(CNN) Trapped by the sharp claws and teeth of a mountain lion, a runner fought hard for his life. To break free, wildlife officials said, he choked the animal to death.

A man was running by himself Monday in the Horsetooth Mountain Open Space near Fort Collins, Colorado, when he heard something behind him. When he turned around, an 80-pound mountain lion attacked him, Colorado Parks and Wildlife officials said.

The young lion bit the runner's face and wrist but he managed to break free and kill the lion in self-defense, the agency said.

A necropsy confirmed the animal was suffocated, officials said Tuesday. The lion, which was less than a year old, tested negative for rabies, CPW tweeted.

"The runner did everything he could to save his life. In the event of a lion attack you need to do anything in your power to fight back just as this gentleman did," said Mark Leslie, Colorado Parks and Wildlife's northeast region manager.

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