Official records show that pangolins are being illegally traded on a 'shocking' scale, according to a report.
The globally threatened animals are sought for their scales which are used in traditional Chinese medicine.
Annual seizures have been estimated at roughly 10,000 animals but experts warn the illegal trade is far greater
Chinese enforcement officials worked with researchers from the UK to assess the extent of the problem.
Zhao-Min Zhou, from the Public Security Bureau for Forests in China's Yunnan province, worked with researchers from the University of Oxford to analyse official records of pangolins seized from smugglers.
The findings are published in the journal Frontiers in Ecology and the Environment.
'The numbers of pangolins traded are shocking, and all the more so considering the pharmaceutical pointlessness of the trade. This trade is intolerably wasteful,' said Prof Macdonald, director of the University of Oxford's Wildlife Conservation Research Unit (WildCRU), and a co-author of the paper.
He praised the leadership of Mr Zhou in the study, which gives conservationists the first glimpse of official records of seizures.
The research team uncovered records that 2.59 tonnes of scales, representing approximately 4,870 pangolins, along with 259 intact pangolins (220 living; 39 dead) have been seized since 2010, resulting in 43 enforcement cases.
There are eight species of pangolin, four of which are found in Asia and four of which live in Africa.
Chinese and Sunda pangolins are listed as Endangered by the International Union for the Conservation of Nature. Indian and Philippine pangolins are considered Near Threatened, as are Africa's giant and white-bellied species.
The animals roll into a ball for protection but this only makes it easier for poachers to collect and transport them unnoticed.
In traditional Chinese medicine, roasted pangolin scales are thought to detoxify and drain pus, relieve palsy, and stimulate lactation.
Rapid economic growth in Asia has resulted in soaring demand in recent years.
Pangolins by post
In addition to smuggling whole animals, traffickers use the postal system to transport their contraband.
In the report, Prof Macdonald and colleagues highlight that last November, Beijing customs officials intercepted five parcels of pangolin scales weighing 70kg each.
They subsequently discovered a further tonne of scales had been shipped in this way since April, the equivalent of 1,660 individual animals.
Prolific smugglers have received prison sentences from 11 years to life but with demand out-stripping supply, the trade is only becoming more lucrative.
According to the report, pangolin scales are currently worth £360 ($600) per kilo, twice the amount they traded for in 2008.
Poor old pangolins are a bit of a forgotten species'
End Quote Richard Thomas TRAFFIC, the wildlife trade monitoring network
Pangolins only give birth to one offspring per year and conservationists warn that current declines are unsustainable.
Richard Thomas, from the wildlife trade monitoring network TRAFFIC, described the animals as 'overlooked' in comparison with the more 'charismatic' targets of smugglers.
'Poor old pangolins are a bit of a forgotten species. There's been a lot of attention to the big iconic animals: elephants, rhinos, tigers but not much attention to pangolins.'
He explained that Asian species of pangolin are protected under CITES legislation and have a 'zero quota', meaning their removal from the wild for international trade is illegal.
TRAFFIC staff in Asia are helping to train customs and postal workers to help them detect smuggling attempts and raise awareness of the animals' plight.
'We've uncovered a disastrous situation and currently all the omens for the pangolin are bad but hopefully by drawing attention to this useless trade, international opinion may contribute to changing the situation of the pangolin,' said Prof Macdonald.
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