Jane Pauley hosts this special primetime edition of “Sunday Morning,” celebrating America’s love of animals in all shapes and sizes. Featured are stories on presidential pets; the popularity of animal videos on the internet; an interview with actor Michael J. Fox about the bond he shares with his dog, Gus; how the family of “Crocodile Hunter” Steve Irwin is carrying on his life’s mission; a look at pets that resemble their owners; the practice of pet cloning; and the Smithsonian National Zoo’s latest star, the giant panda cub Xiao Qi Ji.