Abstract The Mexican gray wolf (hereafter Mexican wolf; Canis lupus baileyi ) is a federally listed endangered subspecies whose population is recovering in Arizona and New Mexico, USA, and parts of northern Mexico. Predatory behavior of Mexican wolves has become increasingly studied in recent years following their initial reintroduction to the wild beginning in 1998, with wolves in the United States preying predominantly on elk ( Cervus canadensis ). Using global positioning system (GPS) collar data, we monitored 36 Mexican wolves from 24 packs to investigate GPS cluster locations formed by wolves to locate prey remains and identify prey composition from 2019 to 2023. During our 4‐year study, we documented 2 cases of Mexican wolves killing and consuming free‐roaming horses ( Equus caballus ) in New Mexico and Arizona. Although wolf predation on feral and native wild horses has been reported for many parts of Europe, Asia, and Canada, predation of feral horses by wolves has not been reported in the United States. As wolf populations continue to grow throughout North America, this behavior may become increasingly common in areas where the distributions of wolves and feral horses overlap. Feral horses may provide a novel food source for wolves, particularly in regions where native prey populations are more limited. We hope that these findings can help highlight the gap in knowledge that exists when considering wolf ecology, restructured food webs, and the potential role feral horses could play as wolf populations increase in the American West.
Martinez et al. (Thu,) studied this question.