Rabbit Growths in Colorado Linked to Common Virus

DENVER — In Colorado, some rabbits recently spotted in Fort Collins are causing a stir, but it’s not as scary as it sounds. These rabbits, often described in somewhat unsettling terms, are simply infected with the Shope papillomavirus, a virus that isn’t particularly dangerous.

The cottontails in question have developed wart-like growths on their faces, resembling horns in some cases. This has led to a flurry of colorful nicknames, like “Frankenstein bunnies,” “demon rabbits,” and “zombie rabbis.” However, the virus itself isn’t new; it has a history that extends back almost a century, both in folklore and scientific study.

Interestingly, the mythical jackalope, a creature said to have rabbit-like features paired with antlers, is thought to have been influenced by this very virus. Additionally, research on this virus has helped scientists understand the link between certain viruses and cancer, including the human papillomavirus associated with cervical cancer.

This rabbit virus was named after Dr. Richard E. Shope, a professor from The Rockefeller University who identified it in the 1930s.

Recently, there’s been increased awareness of these rabbits in Fort Collins, about 65 miles north of Denver, as residents shared their sightings online.

Kara Van Hoose from Colorado Parks and Wildlife mentioned that they’ve received numerous inquiries about these bunnies. She noted that it’s fairly common to see infected rabbits, especially during summer when fleas and ticks, which spread the virus, are more active. The virus can be transmitted among rabbits, but it isn’t harmful to other animal species, including humans and pets.

According to Van Hoose, the growths might resemble warts but can take on a horn-like appearance if they grow longer. They generally do not pose a threat to the rabbits unless they appear near their eyes or mouths, which could affect their ability to eat. Fortunately, rabbits have immune systems capable of combating the virus, leading to the eventual disappearance of the growths.