Group composition effects on aggressive interpack interactions of gray wolves in Yellowstone National Park

Gray wolves in Yellowstone National Park with a higher proportion of older members or adult males are more likely to win aggressive interpack interactions, even if numerically outmatched. This study analyzed 121 such conflicts over 16 years (1995–2010), revealing that relative pack size (RPS) generally favored the larger group but was moderated by composition. Packs with more experienced or dominant individuals had higher odds of victory, regardless of territory location. These findings suggest that while group living may offer advantages in territorial defense, certain individuals play a disproportionately critical role in interpack conflicts, offering insights into the adaptive benefits of wolf social structures.

Cassidy, K. A., MacNulty, D. R., Stahler, D. R., Smith, D. W., & Mech, L. D. (2015). Group composition effects on aggressive interpack interactions of gray wolves in Yellowstone National Park. Behavioral Ecology, 26(5), 1352–1360. https://doi.org/10.1093/beheco/arv081