Most credited animal actor

The most credited animal actor was Trigger (USA; b. Golden Cloud), a palomino thoroughbred stallion born in San Diego, California, on 4 July 1934. Trigger made his first screen appearance in the 1938 drama Under Western Stars, where he was ridden by "singing cowboy" Roy Rogers. Trigger performed in 92 feature films between 1938 and 1959, most with his owner/rider Rogers. He was replaced by various unrelated horses all known as "Trigger Jr" after his retirement in the early 1960s, and died the day before his 31st birthday in 1965.

Many of the most-credited screen animals are other examples of so-called "wonder horses", that were closely associated with particular cowboy performers during the golden age of the B-movie western in the 1930s and 1940s. Other notable examples include Tarzan, who made 64 films as the horse of Ken Maynard between 1924 and 1940, and the original Champion, which appeared alongside Gene Autry in 51 films between 1935 and 1943.

The lengthy filmographies of these animals is partly a result of their relatively long lives – compared to dogs – but mostly a consequence of the sheer quantity of westerns that Hollywood produced in the 1930s and 1940s. During the early 1940s, Roy Rogers and Trigger would appear in five to 10 movies a year.

Pal the dog appeared in seven Lassie movies before retiring, while silent-movie wonder-dog Rin-Tin-Tin starred in 27. The lives of other, non-domesticated animals used in classic Hollywood movies were often cut short by premature deaths from illness or mistreatment. The chimpanzee Jiggs, who originated the role of Cheeta in the Tarzan series, appeared in nine films before dying at the age of nine from pneumonia (possibly related to his heavy smoking).