Feral Equids

Abstract

Feral horses (Equus ferus caballus) and burros (E. asinus) in North America, often referred to as free-roaming, free-ranging, or wild horses and burros, are introduced species that are currently increasing in arid and semi-arid rangelands. They differ from all other North American mammals by being the only feral species protected by federal law. These equids inhabit areas featuring rough topography, limited net primary productivity, and extreme weather conditions, and have potential to cause long-term ecosystem impacts. In this chapter, we review the historical and modern context of feral equids on North American rangelands including their evolutionary past and introduction to the continent, their relationships to the environment, and challenges associated with their management. The management of feral equids is perhaps more scrutinized than any other species because their legal status, body size, physiology, foraging patterns, and local abundance directly interacts and competes with rangeland resource quality, impacts native wildlife populations, and conflicts with the multiple-uses of the land that they inhabit.