northern white-cheeked gibbon is the most numerous captive gibbon in China, with more than 100 individuals currently in captivity. However, there are still many problems to be solved in order to achieve release into the wild - there is inbreeding among gibbons in domestic zoos; the classification of gibbons is complex, and some breeding institutions have not yet been able to accurately classify the gibbons they keep in captivity, especially the northern white-cheeked gibbon and the yellow-cheeked gibbon, which are easily confused, so there may be hybridization problems among captive gibbons; in addition, the gibbons in some breeding units may come from illegal sources, lack specific information about gibbons, and the pedigree management is even more chaotic.

However, the most important question is, even if we can maintain the lineage of captive gibbons and overcome their genetic diversity problems, where should we release them? Is our habitat ready?

The number of Hainan gibbons is now less than 50, but it is the only gibbons with a stable population; conservationists have expanded their habitat and built a rope bridge for them to pass through｜Chan, BPL, Lo, YFP, et al. (2020)

From paleontological evidence, China is likely to be the original evolutionary site of existing gibbons. It is also the country with the richest gibbon species (only one species less than Indonesia) and the country with the largest possible distribution area in history. But at present, the situation of gibbon protection in China is not optimistic. Moreover, the environmental pressures that overwhelmed the white-handed gibbon and the northern white-cheeked gibbon also occurred in other gibbons . If changes are not made soon, the other four gibbon species may repeat today's story.

Before the end of 2022, we have witnessed several extinction stories around us. Recording such stories is not pleasant, but such records are still meaningful. Scientific research and conservation work are the basis for ecological restoration, but at the same time, if more people understand and pay attention to these endangered species, perhaps more people will support and participate in protection work - until those creatures that originally shared a home with us return to this land.

References

[1] Fan Pengfei. Taxonomy and conservation status of gibbons in China[J]. Acta Theriologica Sinica, 2012, 32(3):11.

[2] Song Zhiyong, Yang Hongpei, Yang Zhengbin, et al. Current status of northern white-cheeked gibbon population in Xishuangbanna and its conservation strategies[J]. Journal of Western Forestry, 2017, 46(3):6.

[3] Unfortunately, we did not find any northern white-cheeked gibbons this time. Yunshan Conservation. https://mp.weixin.qq.com/s/bw4hWROV9ekVyKZtrcZlMw

[4] Zhou Yunhui, Zhang Peng. Distribution changes of gibbons in China over the past 500 years[J]. Acta Theriologica Sinica, 2013, 33(3):9.

[5] Li Yunqiao, Zhu Youshuai, Yang Yuzhao, et al. Current status and conservation strategies of captive gibbon populations in China[J]. Forestry Survey and Planning, 2018, 43(2):5.

[6] Ma Shilai. On the Chinese origin of gibbons[J]. Acta Theriologica Sinica, 1997, 17(1):2.

Author: A man is wandering

Editor: Mai Mai

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