DENVER, Colo. — A bizarre phenomenon is capturing attention in Fort Collins, where rabbits afflicted with unusual hornlike growths have spooked residents. Contrary to the alarming visuals reminiscent of a horror movie, experts assure the public that the cottontails are simply dealing with a common viral infection.

The growths seen on these rabbits are caused by Shope papillomavirus, a largely benign virus that leads to wart-like protrusions. These unusual formations can extend from the animals’ faces, creating an eerie appearance that has spurred a flurry of unflattering nicknames, such as “Frankenstein bunnies” and “zombie rabbits.”

This virus has long been a subject of interest not only in folklore but also in scientific research. It likely inspired the legendary jackalope, a mythical creature featuring the body of a rabbit and antler-like protrusions. The implications of this virus extend beyond the bizarre; it has played a significant role in advancing our understanding of the relationship between viruses and cancer, paralleling research conducted on human papillomavirus, which is linked to cervical cancer.

Identified by Dr. Richard E. Shope in the 1930s, the virus owes its name to the renowned professor from The Rockefeller University who first observed its effects in wild cottontails. Since then, the Shope papillomavirus has been a focal point of research and folklore.

Recent sightings in Fort Collins, located roughly 65 miles north of Denver, have sparked curiosity and concern among residents. Photos of the afflicted rabbits circulating on social media fueled public interest and prompted inquiries to local wildlife officials.

Kara Van Hoose, a spokesperson for Colorado Parks and Wildlife, confirmed that the agency has received multiple reports regarding these rabbits. She noted that such infections are not unusual, especially during summer months when the fleas and ticks that transmit the virus are most active. Importantly, the virus spreads only among rabbits and poses no threat to humans or other animals.

The growths can resemble warts but can take on a more horn-like appearance if they lengthen, according to Van Hoose. While the growths are generally harmless, they can cause issues if positioned around the eyes or mouth, potentially affecting the rabbits’ ability to eat. However, rabbits typically have robust immune systems capable of combating the virus, allowing the growths to recede over time.

Van Hoose emphasized the need for understanding and compassion toward these rabbits. With their immune systems often managing the infection, the growths typically resolve without severe impact on the animals’ health. This occurrence in Fort Collins is a vivid reminder of the intricate ties between wildlife, health, and folklore, blending natural phenomena with cultural storytelling.