Karen C. Drayer Wildlife Health Center

Health and Disease

Since wildlife health is linked to human and domestic animal health, the team has been concerned with assessing the health of the mountain lions and bobcats that have been captured since the project began in 2001. All captured animals are given a health examination including blood, DNA and fecal sampling. We have become increasingly concerned about the levels of rodenticides and other toxins in captured felines.

A National Science Foundation-funded study is also tracking how viruses move between mountain lions, bobcats and domestic cats. Studying disease transmission not only gives us a better understanding of risk; it also gives us surrogate information about how these animals move across the landscape.

Disease exposure data from our study shows that cougars in southern California are exposed to a variety of infectious diseases, some at relatively high prevalence.  One paper has been accepted for publication in PlosOne in 2012 that details some of these findings. Other papers that have detailed other disease findings from the study (Franklin et al. 2007, Bevins et al. 2009) are listed in the references section of this report.

Cougar exposure to anticoagulant rodenticides remains a concern in our study area, as well as elsewhere in California. We have had samples from 23 southern California cougars analyzed for these substances and 100% of samples contained 1 or more of these compounds. In some cougars in our study area the levels were consistent with the amounts found in other cougars that have died as a consequence of the compounds’ direct toxic effects (Riley et al. 2007). The impact on cougar health of sublethal concentrations of these compounds is not well understood, but is of continuing concern and a subject of ongoing study into how these compounds are moving in the food chain. 

Our data in combination with data from other cougar study areas suggests that levels of rodenticides may be highest in those individuals that circulate closest to human habitations (Riley et al. 2010), however, more samples from GPS-collared cougars with known circulation patterns are needed to strengthen this statistical analysis. Our collaborative research can help provide important understanding of the unintended impacts of these substances.

samples are taken from a captured mountain lion