An SPCA is an organization dedicated to the prevention of cruelty to animals. The oldest SPCA in the world is Britain's Royal Society for the Prevention of Cruelty to Animals, founded in 1824. The American Society for the Prevention of Cruelty to Animals was founded in New York in 1866. The ASPCA has played an integral role in the humane treatment of animals in New York since that time. Other SPCAs or Humane Societies exist through out the US. There is no national body named SPCA in the US akin to the RSPCA .
SPCAs often operate animal shelters. Stray or disowned animals are looked after prior to finding a new home. In some instances animals may be put down or destroyed if they can not be found a home. This is often controversial and has lead to many SPCAs adopting a policy of no euthanasia; such as the Texas SPCA .
SPCAs have a history of advocating animal rights since the 19th century. In previous times animals were treated with extreme cruelty and neglect. The institutional role of an SPCA is sometimes at odds with the more activist nature of other Human Societies.