Tiger attacks are an extreme form of human–wildlife conflict which occur for various reasons and have claimed more human lives than attacks by any of the other big cats. The most comprehensive study of deaths due to tiger attacks estimates that at least 373,000 people died due to tiger attacks between 1800 and 2009 averaging about 1800 kills per year, the majority of these attacks occurring in India, Nepal and Southeast Asia. Reasons for attacking If a human comes too close and surprises a sleeping or feeding tiger, or a tigress with her cubs, the tiger will attack and injure or kill. Tigers also attack humans in a case of "mistaken identity" (for example, if a human is crouching while collecting firewood, or cutting grass) and sometimes when a tourist gets too close. Some also recommend not riding a bicycle, or running in a region where tigers live, in order to not provoke their chase. Peter Byrne wrote about an Indian postman who was working on foot for many years without any problems with resident tigers, but was chased by a tiger soon after he started riding a bicycle for his work. While on average there are approximately 85 or fewer people killed and injured by tigers each year, India has seen sharper increases in tiger attacks, as was the case in 2014 and 2015 due to urban expansion into the tiger's natural habitat. Many human fatalities and injuries are due to incidents at zoos, or to the man-eating tigers in India. In some cases, tigers will change their natural diet to become man-eaters. This is usually due to a tiger being incapacitated by a gunshot wound or porcupine quills, or some other factors, such as health issues and disabilities. In such cases, the animal's inability to take traditional prey forces it to stalk humans, which are less appetizing, but much easier to chase, overpower and kill; this was the case with the man-eating tigress of Champawat, which was believed to have begun eating villagers at least partially in response to crippling tooth injuries. As tigers in Asia often live in close proximity to humans, tigers have killed more people than any other big cat. Between 1876 and 1912, tigers killed 33,247 people in British India. Man-eaters have been a recurrent problem in India, especially in Kumaon, Garhwal and the Sundarbans mangrove swamps of Bengal. There, some healthy tigers have