Dr. Sigmund Walters

Beth Colman

Fred Mason

John Whipple

Nurse Strand

Dorothy Colman

Paula Dupree, the Ape Woman

Curly

Gruen

Roustabout (uncredited)

Fred Mason (in long shots) (archive footage / uncredited)

End Narrator (voice)(uncredited)

Dock Spectator (uncredited)

Cheela the Gorilla (uncredited)

Curley (uncredited)

Beth's Murdered Neighbor (uncredited)

Trapeze Artist (uncredited)

Waiter (uncredited)

Coroner (uncredited)

Small Boy (uncredited)

Sheriff (uncredited)