Pigs still may not fly, but in one Taiwanese laboratory they glow in the dark.
A research team at National Taiwan University claims it has succeeded in breeding three male green pigs by injecting fluorescent green protein into embryonic pigs.
Partially green pigs exist elsewhere, but the Taiwanese pigs are believed to be the only ones that are green inside out, including their hearts and internal organs. In the dark, they glow bright neon green.
The pigs will reportedly be used in stem cell research and in the study of several human diseases.
The technique used by the Taiwanese scientists is fairly common. At least five years ago, a glow-in-the-dark rabbit named Alba made headlines when artist Eduardo Kac created her.
"[Alba] highlights the fact that transgenic animals are regular creatures that are as much a part of social life as any other life form," the assistant professor of art and technology at the School of Art Institute of Chicago wrote on his Web site devoted to the rabbit project.
Kac told ABC News he intended Alba's birth to spark a debate about the project itself, and about the practice of manipulating genes in animals for research. Then he hoped to adopt Alba and take her into his home with his wife and daughter. Kac said he developed the project to combine biotechnology, private family life and the social domain of public opinion into a single furry symbol.
But instead, Kac's first objective overshadowed the others. Scientists at the National Institute of Agronomic Research in France, which created the rabbit for Kac, hesitated to release the rabbit to him and his family because of protests over its creation.
Animal rights activists claimed the project, which Kac has dubbed "GFP Bunny" (for green fluorescent protein bunny), was a needless and abusive manipulation of an animal, while scientists who work with fluorescent proteins dismissed the project as interesting but silly.
"There's nothing dangerous about it, as far as we know," said Woodland Hastings, a biologist at Harvard University and co-discoverer of the jellyfish's glowing gene and its function. "But the project is rather frivolous. There are many more important things you can do with these genes."
The French scientists created Alba through a process called zygote microinjection, in which they plucked a fluorescent protein from a species of fluorescent jellyfish called Aequorea victoria. Then they modified the gene to make its glowing properties twice as powerful. This gene, called EGFG (for enhanced green fluorescent gene), was then inserted into a fertilized rabbit egg cell that eventually grew into Alba.
As the cell divided, the "green gene" also replicated and made its way into every cell of Alba's body.
Other things have been made to glow for a variety of purposes. Variations of the jellyfish's glowing genes were used in another relatively nonscientific application several years ago when a company called Prolume began to market squirt guns loaded with replicated versions of the genes. The liquid squirts like water but lights up when it comes in contact with a person or any substance containing calcium.
Other researchers are working on developing glow-in-the-dark hair mousse, ink and cake frosting. There is even preliminary research under way to produce glow-in-the-dark beer and champagne.
ABC News' Amanda Onion contributed to this report.