It's been 40 years since the former public health expert accidentally discovered the Ili pika while on a mission to discover the source of plague foci in the Tianshan Mountains. Looking back, he's filled with emotion.

"I discovered the endangered species. If I don't protect it and it becomes extinct, I'll be the one to blame," he says.

The Ili pika is a small, fluffy mammal, around 20 centimeters long, with bright fur, big round ears and brown mottled fur on its forehead and neck. It impresses people with its beauty and cuteness.

It looks like a cross between a rabbit and a mouse, but actually belongs to the Lagomorpha order. Among the world's 30 pika species, it has the largest ears, longest hind feet and largest body size.

It's endemic to the bare rocks located between 2,800 and 4,100 meters above sea level in the Tianshan Mountains. It lives alone, doesn't drink water, but eats rare alpine plants, including snow lotus and Rhodiola rosea (roseroot stonecrop).

When the Ili pika was formally recognized as a new species in 1986, Li estimated that there were around 3,000 of them. At first, experts thought that keeping a low-profile to minimize human influence would benefit the creature's preservation.

However, when Li traveled around the area in 2002, he became anxious that the species had lost half of its habitat. Since then, he has systematically investigated the population of Ili pika every four years, mainly by tracking their spoor and monitoring their food storage.

Over the years, among the 14 monitoring points in the Tianshan Mountains, they have only discovered a few new trails and food stores, mainly at Glacier No 1 on the headwaters of the Urumqi River and in Jinghe county, Bortala Mongolian autonomous prefecture.