Roy and Silo (born 1987) were two male chinstrap penguins in New York City's Central Park Zoo. They were noted by staff at the zoo in 1998 to be performing mating rituals, and one of them in 1999 attempted to hatch a rock as if it were an egg. This inspired zoo keepers to give them an egg from a pair of penguins, which could not hatch it, resulting in both of them raising a chick that was named Tango. Tango herself was viewed in a similar situation with another female penguin. Roy and Silo drifted apart after several years, and in 2005, Silo paired with a female penguin called Scrappy. Roy and Silo's story has been made into a children's book and featured in a play. The practice of allowing pairs of male penguin couples to adopt eggs has been repeated in other zoos around the world. Both Tango and Roy have since died. History Roy and Silo met at the zoo and they began their relationship in 1998. They were observed conducting mating rituals typical of their species including entwining their necks and mating calls. In 1999 the pair were observed trying to hatch a rock as if it were an egg. They also attempted to steal eggs from other penguin couples. When the zoo staff realized that Roy and Silo were both male, they tested them further by replacing the rock with a dummy egg made of stone and plaster. As it was "incubated real well", it occurred to the zoo keepers to give them the second egg of a penguin couple, a couple which previously had been unable to successfully hatch two eggs at a time. Roy and Silo incubated the egg for 34 days and spent two and a half months raising the healthy young chick, a female named "Tango". When she reached breeding age, Tango paired with another female penguin called Tanuzi. As of 2005, the two had paired for two mating seasons. Shortly after their story broke in the press, Roy and Silo began to separate after a more aggressive pair of penguins forced them out of their nest. In 2005, Silo found another partner, a female called Scrappy, which had been brought from SeaWorld Orlando in 2002, while Roy remained single. Both Tango and Roy have since died. Impact Roy and Silo were not the first same-sex male penguin couple to be