The survey team scales two snow-capped mountain passages, one of the major challenges of the trip.

Hidden within the Yarlung Zangbo Grand Canyon, one of the world's deepest river valleys, it is arguably the remotest county in China and the only one that is not connected by highway to the outside world.

It is also this inaccessibility of Medog, an area under the jurisdiction of Nyingchi prefecture in the Tibet autonomous region, that makes the region one of the richest depositories of wildlife.

To reach this treasure chest of biodiversity, a group of seven scientists recently scaled two mountain passages at more than 4,200 m above sea level.

Along their trek through snow-covered mountain slopes and 140-km long, steep forest trails, the researchers braved possible avalanches and landslides, elbowing their way through wind-toppled trees.

The scientists had to guard against venomous snakes and wild dogs. They endured leeches, mosquitoes, gadflies, fleas and bedbugs.