A peculiar phenomenon is causing a stir among residents in Fort Collins, Colorado, where rabbits with strange, black, horn-like growths have been spotted. Dubbed “Frankenstein bunnies” and “zombie rabbits” by some, these animals are infected with a virus that causes wart-like tumors, an affliction that has been the subject of scientific research for nearly a century.
According to Colorado Parks and Wildlife (CPW), the growths are caused by the Shope papillomavirus, also known as the cottontail rabbit papillomavirus. The virus, which is specific to rabbits, creates keratinous carcinomas that can resemble horns, quills, or even tentacles, primarily on the head and face. Officials stress that while the growths may look alarming, the condition is not a threat to humans, dogs, or other wildlife.
The virus is typically transmitted by biting insects like fleas and ticks, and sightings tend to increase during warmer months when these insects are more active. While the growths are usually benign and often disappear as the rabbit’s immune system fights the infection, they can become life-threatening if they obstruct the animal’s eyes or mouth, interfering with its ability to see or eat.
Dr. Richard E. Shope, a researcher at The Rockefeller University, first identified the virus in the 1930s. His work was a crucial step in understanding the link between viruses and cancer, influencing later studies on conditions like the human papillomavirus (HPV). The virus has also been speculated to be the origin of the North American legend of the “jackalope,” a mythical rabbit with antelope horns.
CPW advises the public to maintain a safe distance and avoid touching or attempting to help these wild animals. The agency encourages residents to report sightings, which helps them monitor the spread of the virus within the state.
