Tracing the extraordinary story of the milu deer
26 October 2017
Skins dating back 150 years are revealing the story behind the near extinction of a Chinese deer species.
Père David's deer (Elaphurus davidianus), also known as the milu, are native to China but became extinct there in the twentieth century.
Captive populations kept in Europe for nearly 100 years have allowed the species to survive - but only just.
The history of this critically endangered species has been shrouded in mystery for many years.
But new research, published in the journal Royal Society Open Science, has shed some light on the milu deer's story.
Researchers analysed the DNA of deer skins in the Museum's collection and linked the origins of all surviving milu to a herd living in the southern Chinese island province of Hainan, and not northern mainland China, as was previously believed.
The results not only help to understand how the deer survived but also reveal conservation lessons for other endangered species with small populations.
Dr Samuel Turvey, the paper's lead author and Senior Research Fellow at the Zoological Society of London, comments, 'Our study provides a great example of how historical archives such as museum collections can inform contemporary approaches to wildlife conservation, while also furthering our understanding of the mechanics of extinction.'
A unique deer brought to the edge of extinction
Milu have unique, rear-facing antlers. They once roamed across most of China, but by the nineteenth century their range was drastically reduced.
All milu alive today are descended from a captive herd that lived in the Emperor's hunting grounds outside Beijing.
This royal herd was discovered by French zoologist and missionary Père Armand David, who visited China in 1861 and eventually sent some of these deer to European parks and zoos. His actions allowed the species to cling to life. The rest of the imperial herd was killed by hunters who broke into the hunting grounds in 1900, destroying the last of the deer in China.
The origins of the Emperor's herd
People have long debated the origins of the Emperor's herd. It was thought that the small population had managed to exist in captivity for hundreds of years without being restocked from the wild.
The new paper puts that theory into doubt.
The Museum holds two deer skins from Hainan Island, which lies far to the south of Beijing. They were collected in 1868. Although listed as a different species called Eld's deer, their appearance suggested that they might in fact be milu.
The research team extracted DNA from the old skins and compared it to the DNA of living milu. This not only confirmed that the skins were indeed milu but they were also genetically similar to the living animals.
The results suggest that the Emperor's herd, rather than being an isolated group, had been sourced from the wild Hainan Island deer sometime in the recent past.
Lessons for conservation
The findings underline how hard it is to maintain a successful small population of large mammals when a species is under threat of extinction. Whether the last remnants of a species are in the wild or in captive breeding programmes, they will be vulnerable.
Prof Ian Barnes, Research Leader of Ancient DNA at the Museum, says, 'Our ability to recover DNA from museum collections has greatly improved in recent years, and museums have an increasing role as storehouses of genomic information, with a positive impact on conservation efforts.'
Reintroduction into China
Over time, the Dukes of Bedford in Woburn Abbey, Bedfordshire, successfully preserved a captive population of milu. They acquired a small group of the deer between 1894 and 1903, and cared for them throughout the twentieth century.
In recent decades this herd has been used to reintroduce the milu to China. The current world population, found in zoos and nature reserves around the world, stems from this herd.
Conservationists began a programme of reintroducing the deer to China in the 1980s, where the population is now estimated to be over 5,000.
While the majority are in managed parks, a few hundred are reported to be living wild. If they were to become established, this would mark one of the few examples of a near-extinct species being successfully reintroduced into the wild.
Dr Selina Brace, Researcher of Ancient DNA at the Museum, is glad the story has a positive ending.
She says, 'The tale of the Père David's deer, and its recovery from the brink of extinction, is a classic of conservation biology. I'm delighted that we've been able to contribute to the history of this iconic species.'