Yet Heidi appears to be the next in a line of animal celebrities in Germany. The 2-1/2-year-old opossum has a growing Facebook following pushing 80,000 fans, sparked a popular song on YouTube and will soon star as a plush toy. However, the public will not get their first glimpse of the opossum until July, when the zoo opens its tropical wildlife exhibit.
The zoo had no inkling of what a cause-celebre the cross-eyed opossum would become when Heidi along with her sister, Naira, and a male opossum arrived from a zoo in Denmark in May.
"The Heidi sensation was surprising and unplanned," said Leipzig zoo spokeswoman Maria Saegebarth. "It's great that there has been a lot interest, but we had nothing to do with the media hype."
Heidi first appeared in Germany's mass-circulation newspaper Bild last month. The zoo has no plans to change its upcoming tropical exhibit because of Heidi's ticket draw.
"We understand that Heidi has become so popular and that people will want to see her," said Saegebarth. "But that will not change the zoo's strategy with the exhibit -- she's one animal of many."
Still, Heidi is the most recent example of animal celebrities in Germany in recent years, which includes Knut the polar bear in Berlin and the recently deceased Paul the octopus in Oberhausen, western Germany.
Knut became internationally famous as a cub when the Berlin zoo hand-reared him after he was rejected by his mother in December 2006. The zoo earned 1 million euros ($1.30 million) from marketing Knut products in 2007.
Paul the octopus was an international sensation this past summer when he correctly predicted the results of each of Germany's World Cup soccer matches and accurately tipped Spain to top the Netherlands in the final.
Demand for information about Heidi has been so high the zoo has dedicated a portion of its website to answering Heidi-related questions, such as why she is cross-eyed.
Zoo officials believe that Heidi's crossed eyes could come from a poor diet when she was young, causing fat deposits to develop behind her eyes -- neither of which causes her pain or poses a health risk, the zoo said.
Poor vision is not much of a problem for Heidi, the zoo said. As a nocturnal animal, opossum's rely heavily on their sense of smell instead of their sight to get around.