Wild horses and mules. A mule is the offspring of a male donkey (jack) and a female horse (mare). Horses and donkeys are different species, with different numbers of chromosomes. Of the two first generation hybrids between these two species, a mule is easier to obtain than a hinny, which is the offspring of a female donkey (jenny) and a male horse (stallion). The wild horse is a species of the genus Equus, which includes as subspecies the modern domesticated horse (Equus ferus caballus) as well as the undomesticated konik heck. Free-roaming herds of feral mustang brumby horses. Animal environment herd high mountain mammal nature summer real mount mountainous montane higher elevation terrain treeless geography topography free wildlife altitude equine mare colt workhorse hack steppe spring outdoor barren hill hillside unspoiled unmanned nobody freedom mane purebred riding stud foal filly stallion liberty dehydrated plots waterless arid moorland independence latitude black brown flock wold veld stony slopes hoof galloping crowd gallop herd flock trot run runs running walk walking walks UHD 4K 3840X2160.