As many as half the global population of donkeys could be wiped out in just five years, due to a surge in demand for their hides, which are used in traditional Chinese medicine.

Populations are reportedly collapsing in countries across Africa, South America and Asia, with animals including sick mares and foals being stolen, illegally transported and killed, according to a report from the international charity The Donkey Sanctuary.

The organisation has warned the species is now “in a state of global crisis”, as traders target their skins to export as an ingredient for eijao – donkey hide glue, a popular health product in China – though one without any medical evidence behind its utility.

Increasing demand for ejiao has led to an unsustainable number of donkeys being slaughtered, and the emergence of criminal gangs kidnapping the animals for their hides, which are sold in their millions every year.

The Donkey Sanctuary report reveals the supply of donkey skins is currently unable to meet demand in China, which uses around 4.8 million hides per-year for ejiao production. As a result, traders in Africa, Asia and South America are exporting additional skins to China.

World's most endangered animals Show all 17 1 /17 World's most endangered animals World's most endangered animals Amur Leopard Endemic to the far east of Russia, the Amur Leopard has a population of around 84 and is critically endangered. Here follows every species that the WWF lists as critically endangered. Getty World's most endangered animals Sumatran Elephant The Sumatran elephant population now stands at only 2400-2800 Getty World's most endangered animals Yangtze Finless Porpoise Endemic to China's Yangtze River, the Yangtze finless porpoise has an estimated population of 1000-1800 Kenichi Nobusue World's most endangered animals South China Tiger When discovered in the 1950s, the South China tiger population was estimated to be 4000, by 1996 it was estimated to be only 30-80. Scientists consider the tiger to be "functionally extinct" as one has not been sighted for over 25 years World's most endangered animals Sumatran Orangutan The Sumatran orangutan was once found across the island of Sumatra and even further south on Java. Today it is found only in the island's north and its population stands at 14,613 Getty World's most endangered animals Western Lowland Gorilla Though it is the most populous of all gorilla subspecies, the western lowland gorilla is still critically endangered and its population has declined by 60% in the last quarter century Getty World's most endangered animals Sumatran Rhinoceros The Sumatran rhinoceros is the smallest of the surviving rhinoceros species. Only 80 are known to be living today. The last male Sumatran rhino in Malaysia died on 28 May 2019 Willem V Strien World's most endangered animals Sumatran Tiger There are fewer than 400 Sumatran tigers left today. They are severely threatened by deforestation and poaching Getty World's most endangered animals Eastern Lowland Gorilla Half of the rainforest of the Democratic Republic of Congo in which these gorillas live has been destroyed the past 50 years. There were 17,000 Eastern Lowland gorillas in the 1990s but scientists estimate their population has declined by over 50% since then Getty World's most endangered animals Vaquita The world's rarest marine animal has a population of only 30. They were discovered in 1958 and are endemic to Mexico's Gulf of California Paula Olson / NOAA World's most endangered animals Javan Rhino The most threatened of all rhino species, there are only an estimated 58-68 Javan rhinos left Reuters World's most endangered animals Saola The saola was first sighted in 1992, being the first large mammal to be discovered in over 50 years. Scientists have only sighted saola in the wild four times and it is considered critically endangered World's most endangered animals Malayan Tiger The Malayan Tiger population now stands at only 250-300 Getty World's most endangered animals Hawksbill Turtle The population of the Hawksbill Turtle has declined by more than 80% in the last century. They are threatened by black market poachers who kill them for their shell Getty World's most endangered animals Black Rhino The population of the black rhino dropped by 98% in the years 1960-1995 due to poaching, it stands today at around 5000 Getty World's most endangered animals Cross River Gorilla The population of the Cross River gorilla has been damaged by deforestation and poaching, it now stands at 200-300 Julie Langford World's most endangered animals Bornean Orangutan The population of the Bornean orangutan has been reduced by over 50% in the past 60 years, now standing at around 104,700. Their habitat has been reduced by at least 50% in the 21st century Getty

Donkey populations in China have collapsed by 76 per cent since 1992. And since 2007 populations have declined by 28 per cent in Brazil, by 37 per cent in Botswana and by 53 per cent in Kyrgyzstan.

With just under five million skins needed every year for ejiao production, the industry would require more than half the world’s current donkeys over the next five years to meet demand.

The demand for donkeys is also driving an animal welfare crisis, with the potential to spill over into becoming a human disease issue as poor hygiene in slaughterhouses has seen a rise in dangerous pathogens including anthrax alongside equine diseases such as strangles and equine flu.

Donkey skins laid out to dry for use in eijao (The Donkey Sanctuary)

The report says many skin trade donkey handlers have little or no training in animal handling, often resorting to cruel and illegal methods of controlling donkeys such as kicking, dragging and the use of spiked sticks called goads.

Conditions in many of the donkey slaughterhouses are appalling. One slaughterhouse in Kenya was immediately closed after witnesses recorded footage of dead and dying donkeys some with open, maggot-infested wounds. Foetuses were also seen as well as skinned carcasses dumped next to live donkeys awaiting slaughter.

The slaughterhouse has since reopened.

In Bahia, in north-eastern Brazil, 800 donkeys were found starving to death in holding pens alongside hundreds of rotting carcasses which had polluted their only water source.

The charity has also discovered links between the donkey skin trade and other serious wildlife crime, with some traders offering donkey skins for sale on online platforms that are also selling illegal wildlife products including ivory, pangolin scales and rhinoceros horn. In one instance, tiger skins were found hidden underneath donkey skins.

Mike Baker, chief executive of The Donkey Sanctuary, said: “This is suffering on an enormous and unacceptable scale. This suffering is not just confined to donkeys as it also threatens the livelihood of millions of people.