In the pristine forests along the China-Vietnam border, a group of eastern black-crested gibbons (the Cao Vit Gibbon) thrive. Once widely distributed across southern China and northern Vietnam, this species was internationally recognized as extinct in the 1950s. However, at the beginning of this century, the eastern black-crested gibbon, which had been missing for nearly half a century, was rediscovered along the China-Vietnam border. This led to the initiation of cross-border cooperation between south China's Guangxi Zhuang Autonomous Region and Vietnam to protect these gibbons.

The habitat of the eastern black-crested gibbons spans the Bangliang Gibbon National Nature Reserve in Baise City, Guangxi Zhuang Autonomous Region, China, and Cao Vit Gibbon Conservation Area in Trung Khanh District of Cao Bang Province, Vietnam. Continuous landscapes connect these two reserves. China and Vietnam jointly formulated a series of plans and conducted joint surveys to protect the ecosystem on which these gibbons rely. As a result, over 3,100 mu (approximately 205 hectares) of gibbon habitat has been restored.

The eastern black-crested gibbon is a first-class state-protected wild animal in China and is also recognized by the International Union for Conservation of Nature (IUCN) as "Critically Endangered."

Currently, the population of eastern black-crested gibbons in the Chinese reserve has grown from 19 at the time of discovery to 36, achieving the goal of stable population growth from the brink of extinction. The cross-border cooperation between China and Vietnam to protect the eastern black-crested gibbons serves as a model for biodiversity conservation.