Two B.C. men are in hospital after fighting off a bear who attacked them Wednesday morning during a camping trip on Vancouver Island.

A 57-year-old man was sleeping in a lean-to shelter around 7 a.m. in an area known as Taylor Flats at the west end of Sproat Lake, near Port Alberni, when a bear started clawing at him.

In Pictures: B.C. men survive bear attack

His 47-year-old companion, sleeping in a tent nearby, woke up and sprung into action when he heard the attack.

He was able to fend off the 150-pound animal.

"He was able to grab hold of the bear or just push it aside and get it off of his friend," Sgt. Kevin Murray told ctvbc.ca.

Both men received extensive claw wounds. The older victim also sustained serious injuries to his skull.

The pair drove to hospital in Port Alberni, approximately 50 kilometres away, and alerted police. The 57-year-old was transported to Nanaimo for surgery.

Sgt. Murray said the men had seen the bear around their camp on the first day of their trip but they chose to stay.

"Most people would just leave," he said.

"Some people are not deterred by bears but when you're camping in an open air enclosure you're taking a risk."

Murray said the area is often frequented by bears. Authorities still don't know what prompted the attack.

Officers with the B.C. Conservation Service and the RCMP planned to return to the campsite Wednesday afternoon.