Validating a New Indicator of Welfare for Grizzly Bears
The field of animal welfare is always advancing as we discover and validate new means of assessing individual well-being. At the Detroit Zoological Society, we are particularly interested in establishing comprehensive physiological measures. Measures of oxidative stress may allow for exploration of both positive and negative life experiences. We used fecal samples to examine oxidative stress through concentrations of 8-hydroxy-2’-deoxyguanosine (8-OHdG), a byproduct of DNA damage, in three adult male grizzly bears (Ursus arctos horribilis). We hypothesized that adrenal activity would contribute to oxidative stress and subsequent DNA damage while the bears were temporarily housed in a smaller habitat during the renovation and expansion of their primary habitat. These habitat improvements allowed for preliminary validation of 8-OHdG concentrations against another validated physiological measure (fecal glucocorticoid metabolites or FGMs) and behavioral data. As expected, we found that concentrations of 8-OHdG increased significantly as FGM concentrations increased. The relationship between 8-OHdG and behavior was more complicated. We initially predicted that 8-OHdG would be lower when individuals demonstrated higher rates of positive social interactions, but this relationship was only confirmed in one of the three bears. This study lends preliminary support for 8-OHdG as a non-invasive animal welfare measure, but we look forward to continued validation efforts.