On a scorching summer afternoon, a wild Siberian tiger with flamboyant orange coat and vertical black stripes is seen taking a nap in deep forests of northeast China.

Experts in the Northeast China Tiger and Leopard National Park saw the visuals through a real-time monitoring system.

While some experts predicted in 1988 that wild Siberian tigers would disappear from China in four decades, Feng Limin, a tiger expert, witnessed how China brought back the big cat from the brink of extinction.

China has launched a pilot national park project for Siberian tigers and Amur leopards, spanning an area of over 1.46 million hectares in the provinces of Jilin and Heilongjiang. Construction of the national park is scheduled to be completed this year.

Four years ago, Feng and his colleagues sank their teeth into the protection and research of Siberian tigers in the city of Hunchun, Jilin Province, a core area of the national park.

But where are the big cats? In the early days, researchers had to spend a lot of manpower to climb over mountains by feet and install infrared cameras.

"We usually spent three months replacing batteries of the cameras, three months retrieving data cards and another three months analyzing the data," said Feng, deputy director of the monitoring and research center of Siberian tigers and Amur leopards under the National Forestry and Grassland Administration.

"So the final videos and images we got were actually recorded a year ago, making it difficult to carry out the protection work efficiently," Feng said ahead of the International Tiger Day, which fell on Wednesday.

To get real-time data of the endangered animals, researchers cooperated with tech firms to set up networks in the uninhabited forest and develop intelligent infrared cameras.

The devices can relay high-definition images and videos of animals and collect data on natural resources such as soil, water and air.

"What we protect is not only a single species but also their habitats, surrounding vegetation and the complete food chain to make sure the species can survive and prosper in the environment," Feng said.

The monitoring system uses artificial intelligence to record the appearances of the animals, and big data analysis enables researchers to know the condition of different species and habitats.

The number of intelligent infrared cameras has increased to over 3,000 from more than 100 in 2018. More such cameras will be installed in the forest.

Siberian tigers, also known as Amur tigers, mainly live in Russia's Far East and northeast China. One of the world's most endangered species, about 500 Siberian tigers are believed to be living in the wild.

With the intensified protection efforts, including the introduction of a logging ban and a national park, the number of tigers has rebounded in China.

A total of 10 wild Siberian tiger cubs had been bred in the park between 2017 and 2019, park administration said.

Monitoring results show a marked increase of wild Siberian tigers and Amur leopards in the pilot park. Six Siberian tiger breeding families and five Amur leopard breeding families have been monitored, and the proportion of the young animals has reached 30 percent to 35 percent, which is an ideal population structure state, according to the park officials.

China's conservation efforts to protect wild Siberian tigers have promoted the global population restoration of this species and the expansion of its habitats, said Jiang Guangshun, executive deputy director of the feline research center at the National Forestry and Grassland Administration.