Ba Xi and Ying Xue have gone through two years’ intensive survival training under the watchful eyes of experts dressed in black and white panda costumes scented with the animals’ urine. The two year old bears have proven so adept at surviving in the wild they spent several days on the run avoiding rangers in their forested training sanctuary and had to be lured back with treats. Tomorrow (Thursday) both animals will be given a final veterinary check before being let loose in the Liziping nature reserve in China’s Sichuan province. Over recent months, Ba Xi and Ying Xue have been taught to forage and also how to avoid dangers posed by predators.

REUTERS Giant pandas Ba Xi and Ying Xue have gone through 2 years of survival training before being released

As many as 1,800 giant pandas survive in the wild and by merging their vanishing habitats will help them mingle and mate

One the techniques used by trainers working with pandas is confronting them with a stuffed leopard scented with big cat urine and recordings of their fearsome growls. If a baby panda sniffs instead of running away, it fails the test. Panda urine is also a requisite scent for the trainers dressed in their black and white overalls and head coverings as it stops the animals assimilating or becoming comfortable with humans. With male Ba Xi weighing 143lb and female Ying Xue at 130lb, and both in good health as they approach the age of 30 months, officials agreed earlier this month they were ready to be released.

GETTY The pandas have been taught to forage and how to avoid dangers from predators

This will be only the second time that a pair have been set loose together. There has been mixed fortunes for single releases. China’s first captive-bred panda to go wild in 2006 only survived for a year. He was killed fighting with other pandas over territory. China has cracked the problem of helping diffident giant pandas overcome their breeding sensibilities to produce generations of captive babies, with the population reaching 520 individuals, many of which are held in zoos around the world. Yet to keep genetic diversity buoyant, China’s conservationists want to release more pandas into the wild.

GETTY The pandas were given a series of final veterinary checks before being released

Plans are in process for creating a vast reserve across 10,000 square miles of remote, bamboo-forested mountains between the cities of Chengdu and Xian by linking 70 small reserves. As many as 1,800 giant pandas survive in the wild and by merging their vanishing habitats will help them mingle and mate. Introducing captive bred animals like Ba Xi and Ying Xue is an additional bonus to helping arguably the planet’s most famous endangered animal stave off extinction. The intensive efforts of the China Conservation and Research Centre for the Giant Panda in recent years have recently seen the species reclassified from endangered to vulnerable by the International Union for Conservation of Nature, custodians of the so-called Red List.

REUTERS Workers dress in panda masks as they track pandas recently released into the wild