The St. Bernard is known for rescuing humans in the mountains but now a human has come to the rescue of a St. Bernard.

The incredible story begins when a Calgary firefighter went on vacation in British Columbia.

Dave and his girlfriend Sandy found the St. Bernard at the bottom of a ravine in the backcountry at Josephine Falls.

"I start whistling and she lifts up her head, looks around and flops down...so I scrambled down," says Dave.

The female dog was about 91 metres (300') at the bottom of a steep, loose rock cliff.

When Dave reached the bottom, he knew the dog was in dire straights. "She came to me but she was so skinny and weak and she was shaking and then she just flopped down."

The couple had to leave the crying dog behind and raced to Elkford to get help. Some locals and a couple of volunteer firefighters answered their call. When they returned, the dog had somehow managed to claw her way out of the ravine and they found her collapsed on the grass.

With no collar, tattoo or micro chip, Dave checked with locals, the RCMP and SPCA shelters in Cranbrook and Blairmore but nobody had reported a lost St. Bernard.

Dave didn't want to leave the dog behind so he brought her home to Calgary and has named her Jo.

Once back in the city, they went to a vet and Jo was treated for malnourishment, dehydration and a serious infection.

Jo has had surgery and is now recovering at her new home with Dave and she seems indebted to her rescuer. "If I get up to go outside, she's right behind me. She doesn't want to be left alone so I'm just going to spoil her for a bit but she's worth it," says Dave.

Dave says the story has touched all his friends so much that they are lined up to help care for her when he's at work.