Speciesism is thinking that humans are better than animals (although humans are technically also animals). It is also treating animals worse than humans. For example, humans often kill animals to eat. Humans rarely kill and eat other humans. The word 'speciesism' was first used in 1970 by Richard D. Ryder, an English philosopher, in a pamphlet called "Speciesism". It was made popular by Peter Singer's 1975 book "Animal Liberation". In the book the name of the fifth chapter was "Man's Dominion ... a short history of speciesism". The word 'speciesism' was first put in the "Oxford English Dictionary" in 1985.