Rabbits with ‘horns’ in Colorado are being called ‘Frankenstein bunnies.’ Here’s why
August 13, 2025
Some cottontail rabbits in Fort Collins, Colorado, have been drawing attention because they have wart-like growths on their faces that look like horns. The rabbits are infected with the relatively common Shope papillomavirus. The virus likely inspired the centuries-old jackalope myth. It also helped scientists learn about the connection between viruses and cancer, such as the human papillomavirus that causes cervical cancer. Experts say the virus cannot spread to other species. The growths don’t harm rabbits unless they grow on their eyes or mouths and interfere with eating. Rabbits’ immune systems are able to fight the virus. And once they do, the growths will disappear.