About 4,000 years ago,Bactrian camels were domesticated.

大约4000多年前们驯化了双。

But it is the only source of water, so Bactrian camels eat it.

可是这是唯一水源，所以双只能吃雪。

So Ganbold and his twin-humped Bactrian camels must chase the snow towards the mountains where it lingers.

所以冈包勒德和他双必须循着雪花，向着它们所山脉赶去。

This extraordinary performance is a male Bactrian camel's way of attracting the attention of a passing female.

这种奇怪表演是公双吸引路过母骆一种方式。

China is one of the main habitats for Bactrian camels in the world, but the ancestral home of camels is in North America, far away.

中国是世界上双主要栖息地之一但骆祖籍却在遥远北美洲。