Denver (AP) – A group of Colorado rabbits with grotesque growths and similar to a horn may seem directly outside a low -budget horror film, but scientists say that there is no reason to be frightened – fur creatures simply have a relatively common virus.
Cottontails recently spotted in Fort Collins are infected with the most harmless shop papillomavirus, which causes wart -shaped growth which exceed their faces as metastasing horns.
This August 2025 photo provided by the University of Kansas Biodiversity Institute shows a rabbit sample with the Shoped Papillom virus at the University of Kansas Biodiversity Institute. (Graciousness of the Institute of Biodiversity of the University of Kansas via AP)
The viral photos inspired a handkerchief of unflattering nicknames, notably “Frankenstein Bunnies”, “Demon Rabbits” and “Zombie Rabbits”. But their affliction is not new, the virus inspiring ancient folklore and fueling scientific research almost 100 years ago.
The virus probably influenced the myth of secular jackalope in North America, which spoke of a rabbit with woods or horns, among other animal variations. Rabbit disease has also contributed to the knowledge of scientists on the link between viruses and cancer, such as human papillomavirus which causes cervical cancer.
The virus in rabbits was appointed according to Dr. Richard E Shop, professor at Rockefeller University who discovered Cottontails disease in the 1930s.
News on rabbit observations in Fort Collins, at 65 miles (105 kilometers) north of Denver, began to draw attention after residents began to spot them in the city and publish photos.
A rabbit infected with the virus of the shop papilloma, which causes growth of the wart type which can resemble horns, is visible to Fort Collins, in Colorado, in August 2025. (Gracious Amanda Gilbert via AP)
Kara Van Hoose, spokesperson for Colorado Parks and Wildlife, told the Associated Press on Wednesday that the agency had received calls on rabbits seen in Fort Collins.
But she said that it was not uncommon to see infected rabbits, especially in summer, when the chips and ticks that distribute the virus are the most active. The virus can spread from rabbit to rabbit, but not to other species, including humans and pets, she said.
Sulls look like warts but can look like horns if they grow longer, said Van Hoose. Croissance hurt rabbits unless they develop in their eyes or mouths and interfere with food. Rabbit’s immune systems are able to fight the virus and, once they do, growth will disappear, she said.
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Finley reported Norfolk, Virginia.
