Where Dinner Roams: The Role of Feral Horses as a Resource Subsidy for Wolves and Cougars in West-Central British...

Feral horses (Equus ferus caballus) have established large populations in west-central British Columbia (BC), Canada, where they overlap with native ungulates, including a declining woodland caribou (Rangifer tarandus caribou) herd. In addition, feral horses co-occur with large carnivore species including wolf (Canis lupus) and cougar (Puma concolor). Feral horses may act as a resource subsidy for predators, potentially altering predator-prey dynamics, yet empirical observations of predator interactions with feral horses are scarce in Canada. Between 2019 and 2025, we documented 21 instances of wolf predation or scavenging of feral horses, including one direct observation of wolves actively hunting feral horses. We also documented 58 instances of confirmed feral horse predation by GPS-collared cougars. To the best of our knowledge, these are the first published observations of wolves hunting feral horses, and the first records of cougar predation of feral horses in British Columbia. Our findings suggest that feral horses may increase food availability for these two large carnivore species, potentially facilitating elevated predation pressure on native ungulate populations via apparent competition. These novel interactions underscore the complex and far-reaching ecological consequences of feral species. Further, they highlight the importance of incorporating non-native prey subsidies into predator-prey management frameworks.