Viral Outbreak Turns Squirrels into 'Zombie' Creatures in US Backyards

People in Canada and the U.S. are seeing 'zombie' squirrels with tumors caused by the squirrel fibroma virus (SFV), a benign poxvirus that mainly affects squirrels and rabbits. The virus, spread by insects and contact, causes skin fibromas but generally doesn't harm the squirrel population or pose a threat to humans, and infected squirrels are safe to eat. The appearance of these infected squirrels has led to concerns, but the disease is typically self-limiting.