Colorado rabbits develop tentacle-like growths from virus

Rabbits in Fort Collins are showing unusual horn- or tentacle-like growths caused by rabbit papilloma virus. Officials say the virus is harmless to humans and pets.

Some rabbits in Fort Collins, Colorado, have been spotted with strange black, horn- or tentacle-like growths on their heads and faces. Colorado Parks and Wildlife (CPW) confirmed the cause: a virus known as Shope papilloma virus (SPV).

SPV is a naturally occurring papillomavirus that causes benign, wart-like tumors on rabbits, often appearing around the head and mouth. A Colorado Parks and Wildlife spokesperson, Kara Van Hoose, told the Coloradoan that residents alerted her last week to rabbits showing signs of rabbit papillomavirus.

Susan Mansfield told 9 News she saw a rabbit with black spines or “quills” around its mouth.

“It looks like it was black quills or black toothpicks sticking out all around his or her mouth,” Mansfield said. “I thought he would die off during the winter, but he didn’t. He came back a second year, and it grew." 

Despite their unusual appearance, these growths generally do not harm wild rabbits unless they obstruct the animals’ eyes or mouths, affecting their ability to see, eat, or drink, CPW said.

The virus is spread between rabbits by insect bites or direct contact, and can sometimes persist in local populations for years. Residents first noticed the growths in southeast Fort Collins, with some describing them as black quills or “toothpicks” protruding from the rabbits’ faces.

“While it looks alarming, the virus does not harm people or pets,” CPW said, urging the public to give infected rabbits space and avoid handling them.

The condition has been known since the 1930s and is relatively common among wild rabbits, but heightened sightings in Fort Collins have drawn attention due to the unusual appearance of the growths.

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