Colorado residents are reporting sightings of rabbits with unusual black growths resembling horns or tentacles on their heads. Colorado Parks and Wildlife officials have identified the cause as shope papillomavirus (SPV), a rabbit-specific virus causing wart-like tumors. While SPV is not harmful to humans or other animals, officials advise avoiding contact with affected rabbits. The growths often disappear naturally, and the virus spreads through biting insects like fleas and ticks.

Prepared by Olivia Bennett and reviewed by editorial team.