Image via CBS News

LOS ANGELES: A staffer at a Christian summer camp in Colorado has told of his shock at waking to find his head clamped in the mouth of a bear.

The 19-year-old survival instructor at Glacier View Ranch described his "immense pain" as he heard the black bear "crunching" on his skull.

It dragged him around 12 feet (four meters) before being scared off by other campers and is being hunted by parks officials with dogs.

"The crunching noise, I guess, was the teeth scraping against the skull as it dug in," the man, identified only as Dylan, told local news channel Denver 7.

"It grabbed me... then pulled me, and then it bit the back of my head and dragged me. When it was dragging me that was the slowest part. It felt like it went (on) forever," he added.

Dylan described feeling the bear´s breath on the back of his neck.

"There´s four spots where its claws dug into me," he told KTVB-TV, showing bite marks on the back of his head from the animal.

He had been in a sleeping bag on a lakefront alongside four other camp counsellors when the animal struck at 4:15 AM (3:15 PM PST) on Sunday in Ward, about 32 kilometres from Boulder, Colorado.

"I thought I was dreaming for a second and then I thought this hurts too bad to be dreaming," he added.

He was taken to hospital but came away with just nine staples to his head.

Colorado Parks and Wildlife told local media had not been provoked and that such attacks were uncommon.

"This is really a bear that could be a continual threat to people in this community," a spokeswoman said.