A prejudice or exceptionalism exhibited by one species (typically humans) with regard to another species (typically animals in general). The term was first used by British psychologist Richard Ryder in 1973 and has since been adopted by a large number of critics, most notably animal rights campaigner Peter Singer. Generally speaking, the charge of speciesism is made wherever and whenever the rights humans enjoy are not extended to other species---in particular, this implies the right of animals not to be kept in captivity, eaten, or experimented upon. The key issue is whether or not humans are morally and ethically justified in regarding themselves as a superior species with a sovereign right to treat all other earthly creatures as resources. As one might expect, opinion is divided quite sharply on this issue.