A part of Tibetan life for centuries, the revered animals provide food, clothing, labor and transport.
Over 40 years ago, Wu Yuchu was trapped in a blizzard in the Tibet autonomous region.
It was 1977, two years after Wu had started working in Tibet. He and more than 50 other people took shelter in a mud-brick house while the blizzard raged. The outside temperature dropped to-30 C, and food was running out.
When the rescue team finally arrived with yaks carrying lifesaving supplies, Wu immediately bonded with the beasts.
He could not have imagined that the bond would last for decades. Yaks saved his life, and he has spent most of his life promoting the animals.
"I have watched and studied them ever since," Wu says. "I grew really fond of them, and I wanted to learn more about the species." His yak studies remained a hobby until 2014, when he became the curator of the Yak Museum in Lhasa, Tibet's capital.
With a total investment of over 100 million yuan ($14.5 million), it is the country's first and only yak-themed museum.
"Now I see yaks every day, and I can tell more people about them," says the 65-year-old. He has even given himself a Tibetan name which roughly translates as "old yak man".
As the Tibetan saying goes, "Where there is a Tibetan, there are yaks". The animal has been part of Tibetan life for centuries. They provide food, clothing, labor and transport and are so revered that they are commonly used as religious symbols.
For these reasons, Wu is warmly welcomed when he goes to collect exhibits from every corner of Tibet. Locals not only donate items when Wu visits their homes, but they also trek from remote areas to Lhasa just to offer help.
The museum has also received a donation of 86 items from a Nepalese businessman. Many of its exhibits have been shown in big cities like Beijing and Guangzhou, Guangdong province. The Yak Museum is not only Wu's spiritual sanctuary, but also a place where young people can learn about their ancestors' way of life and scholars to search for different perspectives.
"Of course, one of the most frequently asked questions is 'What does yak meat taste like?'" Wu jokes.
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