Photos: Siegfried & Roy through the years UNSPECIFIED - CIRCA 1970: Photo of Siegfried & Roy Photo by Michael Ochs Archives/Getty Images (Michael Ochs Archives)
Photos: Siegfried & Roy through the years La chanteuse française Mireille Mathieu posant avec les magiciens Siegfried et Roy au Etats-Unis, en octobre 1977. (Photo by Patrice PICOT/Gamma-Rapho via Getty Images) (Patrice PICOT)
Photos: Siegfried & Roy through the years THE TONIGHT SHOW WITH JAY LENO -- Episode -- Pictured: (l-r) Exotic animal performers/magician' Siegfried & Roy's Roy Horn, host Jay Leno on November 18, 1992 -- (Photo by: Alice Hall/NBCU Photo Bank/NBCUniversal via Getty Images via Getty Images) (NBC)
Photos: Siegfried & Roy through the years LAS VEGAS - JUNE 30: Magicians Siegfried Fischbacher (L) and Roy Horn arrive at the gala premiere of "The Beatles LOVE by Cirque du Soleil" at The Mirage Hotel & Casino June 30, 2006 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images) (Ethan Miller)
Photos: Siegfried & Roy through the years FILE - This is a Thursday, June 12, 2008 file photo of Siegfried Fischbacher, left, and Roy Horn, of the illusionist team Siegfried & Roy, as they play with a six-week-old white-striped tiger cub at their Las Vegas home. Siegfried and Roy have retired for good, but miss their fans. Siegfried Fischbacher is quoted in the Tuesday Jan. 5, 2010, edition of the German magazine Neues Blatt as saying that "Roy and I miss our audience. But there will not be a comeback." (AP Photo/Louie Traub, File) (Louie Traub)
Photos: Siegfried & Roy through the years Siegfried Fischbacher and Roy Horn during Opening Night For "Spamalot" At The Wynn Las Vegas - Arrivals at Wynn Hotel & Casino in Las Vegas, Nevada, United States. (Photo by Bruce Glikas/FilmMagic) (Bruce Glikas)
Photos: Siegfried & Roy through the years LAS VEGAS, NV - SEPTEMBER 12: Siegfried Fischbacher (L) and Roy Horn speak during Criss Angel's HELP (Heal Every Life Possible) charity event at the Luxor Hotel and Casino benefiting pediatric cancer research and treatment on September 12, 2016 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images) (Ethan Miller)
Photos: Siegfried & Roy through the years Siegfried, right, and Roy, Las Vegas magicians, pose in New York, June 4, 1987 with their rare white tigers, Neva, left, a female, and Vegas, a male, during a stop at Van Cleef & Arpels jewelry before their departure for Germany. The tigers, who were to be exhibited in Germany disappeared in their rented van Thursday and were recovered hours later in the Bronx Borough of New York City. (AP Photo/Scott McKiernan) (Scott McKiernan)
Photos: Siegfried & Roy through the years LAS VEGAS - FEBRUARY 20: Siegfried Fischbacher (L) and Roy Horn of the illusionist duo Siegfried & Roy arrive at the after party for the premiere of Bette Midler's new show, "The Showgirl Must Go On" at the Pure Nightclub at Caesars Palace February 20, 2008 in Las Vegas, Nevada. Midler will perform 100 times a year at The Colosseum at Caesars for at least the next two years. (Photo by Ethan Miller/Getty Images for AEG Live/Concerts West) (Ethan Miller)
Photos: Siegfried & Roy through the years Die aus Deutschland stammenden amerikanischen Magier und Dompteure Siegfried Fischbacher (l) und Uwe Horn, alias Roy (r), aufgenommen im Frühjahr 1981 in Las Vegas. (Photo by Horst Ossinger/picture alliance via Getty Images) (picture alliance)
Photos: Siegfried & Roy through the years UNITED STATES - DECEMBER 01: Siegfried and Roy in Las Vegas, United States on December 01, 1993. (Photo by Alain BENAINOUS/Gamma-Rapho via Getty Images) (Alain BENAINOUS)
Photos: Siegfried & Roy through the years Siegfried & Roy, Homestory, Las Vegas/Nevada/USA, Suite im Hotel "The Mirage", Künstlernamen, Siegfried Fischbacher, Roy Uwe Ludwig Horn, Magier, Magierduo, Illusionisten, Illusionistenduo, Promis, Prominente, Prominenter, (Photo by Peter Bischoff/Getty Images) (Peter Bischoff)
