Siling Co

Siling Co

Siling Co is the largest lake in Tibet and the second-largest saltwater lake in China. It is a tectonic lake formed during the uplift of the Tibetan Plateau and is also a large deep-water lake, with depths exceeding 30 meters in the central area, water transparency of 7–8 meters, and a salinity of 18.3–18.8 grams per liter. Every summer, the lake’s small islands are home to a wide variety of migratory birds.

In Tibetan, Siling Co means "the Demon Lake that Reflects Glorious Light." It is located in Bangor County and Shenzha County at the northern foot of the Gangdise Mountains. The lake stretches 72 kilometers from east to west and about 22.8 kilometers from north to south, with the eastern part reaching a maximum width of 40 kilometers.

As of June 2014, Siling Co covered an area of 2,391 square kilometers, surpassing Namtso by 369 square kilometers to become China’s second-largest saltwater lake. The lake surface sits at an elevation of 4,530 meters, with a maximum depth of over 33 meters. Major inflowing rivers include the Zhaga Zangbo, Zagan Zangbo, and Boqu Zangbo. According to scientists, Siling Co once spanned 10,000 square kilometers, but due to climate change, the lake shrank, giving rise to separate lakes such as Gering Co, Cuoe Co, Yagadong Co, Bangg Co, Wu’er Co, Qagu Co, Zigui Co, and Yueqia Co.

The Siling Co basin is surrounded by mountains, with a vast lake basin and lush lakeside grasslands. It serves as one of the important pastoral areas in northern Tibet and is also part of the Shenzha Wetland Nature Reserve, which protects the black-necked crane and its breeding ecosystem. The lake is dotted with mountains, and the mountains encircle the lake, creating a scene of captivating beauty. The blue-green hues of the lake even overshadow the azure sky. Legend has it that King Gesar fought the demon king Arjung, who, after being defeated and suffering from unbearable thirst, begged to drink his fill even in death. King Gesar beheaded Arjung and threw his head into Siling Co so he could drink forever. Since then, no matter how many rivers flow into it, the lake has never overflowed.

Legend says that Siling was a great demon who once lived in Duilongdeqing, west of Lhasa. Every day, he greedily devoured millions of lives, including humans and all kinds of animals. No one could stand up to his tyranny. On a fine day after a thunderstorm, the demon-slaying Guru Rinpoche finally found

Siling. How could Siling possibly defeat the master? Thus, under the relentless pursuit of Guru Rinpoche, Siling fled to a vast, murky lake south of the Gangnyi Qiangtang. The master commanded Siling to never leave the lake, to repent devoutly within it, to refrain from harming aquatic life, and named the lake “Siling Dui Co,” meaning “Siling Demon Lake.” This is the story of Tibet’s only two “devil lakes.”

Siling Co is home to the highest number of rare and endangered species in the high-altitude cold steppe ecosystem and is the world’s largest nature reserve for the black-necked crane. Other protected animals include the nationally first-class protected species: black-necked crane, snow leopard, Tibetan antelope, argali, Tibetan wild ass, and Tibetan snowcock. The Siling Co naked carp (Gymnocypris selincuoensis) is the only fish species found in this lake in northern Tibet.

In 1985, Siling Co was designated as a regional-level nature reserve in the Tibet Autonomous Region and was elevated to a national nature reserve in 2003. The lake is currently facing issues such as desiccation, mineralization, and shrinking surface area. The government has taken careful measures to protect the local environment during development and construction. For example, during the construction of the Qinghai-Tibet Railway, workers stacked over 240,000 sandbags filled with gravel along one side of Siling Co to create a nearly 20-kilometer-long protective “Great Wall,” separating the lake from the bustling construction site.

Siling Co is a kingdom of lakes, surrounded by 23 satellite lakes like a string of emerald necklaces. It is said that millions of years ago, these were all part of a single vast lake. Among these satellite lakes, the bird island of Cuoe Co has become a secondary haven for migratory birds. Every spring and summer, tens of thousands of Mediterranean gulls can be seen flying here from the Mediterranean Sea—a truly spectacular sight. These gulls are similar to those seen at Bangong Co, with slender red legs, pointed red bills, entirely white feathers except for their wings and tails, which are grayish-white, and gentle temperaments that make them unafraid of humans.