Scientific basis for the myth of the jackalope
trib.com
"There is a virus that causes growths on the jack rabbit," Holliday said. The virus is called Shope papillomavirus. Growths can come out of rabbits' bottoms and heads. When they grow from the head, they can look like horns. Holliday described a rabbit that had a growth on its mouth. "The poor thing starved to death," he said. Holliday's jackalope website, which he runs with colleague Dan Japuntich, features photos of rabbits with Shope papillomavirus and even people with growths that look like horns. Scientists believe the virus was in North America for centuries, but showed up in Europe shortly after Christopher Columbus returned from his voyage to the New World.