Theory:

     According to his theory, a tiger starts eating humans, when they grow old or get hurt. As, they can not run fast, they start killing humans. People can not run as fast as animals, so they become easy prey. After eating human flesh once, a tiger will not eat any other flesh. These tigers are called man-eaters.
 
     His first, man eating tiger hunt was, The Champawat Tiger. It was a Bengal tigress responsible for nearly 436 deaths in Nepal and the Kumaon area of India. Her attacks have been listed in the Guinness Book of World Records as the highest number of fatalities from a tiger. She was shot in 1907 by Jim Corbett.
Explanation:
 
According to Jim, a tiger hunts other animals only. But when it grows old or if it gets hurt, it cannot run fast. So it cannot hunt other animals. As humans cannot run as fast as other animals, humans are an easy target for old/hurt tigers. If a tiger eats human flesh once, it will not eat any other animal's flesh. Such tigers are called man-eaters.
 
The first man-eating tiger hunted by Jim was The Champawat Tiger. The Bengal tigress had attacked neatly \(436\) people in Nepal and the Kumaon area in India. Following the deaths of \(436\) people, it was listed in the Guinness Book of World Records as the highest number of deaths by accident, from a tiger. She was shot dead by Jim in \(1907\).
  
Meanings of difficult words:
  
Words
Meanings
preyan animal that is killed by another animal, for food
fatalitiesan occurrence of death by accident
shotkilled by firing a gun or canon
Reference:
State Council of Educational Research and Training (2019). Term-1 English Standard-8. Jim Corbett, A Hunter Turned Naturalist(pp. 99-102). Published by the Tamil Nadu Textbook and Educational Services Corporation.