Human population growth in the San Francisco Bay Area has degraded wildlife habitat and has led to the loss of mountain lions from Marin County. Now human actions also threaten the bobcat population: bobcats in modified habitats are more likely to be genetically isolated, exposed to pathogens from pets and in contact with human-released environmental toxins. We will non-invasively collect samples from bobcats in Marin to determine the genetic health of this population.