He performed in places like Madison Square Garden more times than Frank Sinatra, Jack Dempsey and lots of other big names. But after 11,697 shows, animal trainer Gunther Gebel-Williams performs his last death-defying act Sunday with the Ringling Bros. and Barnum & Bailey Circus. ``Everybody asks me, `Why now?''' he said in the thick German accent he hasn't lost since he came to the United States 22 years ago. ``I want to step down when I am really good. I don't want to be like Ali, Sugar Ray, `Another fight, another fight.' '' A U.S. citizen since 1979, he calls himself ``German-engineered but a proud American'' and often sports a cowboy hat and a Western-style shirt. Though he's 56, Gebel-Williams remains enviably trim, 141 pounds with a ruddy complexion and his trademark sweep of blond hair. He announced two years ago that he would retire from ``The Greatest Show on Earth'' at the end of the 1990 season. He plans to settle at his winter home in Venice, Fla., with his 20 Bengal and Siberian tigers. After 42 years on the road, he said, training 20 tigers is getting a little riskier because he has lost some of his quickness and his eyesight is not what it used to be. And glasses wouldn't look so hot with his skin-hugging tights and sequined boleros, he joked. ``When you have 20 tigers, it's not easy to act like nothing can happen,'' he said. ``I've been like their father, their brother. I've been in charge always. But when one tiger is hurt, they always blame me.'' His domination in the ring comes from a soft-spoken training method based on mutual respect that separates him from his chair-and whip-wielding predecessors like Clyde Beatty and Mabel Stark, who taught animals to fear them. Gebel-Williams strokes his elephants' trunks, pats the tigers and mumbles commands in German, Indian or English. He welcomes animal rights advocates to attend his training sessions. ``That's the difference between me and everybody else,'' he said. ``I did everything with open doors. ``In 21 years never did somebody say I treated an animal wrong.'' Gebel-Williams began his career when he joined Circus Williams in Germany as an usher at 12. He became so much a part of the Williams family, who had hired his mother as a seamstress, that he added their name to his. By the 1960s, he was well-known as one of Europe's top animal trainers. In 1968, he caught the eye of Irvin Feld, owner and producer of Ringling Bros. and Barnum & Bailey Circus, who bought the entire Circus Williams to get their star to come to America. Now Gebel-Williams will yield the ring to his 20-year-old son, Mark. But he won't yield the tigers because he's afraid they won't transfer their devotion to his son. Mark's act will include the African and Indian elephants, white Lippizaner horses, zebras and camels. ``I think it's time for Mark. I have to step back,'' said Gebel-Williams, adding that he'll continue to work with the animals behind the scenes. Gebel-Williams said he didn't plan anything special for his last show, explaining that a change in routine would confuse the animals. And he hopes no one calls for a speech. ``It'll be very tough, but as long as I don't have to talk I can get through it,'' he said. After a lifetime with the circus, it would be impossible for him - and his tigers - to give it up entirely, he said. ``I believe some of my tigers will miss this. Maybe once in a while, I'll take them in the ring in Venice, turn on the music real loud, and let them pretend.''