Frankenstein” Rabbits in Colorado: What You Need to Know

Residents of Fort Collins, Colorado, have been startled by unusual and unsettling sightings: wild cottontail rabbits with tentacle-like, horn-shaped growths sprouting from their heads and faces. Photos have quickly circulated online, earning the nickname “Frankenstein rabbits.” While the appearance is alarming, wildlife experts say the phenomenon has a clear biological explanation.

The Culprit: Cottontail Rabbit Papilloma Virus (CRPV)

The bizarre growths are caused by Cottontail Rabbit Papilloma Virus (CRPV), a virus that infects wild rabbits. Once inside a rabbit’s body, CRPV triggers the formation of hard, tumor-like outgrowths—often around the head, mouth, and eyes.

These growths aren’t just cosmetic:

• They can block vision, leaving rabbits vulnerable to predators.
• They may obstruct hearing, making it harder to detect danger.
• They sometimes interfere with eating, which can lead to malnutrition or starvation.

How the Virus Spreads

CRPV passes from rabbit to rabbit in two main ways:

1. Insect vectors – Mosquitoes and ticks can carry the virus from one host to another.
2. Direct contact – Rabbits fighting, grooming, or breeding can spread it among themselves.

The virus appears to be limited to rabbit species—meaning it does not cross into humans or other animals.

Is It Dangerous to Humans or Pets?

Wildlife disease specialists emphasize that CRPV cannot infect humans, cats, or dogs. However, there’s still a risk in handling an infected rabbit:

• Injured rabbits can bite or scratch.
• You could inadvertently spread the virus to other rabbits, especially if you have pet bunnies.

Rule of thumb: If you see a sick or strangely appearing wild rabbit, do not touch it.

What You Should Do if You Spot One

If you encounter a rabbit with CRPV symptoms:

• Keep your distance and ensure pets are restrained.
• Report the sighting to your local wildlife authority so they can track the outbreak.
• If you own pet rabbits, protect them from mosquitoes and ticks using approved repellents and housing.

Nature’s Oddities: Fascinating but Best Observed Safely

While the sight of a horned rabbit might seem like something from a horror story—or a myth about the “jackalope”—this is a real, naturally occurring wildlife disease. It’s a stark reminder that nature is both wondrous and sometimes unsettling.

By respecting boundaries, reporting cases, and protecting domestic animals, residents can help manage the spread of CRPV while avoiding unnecessary risks.

Bottom line:

Those “Frankenstein” rabbits may look like creatures from another world, but they’re victims of a virus that has long existed in nature. Admire them from afar, alert the experts, and let wildlife handle wildlife.