Beginning in 1960, Glynn Riley trapped for the Texas Rodent and Predatory Animal Control Service, a cooperative program involving the U.S. Fish and Wildlife Service and the Texas Animal Damage Control Association. In the course of his career, he worked on control of a variety of animals considered a threat – including rats, pocket gophers, bobcats, red foxes, coyotes, and alligators. He is especially remembered for his work capturing the last red wolves from the wild.