Man-Dog HybridA woman examines "A Young Family," a sculpture of a human-like pig and her offspring by Australian artist Patricia Piccinini, at the 50th Venice Biennale of Art in June 2003.Photographs of the sculpture circulated on the Internet in years afterward with messages suggesting—among other things—that the pictures depicted a human-dog hybrid created by an experiment gone wrong, according to the rumor-squashing website Snopes.com.The human-dog hybrid is one of many animal hoaxes perpetrated over the centuries—especially as April Fools' Day pranks.As it turns out, there's actually some human in the sculpture—Piccinini used human hair along with silicone, acrylic, leather, and timber as materials for the artwork, according to her website.In real life, scientists have already been blurring the line between human and animal by producing chimeras—hybrid creatures that are part human, part animal, National Geographic News reported in 2005. For instance, scientists at the Shanghai Second Medical University in 2003 fused human cells with rabbit eggs—reportedly the first human-animal chimeras successfully created.(Also see: "April Fools' Day Pictures: Four Historic Science Hoaxes.")

Photograph by Gabriel Bouys, AFP/Getty Images