The forest guard, identified as Anand Singh, was on night patrol. He was apparently attacked by the feline when he was returning from duty to his residence.
His body was recovered on Friday morning after his family members raised an alarm as he did not reach home.
The patrol parties of the forest department began combing the area and his clothes and slippers were found soaked in blood near a bridge and the badly mauled body was found lying nearby.
Senior forest officers, including the Firector of the Rajaji Tiger Reserve, rushed to the scene of the incident and the body has been sent for post-mortem examination, said an official.