Reported sightings in the Chicago suburbs of sick-looking canines could be so-called zombie coyotes.
The wild animals are believed to be suffering from a contagious disease called sarcoptic mange, and the ghoulish nickname comes from the condition's effects on behavior and appearance, including fur loss and skin problems.
Sightings have popped up in northwest and southwest portions of Cook County, said Chris Anchor, senior wildlife biologist for the Forest Preserves of Cook County, who studies coyotes as part of the Urban Coyote Research program and whose team has come across ailing coyotes.
And the Hanover Park Police Department issued an alert last week, advising people and pets to stay away from the animals.
The department said on its Facebook page that it received several reports from citizens "concerned about what appear to be malnourished or neglected stray dogs. These are NOT lost pets, but are in fact coyotes."
The alert reported that sarcoptic mange is on the rise in urban coyote populations, and the condition is what can eventually have the animals "looking like some sort of 'zombie' dog."
Despite the mange's macabre effects, the condition is rarely life-threatening, including in unusual cases where it spreads to household pets through direct contact with a coyote, Anchor said. Pets can be treated with medication from a veterinarian and typically make a full recovery, he said.
One risk for infected wildlife is that the hair loss can prevent animals from generating enough body heat, Anchor said. But even when coyotes are infected in colder months, many are "smart enough" to seek shelter in places like backyard compost heaps or find other ways to stay warm, he said.