Dogs in shelters often experience social isolation and chronic stress, reflected in elevated levels of the stress hormone cortisol. To explore how brief fostering opportunities might ease these effects, Lisa M. Gunter and colleagues conducted a large-scale study published in PeerJ examining the physiological and behavioral impacts of one- and two-night foster stays on shelter dogs.
The research involved 207 dogs from five animal shelters across the United States, including both open- and limited-admission facilities. Dogs’ urinary cortisol:creatinine ratios were analyzed before, during, and after fostering to measure stress. Each dog also wore a non-invasive activity monitor tracking heart rate and rest patterns in both the shelter and foster homes.
Results showed that cortisol levels dropped significantly during fostering, indicating that even brief removal from the kennel environment provided measurable stress relief. Dogs also exhibited longer, uninterrupted rest periods while in foster homes—another indicator of improved welfare. However, once the dogs returned to the shelter, their cortisol levels returned to baseline, suggesting that the benefits of fostering are temporary unless kennel stressors are also addressed.
Interestingly, the extent of cortisol reduction varied between shelters, implying that environmental factors—such as noise, social structure, or staff interaction—play a critical role in canine welfare. The study also found that older, heavier dogs and those with higher resting pulse rates tended to have higher cortisol levels overall.
The findings emphasize that short-term fostering can provide valuable psychological reprieve for dogs awaiting adoption, while underscoring the importance of improving shelter conditions to ensure sustained welfare. By combining environmental enrichment, human interaction, and structured foster programs, shelters can significantly enhance the well-being of dogs in their care.
Source: Gunter, L. M., Feuerbacher, E. N., Gilchrist, R. J., & Wynne, C. (2019). Evaluating the effects of a temporary fostering program on shelter dog welfare. PeerJ, 7. Published March 27, 2019.
