Guo had gone on a hike in late January while visiting his hometown of Yichang in central China's Hubei province.

When reviewing the photos, he saw something he had not noticed before: a mountain shaped like a dog's head rested on the ground next to the Yangtze River, its snout perched at the water's edge.

"It was so magical and cute. I was so excited and happy when I discovered it," Guo said.

"The puppy's posture is like it's drinking water or it's looking at some fish. It also looks like it's quietly protecting the Yangtze River," he said.

Guo's post on Chinese social media app Xiaohongshu, or RedNote, received 120,000 likes within 10 days.

The hashtag #xiaogoushan - Chinese for "Puppy Mountain" - drew millions of views on the media platform Weibo.

Dog owners began posting pictures of their dogs to see which one had the closest resemblance.

Many people travelled directly to the location in Yichang to see the mountain, and some even brought their dogs to take photos.

"Puppy Mountain here I am!" one social media user wrote on RedNote along with photos of the mountain.

"Just stroke the puppy's head, and then everything will be OK."

The mountain is in Yichang's Zigui County, where it can be seen from an observation deck.

The Yangtze River, the longest river in China and the third-longest river in the world, flows through the mountainous area.

After Guo's photo went viral, many people shared photos of the view they previously had taken from the same deck, many saying they had not realised it looked like a dog.

Some discussed how the dog's appearance has changed over the years.

Yichang resident Shi Tong said he had seen the mountain before and posted a photo he took of it in 2021.

"After I saw the Puppy Mountain photo online, I tried to look up where it is. And then I realised that I have been to this place before. I thought it looked like a dog at that time, too."

With AAP.