Speciesism

Speciesism () is a term used in philosophy and animal ethics for the treatment of individuals according to their species membership. The term has several definitions. Some writers define it as discrimination or unjustified treatment based on species membership, while others define it more broadly as prioritizing some species over others, regardless of whether that prioritization is justified. Richard D. Ryder, who coined the term, defined it as "a prejudice or attitude of bias in favour of the interests of members of one's own species and against those of members of other species".

The concept is used by philosophers, psychologists, sociologists and animal rights advocates to analyse differences in how humans treat non-human animals. Writers on the subject have applied it to practices including factory farming, animal slaughter, blood sports, the use of animals for fur and leather, animal testing, and the treatment of animals classified as feral or invasive. Some authors also connect speciesism with the refusal to assist animals suffering in the wild when their suffering results from natural processes.

The term first appeared in 1970 in a pamphlet by Ryder protesting against animal experimentation. It was later popularized by Peter Singer in Animal Liberation (1975). Other writers associated with the concept include Oscar Horta, Steven M. Wise, Gary L. Francione, Melanie Joy, David Nibert, Steven Best, and Ingrid Newkirk. The concept has also been criticized or rejected by writers including Carl Cohen, Nel Noddings, Bernard Williams, Peter Staudenmaier, Christopher Grau, Douglas Maclean, Roger Scruton, Thomas Wells, and Robert Nozick.