"Our goal this year is to create an online adoption service, a mini-program on WeChat, in which our activities come into their own, and we sift out the scammers and cat dealers. Most importantly, we want to set up a screening protocol and help adopters we are unable to help elsewhere in the country."

As he has made hundreds of videos about saving cats, it dawned on him that unscientific pet raising and problems with stray animals often start with someone deciding on a whim to have a pet, ignorant of the responsibilities this involves.

The idea of raising pets being an emotional support for people has turned into an attractive business proposition that has led to overbreeding, which, Xu says, makes it all too easy to obtain a pet at little cost.

"I want to make some more popular and interesting science videos to deal with the root of the problem and to show people how to treat animals in a methodical and logical way.

"As our videos become popular we receive many messages every day, and we tell about how stray cats can be looked after properly. You can't just feed stray animals in a haphazard way, and by sterilization and adoption we are slowly coming to grips with this problem."

Those who admire what Xu is doing have nicknamed him the Cat Fighter, and the reason for that is clear from the many exploits he has had plucking cats from peril and even the jaws of death. These include: saving a dying cat trapped in a 10-meter deep elevator well; retrieving a tabby cat from a sewer after it had not eaten for almost a week; plucking to safety a stray cat trapped in a tree 20 meters high.

In the video, Xu, wearing rimmed black glasses, looks bookish, yet he has much more dexterity than someone who simply turns pages. He is strong and often needs to be faster and even more nimble than the cats he is trying to save.

After a tip-off is received he hits the road, and if all goes well, returns with the rescued cat to the center, where the recovery mission continues, the fortunate cat receiving copious doses of attention as well as food and any other physical help it may need. Though there is a common thread running through his routine-hear, go and seek, find, bring back to the center-Xu has myriad workplaces, whether it be the roof of a shed, the outer wall of a high-rise building, the deep well of an elevator, or a sewer next to a river.