People can be taken aback by the sight of squirrels missing hair. Sightings of partially furred squirrels is not unusual with warmer temperatures experienced through the winter. Like many wildlife issues, the cause of hair loss in squirrels is not easy to answer and often results in more questions than answers. In most situations, hair loss does not impact populations of squirrels. However, individuals may be impacted during winter.
Most people assume, often incorrectly, that hair loss in squirrels is the result of mange, a disease caused by microscopic mites that burrow into the skin and are unseen by the naked eye. Hair loss attributed to the squirrel mange mite, Notoedres douglasi, has been reported in both fox and gray squirrels. Notoedric mange is different from sarcoptic mange. The latter, caused by the mite Sarcoptes scabiei, occurs primarily among red foxes and coyotes. Questions exist regarding the host specificity of mange mites. In light of new evidence, some pathologists now believe that sarcoptic mange mites are not as host-specific as previously thought. However, notoedric mange mites appear to be more host-specific, and don’t colonize non-hosts (like humans), although a few bites may occur. Transmission of notoedric mange to species other than squirrels has not been documented, including to canine and feline pets.
Symptoms of notoedric mange in squirrels includes loss of hair and dry, thickened and dark skin. Crust does not form on the skin in notoedric mange in squirrels like it does in sarcoptic mange in red fox. Mange is most commonly spread by direct animal to animal contact. Treatment of adult squirrels with mange is generally not recommended because reinfection from their nest is likely. An adult squirrel can survive mange if in otherwise good condition. While mange can be fatal to squirrels as a result of exposure during the winter, full recovery is often observed in squirrels.
For full article view Purdue Extension-FNR blog post, Question: I saw a squirrel with no fur on its neck, both backside and underneath. What is this?
Indiana Animal Disease Diagnostic Laboratory
Orphaned Wildlife, Got Nature? blog, Purdue Extension-Forestry and Natural Resources
Orphaned & Injured Animals, Indiana Department of Natural Resources (IDNR)