Mange in bears is a skin disease caused by microscopic mites that burrow into the skin, triggering intense itching, hair loss, and crusty lesions. It primarily affects American black bears and has been spreading across the eastern United States in recent years. While mild cases often resolve on their own, severe infestations can leave bears emaciated and disoriented, sometimes fatally.
What Causes Mange in Bears
Three species of mite have been linked to mange in black bears. The most common culprit, especially in states like Pennsylvania, is the same mite responsible for scabies in humans and mange in dogs. This parasite burrows into the outer layer of skin to lay eggs, and the bear’s immune response to the mites and their waste products drives most of the visible damage. A second mite species is specific to bears and causes a condition sometimes called “ursicoptic mange.” A third type lives in hair follicles and is generally less severe.
Genetic testing of mites collected from bears in Virginia, West Virginia, Maryland, and Pennsylvania has shown they are a canid variant, meaning the mites likely jumped to bears from wild canids like coyotes or foxes. This cross-species transmission helps explain why mange has been spreading through bear populations that historically had little exposure to it.
How Mange Looks and Progresses
In mild cases, you might notice a bear with patchy hair loss on its ears, face, or scattered spots along the body. The skin underneath may look dry or slightly irritated, but the bear otherwise appears healthy and behaves normally.
Moderate to severe cases are harder to miss. Hair loss becomes extensive, sometimes covering most of the body. The exposed skin turns thick, dry, and crusty, often covered with tan-colored scabs. Bears at this stage scratch and rub against trees constantly, which can cause open wounds vulnerable to bacterial infection.
In the most extreme cases, the disease reshapes the bear’s entire appearance. Severely affected bears lose so much fur they can be difficult to identify as bears at all. The constant energy drain from fighting the infestation and the inability to properly regulate body temperature depletes fat reserves. These bears lose significant muscle mass, become lethargic, and often wander into yards, roads, or open areas seemingly unaware of their surroundings. Bears that reach this stage are typically past the point of recovery.
Where Mange Is Spreading
Pennsylvania has been a hotspot for bear mange for over a decade and remains the state with the most documented cases. Virginia’s experience illustrates how quickly the disease can spread. From 2014 to 2017, reports were concentrated in just two northwestern mountain counties. By July 2024, mange had been confirmed in 24 Virginia counties, with the affected zone continuing to expand into 2026. Similar patterns have been documented in West Virginia and Maryland.
The geographic spread tracks with the canid origin of the mites. As coyote populations have expanded across the eastern United States, they’ve carried the parasites into new territory where bears encounter them through shared dens, resting sites, or scent-marking spots.
Can Most Bears Survive It?
The outlook depends heavily on timing and severity. A Pennsylvania study found that 74% of bears with mild to moderate mange overcame the infestation without any human intervention. Bears with healthy immune systems and adequate fat reserves can mount an effective response, eventually killing off the mites and regrowing their fur over a period of weeks to months.
The critical variable is season. A bear that develops mange in spring or summer has months of available food to maintain body condition while fighting the infestation. A bear heading into winter with active mange faces a dangerous combination: the energy cost of the immune response, impaired insulation from hair loss, and the normal caloric deficit of hibernation. Bears that enter dens already weakened by mange may not survive until spring.
How Wildlife Agencies Treat Mange
Wildlife biologists have been testing oral anti-parasitic medications on bears with mange. One approach uses a drug commonly prescribed for flea and tick prevention in dogs, delivered in a single oral dose. Research on black bear cubs showed the drug is metabolized faster in bears than in dogs, with a half-life of about five days compared to roughly two weeks in dogs. This means repeat dosing or higher concentrations may be needed for effective treatment in wild bears.
In practice, treating free-ranging bears is logistically difficult. It typically requires trapping the animal, which adds stress. Most state wildlife agencies reserve treatment for bears in moderate condition that have a realistic chance of recovery, rather than attempting to treat every affected individual. Bears in early stages are generally left alone, since most will recover naturally.
Can Mange Spread to People or Pets
The mites that cause mange in bears can temporarily transfer to humans and domestic animals through direct contact with an infected bear or contaminated surfaces. In humans, this causes short-lived itching and a rash, but the mites cannot complete their life cycle on human skin and die off within a few weeks without treatment. Dogs are more susceptible and can develop a full infestation if exposed, since the mites involved are genetically similar to those that cause sarcoptic mange in canids.
If you encounter a bear showing signs of mange, keep your distance and keep pets away from the area. Most state wildlife agencies have online reporting systems where you can log the sighting with a photo and location, which helps biologists track the spread of the disease and identify bears that may need intervention.