Experts issue alert after ‘zombie squirrels’ spark concern across the US

Most people only pay squirrels a passing glance in a park or backyard, but a recent batch of sightings has left many feeling unsettled.

Photos circulating online show some squirrels with pronounced lumps and wart-like bumps on their bodies, prompting speculation over whether the animals are injured, sick, or affected by something more unusual.

In one Reddit post, a user shared images of a squirrel with a large growth on its face, saying they first assumed it was eating, before realising “the mass was on its face”. The poster wondered if it could be fibromatosis or another viral issue, though the exact cause wasn’t immediately clear.

As similar images began appearing in Maine, wildlife experts stressed the disturbing look doesn’t point to a brand-new outbreak. Reported by Bangor Daily News, specialists later urged the public to keep their distance after “zombie” squirrels with visible wart-like growths were spotted in parts of the US, warning people not to approach or try to handle them.

One possible explanation is squirrel pox, a naturally occurring virus that can lead to hair loss, sores, and raised lesions, often around the eyes, mouth, and feet. While the squirrels’ appearance has led some to compare them to something out of a horror movie, specialists say many cases resolve without human involvement.

Shevenell Webb, a wildlife biologist and furbearer specialist with the Maine Department of Inland Fisheries and Wildlife, has previously cautioned against attempting to rescue infected squirrels. Webb said: “I would not recommend trying to capture a squirrel that has the virus…It is naturally occurring and will run its course in time.”

Experts believe transmission is more likely when squirrels congregate closely, especially around bird feeders where saliva can be left on shared surfaces. Webb explained: “It’s like when you get a large concentration of people. If someone is sick and it’s something that spreads easily, others are going to catch it.”

Even when the growths look extreme, many squirrels recover, and the virus isn’t known to spread to humans or household pets. Wildlife officials note that, in uncommon cases, the disease can progress internally and become fatal, but the recommended response is to avoid interfering and let nature take its course.

Wildlife rehabilitators have also highlighted that parasites can sometimes create similar-looking swellings. Specialists at Evelyn’s Wildlife Refuge have pointed to botflies and noted that the larva “tunnels through the flesh”, which can leave prominent bulges. In its warning, the centre added: “Only skilled rehabbers or vets should attempt to extract bots.” In any case, rescue groups emphasise that treatment should only be done by trained professionals.

It’s not the first time wildlife illnesses have caused alarming appearances in the US. Not long ago, rabbits appeared to have “tentacles” emerging from their faces due to the cottontail papilloma virus.

Even so, the unsettling squirrel photos have stuck with many viewers. When the situation first began gaining attention, one user on X (formerly Twitter) captured the mood for a lot of people by posting: “Zombie Squirrels?! Seriously?! FFS!!”