New study looks as sociality and disease in bighorn sheep herds

Bighorn sheep may be more susceptible to disease based upon how social they are. A new study, “Bighorn sheep associations: understanding tradeoffs of sociality and implications for disease transmission,” looked at the ways in disease transmission and survival rates are related to social behavior, according to Phys.org.

Published in PeerJ Life & Environment, the study was led by Marie Tosa, now with Oregon State University, and conducted on behalf of the U.S. Geological Survey and National Park Service. Researchers concentrated efforts on “understanding the factors influencing direct contact rates” for bighorn sheep that live around the Waterton-Glacier International Peace Park. These factors included relatedness and age as well as terrain and season. The study took place between 2002 and 2012, using GPS collars to track movements and interactions.

Researchers discovered that more direct contact was made between same-sex groups rather than male-female and bighorn herds with “overlapping summer home ranges” had higher direct contact rates with higher occurrences during the winter-spring season. There was also increased sociality in areas with more predation potential, resulting in the possibility that bighorn sheep use contact as a means of survival. Terrain also played a factor in level of contact among bighorn sheep with “ruggedness, distance to escape terrain, and canopy cover” recognized as “key drivers” of contact between different bighorn sheep herds. 

Tosa noted “the importance of contact analysis in understanding the fitness tradeoffs of sociality and the potential for disease transmission among bighorn sheep populations,” adding that there is a “delicate balance” between “social behavior and disease dynamics in challenging environments.”

This research is highly relevant to continued study on the necessity of conservation efforts for “safeguarding wildlife populations and mitigating disease risks,” according to Phys.org.