Recently, residents in Colorado have been startled by the sight of wild rabbits with black, horn-like or tentacle-like growths protruding from their heads and faces. These bizarre appearances have sparked rumors and fear, with some dubbing them “Frankenstein rabbits” or “zombie bunnies.”

However, wildlife experts have confirmed that these growths are caused by a known and studied viral infection called the Shope papilloma virus (SPV), also known as cottontail rabbit papillomavirus (CRPV).

Frankenstein Rabbits in Colorado
Frankenstein Rabbits in Colorado


What is the Shope Papilloma Virus?

Shope papilloma virus is a DNA virus that specifically infects wild cottontail rabbits. It was first discovered in the 1930s by Dr. Richard E. Shope, who found that infected rabbits developed wart-like tumors (papillomas) on their skin, particularly around the face, head, and neck.

These papillomas can become elongated and keratinized, giving the appearance of horns, spikes, or black tentacles.


How Does the Virus Spread?

The virus spreads mainly through:

Biting insects such as mosquitoes, fleas, and ticks.

Direct contact between infected and healthy rabbits.

Importantly, Shope papilloma virus is not contagious to humans, pets, or other wildlife. It is strictly a rabbit-to-rabbit infection.


Are the Rabbits in Pain?

In most cases:

The papillomas are benign and do not cause major harm.

Rabbits can live for years with the growths.

Problems arise if the growths block vision or mouth movement, making it difficult for the rabbit to eat or avoid predators.

In severe cases, rabbits may starve or become more vulnerable to accidents.


Why the Sudden Sightings in Colorado?

While SPV has been most commonly reported in Midwestern states, sightings in Colorado have increased recently, likely due to:

Warm weather boosting insect activity.

Better public awareness and social media sharing.

Natural spread of the virus among local rabbit populations.


A Historic Discovery with Scientific Impact

The Shope papilloma virus was groundbreaking in medical research. In the 1930s, studies of SPV helped scientists understand virus-induced cancers, paving the way for cancer virology as a research field.


Public Safety and Wildlife Advice

Do not touch or handle affected wild rabbits.

Keep pets away from wildlife to prevent stress or injury.

If you spot infected rabbits in urban areas, report them to local wildlife authorities so they can monitor the spread.


Key Facts at a Glance

Cause: Shope papilloma virus (cottontail rabbit papillomavirus).

Appearance: Black horn-like or tentacle-like growths on face and head.

Spread: Biting insects and rabbit-to-rabbit contact.

Risk to Humans/Pets: None.

Impact: Usually harmless unless growths affect feeding or vision.

First Discovered: 1930s by Dr. Richard Shope.


FAQ's

Q1: Are the “Frankenstein rabbits” dangerous to people?
No. The Shope papilloma virus does not infect humans, dogs, cats, or other animals.

Q2: Can the virus be cured in rabbits?
In wild rabbits, there is no treatment. The condition usually runs its course unless complications occur.

Q3: Is this the same as rabbit hemorrhagic disease?
No. Rabbit hemorrhagic disease is a different and often deadly virus. SPV is generally non-lethal.

Q4: Why do the growths look like horns or spikes?
The papillomas can harden and grow into keratinized structures, resembling horns or quills.

Q5: Should I call animal control if I see one?
If the rabbit appears injured, starving, or is in a hazardous area, contact local wildlife services.