The Virginia Bear Mange Study - Project Members and Overview

Impact of Sarcoptic Mange on Black Bear Population Size, Health, and Behavior

Virginia Bear Mange Study Project Members

• Virginia Department of Wildlife Resources

  • Carl Tugend, Black Bear Project Leader

  • Katie Martin, Deer-Bear-Turkey Biologist

  • John Tracey, DVM, State Wildlife Veterinarian

• Virginia Tech, Department of Fish & Wildlife Conservation

  • Wildlife Ecology Restoration Conservation Lab (WERC Lab)

    • Brett Jesmer, PhD, WERC Lab PI, Assistant Professor

    • Fang Chen, PhD Student

    • Brogan Holcombe, PhD Student, Geospatial & Enviromental Analysis Program

  • Wildlife Habitat & Population Analysis Lab (WHAPA Lab)

    • Marcella Kelly, PhD, WHAPA Lab PI, Professor

    • Madison Thurber, MS Student

    • Bella Sciarrino, MS Student

Project Background

Sarcoptic mange is a highly contagious mammalian skin disease caused by an infestation of mites (Sarcoptes scabiei) that threatens the persistence of abundant black bear populations, their ecological roles, and their recreational and cultural importance. In Virginia, sarcoptic mange recently spread rapidly along the western mountains, yet neither the short nor long-term demographic, health, or behavioral consequences of sarcoptic mange on black bear populations are known. 

To study the impact on the population, we will be estimating American black bear densities in Virginia’s Allegheny and Blue Ridge Mountains through spatially explicit, mark-recapture analysis using DNA from hair samples collected at barbed-wire corral traps (i.e., hair snares). We plan to assess the impact of sarcoptic mange on bear population density by comparing areas with high mange detection in areas without known mange detection. We will also be monitoring the hair snares in mange-inflicted areas with trail cameras to assess the severity of mange at each of these sites. ​

To better understand the impact of mange, we are equipping adult female black bears with GPS tracking collars. We are also equipping all male, juvenile, and subadult bears with VHF ear tag transmitters. These devices will allow us to monitor mortality and reproduction for 2-3 years. To understand the potential impact of mange on bear reproduction, we will conduct den checks of GPS-collared female bears in February-March, which will allow us to count cubs and conduct health checks on both mother and cubs. Armed with mortality and reproductive data in hand, we will quantify how mange infestations are impacting both the short and long-term population size of black bears.

Mange is also thought to alter bear behavior by increasing the need for food to support the immune response mounted to combat the mite infestation. Because mange infestations cause bears to lose considerable amounts of hair, we also expect mange-affected bears to shift their habitat use towards those offering cooling temperatures in summer and warmer temperatures in winter, and potentially towards more human-occupied habitats that offer, high calorie foods, such as bird feeders, trash cans, and agricultural fields. To determine how mange influences bear activity patterns, habitat selection, and interactions with humans, we will statistically analyze the GPS tracking data. By doing so, we hope to understand the relative roles the immune and behavioral responses play in the declines in body condition often associated with mange infestations and, ultimately, how declines in body condition lead to declines in reproduction and survival. 

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