'Zombie squirrels' turning up in backyards and animal shelters across US

Wednesday, 20 August 2025 12:25

Though alarming to look at, the animals don't pose a threat to humans or most pets.

'Zombie squirrels' covered in gory sores have been turning up in backyards and at animal sanctuaries in the US, sparking concern online.

Though alarming to look at, the animals don't pose a threat to humans or most pets.

Photos of the rodents shared to social media platforms like Facebook, X and Reddit appear to show animals suffering from squirrel fibromatosis, also known as squirrelpox.

This squirrel suffering from squirrelpox was rescued by Halfway Home Wildlife Rehab in Michigan, USA, in July.

A common skin disease among grey squirrels in the US, squirrel fibromatosis is caused by leporipoxvirus.

The virus causes hairless growths or tumours which can turn into open sores.

These growths don't typically affect a squirrel's ability to survive unless, as in some rare cases, they spread to the animal's internal organs.

This can leave them weak and lethargic but death is rare.

Squirrel fibromatosis is spread through contact between healthy squirrels and the saliva or lesions of infected squirrels.

Common exposure sites include bird feeders set up by humans that multiple squirrels feed from.

Two different squirrels suffering from squirrelpox.

Fortunately for US residents who have spotted infected squirrels in their yards, the virus cannot be spread to humans or common pets like cats and dogs.

That being said, Shevenell Webb of Maine's Department of Inland Fisheries and Wildlife said residents should not interact with infected animals.

"I would not recommend trying to capture a squirrel that has the virus," Webb told the Bangor Daily News.

"It is naturally occurring and will run its course in time."

Cases of squirrel fibromatosis have been reported across the US for years and these new sightings fit with seasonal trends in rates of infection.

It's important to note that though squirrel fibromatosis is often referred to as squirrelpox in the US, it is an entirely different virus to UK squirrelpox, which can kill red squirrels.

Vadnais Heights, Minnesota. Eastern Cottontail rabbit." Sylvilagus floridanus" Rabbit with the papilloma virus (CRPV), or Shope papilloma virus,which is a type I virus under the Baltimore scheme, possessing a nonsegmented dsDNA genome. It infects rabbits, causing keratinous carcinomas, typically on or near the animals head. 6/18/2009

Earlier this months, reports emerged of a group of rabbits in Colorado that had grotesque, hornlike growths on their heads.

Dubbed "Frankenstein bunnies," "demon rabbits" and "zombie rabbits" online, they too were suffering from a relatively common virus.

They were infected with the mostly harmless Shope papillomavirus, which causes wart-like growths that typically clear up over time.

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