Photos: Siegfried & Roy through the years LAS VEGAS, NV - OCTOBER 22: Siegfried Fischbacher and Roy Horn celebrate SARMOTI Cubs day with Make-A-Wish Foundation at The Mirage Hotel & Casino on October 22, 2015 in Las Vegas, Nevada. (Photo by Denise Truscello/WireImage) (Denise Truscello)
Photos: Siegfried & Roy through the years Siegfried & Roy, "Stars und Sensationen", zum 25-jaehrigen Jubilaeum des Phantasialands, 18.06.1991, Künstlernamen, Siegfried Fischbacher, Roy Uwe Ludwig Horn, Magier, Magierduo, Illusionisten, Illusionistenduo, Promi, Promis, Prominente, Prominenter, RX; Foto: P.Bischoff; Veröffentlichung nur gegen Honorar und Beleg! (Photo by Peter Bischoff/Getty Images) (Peter Bischoff)
Photos: Siegfried & Roy through the years LAS VEGAS, NV - APRIL 26: Siegfried Fischbacher (L) and Roy Horn attend the 18th annual Keep Memory Alive "Power of Love Gala" benefit for the Cleveland Clinic Lou Ruvo Center for Brain Health honoring Gloria Estefan and Emilio Estefan Jr. at the MGM Grand Garden Arena on April 26, 2014 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images for Keep Memory Alive) (Ethan Miller)
Photos: Siegfried & Roy through the years Siegfried & Roy mit einem weiÃen Tiger,;Homestory "Dschungel-Palast", Las Vegas, Nevada, USA, Tiger, Tier, Künstlernamen, Siegfried Fischbacher, Roy Uwe Ludwig Horn, Magier, Magierduo, Illusionisten, Illusionistenduo, Promis, Prominente, Prominenter, (Photo by Peter Bischoff/Getty Images) (Peter Bischoff)
Photos: Siegfried & Roy through the years Heino, Hannelore Kramm, Zauberduo "Siegfried und Roy", Stardust-Hotel, Las Vegas, Nevada, Amerika, Verkleidung, getönte Brille, Sonnenbrille, Schlager-, Volksmusik-Sänger, LG/PH, 15.05.1978; (Photo by Peter Bischoff/Getty Images) (Peter Bischoff)
Photos: Siegfried & Roy through the years (GERMANY OUT) Siegfried Fischbacher (Siegfried), Uwe Horn (Roy) Zauber-Duo, USA, im `Phantasialand`, - 1987 (Photo by Galuschka/ullstein bild via Getty Images) (ullstein bild)
Photos: Siegfried & Roy through the years THE TONIGHT SHOW WITH JAY LENO -- Episode 1081 -- Pictured: (l-r) Siegfried Fischbacher, Roy Horn (Siegfried & Roy) during an interview with host Jay Leno on February 5, 1997 -- (Photo by: Margaret Norton/NBCU Photo Bank/NBCUniversal via Getty Images via Getty Images) (NBC)
Photos: Siegfried & Roy through the years Die aus Deutschland stammenden amerikanischen Magier und Dompteure Siegfried Fischbacher (r) und Uwe Horn, alias Roy (l), posieren im Frühjahr 1981 mit einem ihrer Tiger auf ihrem Anwesen in Las Vegas. (Photo by Horst Ossinger/picture alliance via Getty Images) (picture alliance)
Photos: Siegfried & Roy through the years Siegfried Fischbacher and Roy Horn celebrate the first birthday of five of their tiger cubs at Siegfried & Roy's Secret Garden & Dolphin Habitat at The Mirage on May 12, 2009 in Las Vegas, Nevada. (Photo by Denise Truscello/WireImage) (Denise Truscello)
Photos: Siegfried & Roy through the years Siegfried Fischbacher and Roy Horn of Siegfried & Roy (Photo by Ron Galella/Ron Galella Collection via Getty Images) (Ron Galella)
Photos: Siegfried & Roy through the years Illusionists Siegfried and Roy react after receiving the second annual Liberace Legend Award at a gala benefit at the famed Liberace mansion in Las Vegas, May 17, 1995. The two were honored for their tenure in the world of entertainment, their devotion to wildlife conservation and significant contributions to the community. (AP Photo/Lennox McLendon) (Lennox McLendon)
Photos: Siegfried & Roy through the years Siegfried & Roy, master illusionists, appear on the Radio City Music Hall stage in New York, Sept. 22, 1989, with their opening act of "creatures." Siegfried & Roy's act features rare white tigers and vanishing elephants. (AP Photo/Ed Bailey) (Ed Bailey)
Photos: Siegfried & Roy through the years LAS VEGAS, NV - APRIL 28: Siegfried Fischbacher and Roy Horn attend The Animal Foundation's 10th annual "Best in Show" at the Orleans Arena on April 28, 2013 in Las Vegas, Nevada. (Photo by Denise Truscello/WireImage) (Denise Truscello)