For a very long time, wolves – those long-legged, rawboned, lolling-tongue predators of forest, shrubland, steppe, and desert across the Northern Hemisphere – have coursed their way after horses: also long-legged, also rawboned, also of strong heart and lungs and high endurance. It’s a deep-rooted predator/prey relationship, but one that these days isn’t all that commonly observed.
Yet here’s a glimpse of that age-old interplay, coming to us from the eastern foothills of the Rocky Mountains in Alberta, Canada, and via a non-profit dedicated to the welfare of that area’s feral horses:
The footage, captured last year but only shared this month, shows a band of 'wildies' rebuffing wolves apparently intent on a foal.
Although North America is where, paleontological evidence suggests, equids evolved – and a place where wolves long shadowed them – they became extinct on the continent something like 8,000 to 11,000 years ago while persisting in Eurasia and Africa. Centuries ago, horses returned to the New World via European colonisers, and, one way or another, many escaped the confines of domesticated life and became free-ranging beasts on ancestral turf.
The east slope of the Alberta Rockies is one of several places in Canada host to feral horses (which south of the border in the US are commonly called mustangs – “wildie” and “mustang” being North American analogues to, for example, the “brumbie” of Australia). Previous research has documented that wolves in this region do sometimes take feral horses, alongside such wild ungulates as white-tailed and mule deer, elk, and moose. A 2022 study, meanwhile, showed that free-range horses on British Columbia’s Chilcotin Plateau form a significant food source for grey wolves; some of that horse-flesh, the authors note, surely comes through scavenging, but they also propose that wolf predation on, for example, foals and winter-weakened adult horses is likely. Another of Canada’s free-roaming horse herds, which calls west-central Saskatchewan’s Bronson Forest home, has also experienced wolf predation.
Although grey wolves overlap with both mustangs and domestic horses in other parts of North America, wolf predation on equids is better recorded from Eurasia. Wolves in Central Asia are known to prey on reintroduced Prezwalski’s horses (tahkis) and two subspecies of the Asiatic wild ass called the onager – the Mongolian and the Turkmenistan kulan – as well as domestic horses. Horses can also be significant parts of wolf diet in Southern Europe, including such comparatively rare, ancient, small breeds as the Petro horse of southern Italy, the Pottok of the Pyrenees, and various “mountain ponies” of the Iberian Peninsula, such as the Galician horse of northwestern Spain and the garrano of northwestern Portugal.
Such horses are often best described as semi-domesticated; traditional husbandry of Galicians and garranos sees them free-ranging most of their lives, only subjected to occasional roundups, and thus – unlike livestock brought in at night – out and about in wolf country most of the time. Research suggests that, where they overlap, mountain ponies can constitute the number-one prey of the Iberian wolf, the region’s subspecies of grey wolf.
Direct encounters between wolves and horses, such as the above video shows, have not been recorded terribly much in the scientific literature. But when they have, they often document a similarly aggressive defence as shown by the Alberta wildie stallion.
A 2022 paper, for example, summarised some predatory interactions between Iberian wolves and free-ranging ponies in northwestern Spain and Portugal via direct observations and interviews with shepherds. Mountain ponies alerted to the presence of wolves typically bunched together vigilantly. Approaching wolves prompted horses either to flee or to stand their group and “fend off wolves with rushes.” In one event relayed to the authors by a shepherd, a wolf chased ponies fleeing in a roughly linear, single-file line – a similar arrangement as has been reported in Alberta, the study noted, in which a large wildie harem noticing a nearby wolf departed “calmly” in a line “with the stallion protecting the rear.”
Iberian wolves do sometimes prey on full-grown horses – as in winter, when mountain ponies may be in poorer condition – but most of the accounts reported in this study saw foals the primary target. Both the stallion and mares in a given band would actively defend these youngsters: kicking at wolves with fore- and hind-legs, and also trying to bite.
Similar behaviour was reported from Mongolia’s Gobi National Park in a 1994 paper focused on Mongolian kulan, of which wolves are the primary predator. Researchers observed three wolves, one a lactating female, attacking a kulan foal and, in turn, being counter-attacked by a stallion and mare together – the former “mainly using open-mouth bite attempts and foreleg kicks, [the] mare mainly hindleg kicks, staying close to the foal.” A wolf ultimately killed the foal, but the feeding pack continued to endure occasional aggression from the kulan stallion and mare.
Equids follow two main social/breeding structures. One, seen in Grevy’s zebras and certain wild asses, is the territorial system, in which a male defends a territory (hopefully) situated auspiciously in relation to a resource – a waterhole, say, or good forage – which attracts females. The other system – which, as Richard D. Estes noted in The Behaviour Guide to African Mammals, is much rarer in the mammalian realm – is the harem model, wherein a single stallion manages a small coterie of mares, and harem-less males may form bachelor gangs. This is the lifestyle usually followed by plains and mountain zebras, Mongolian kulan, tahkis, and feral horses. Bonds between harem members are strong, and the band stallion will fiercely defend mares and foals not only from predators, but also rival males.
One hypothesis for how these two modes developed in equids is because of differing resource-distribution patterns. Deserts and other arid drylands, where water and pasture may be scattered widely in discrete areas across the landscape, the theory goes, might encourage the development of a territorial system in equids. Where resources are more evenly spread, a harem-style mode – as Estes notes, one in which stallions basically “substitute movable for fixed property” – could be supported.
But predation pressure might have played just as significant a role in the development of harems among equids. Group defence – mares ranking around vulnerable foals, the stallion engaging predators and, if the band is actively fleeing, putting up an aggressive rear guard – is “perhaps the most important advantage of the harem over the territorial system,” Estes writes.
The purpose of the 1994 study on Mongolian kulan referenced above was to try to ascertain whether this onager subspecies followed the territorial lifestyle typical of most other wild asses or, alternatively, the harem one.
In showing strong evidence for the latter in the wolf-harried Mongolian kulan, the authors proposed that perhaps an alternative or at least contributing factor to the harem/territoriality dichotomy in the horse family is the kind of predation equids are exposed to. While most territorial equids primarily contend with smaller or solitary hunters such as jackals (and the small Indian wolf, in the case of the Indian wild ass or onager), the harem-living species deal with large, “pack”-hunting beasts: grey wolves, African lions and spotted hyenas, to name a few formidable examples. Perhaps the communal defence afforded by a tight-knit breeding team of one stallion and several mares in face of such cooperative carnivores helped give rise to the wild-horse harem, even if the layout of resources was also a formative variable.
“The experience and perseverance of mares as well as the stamina in protective behaviour of stallions seem to be important functions influencing the outcome of [wolf] attacks,” wrote the authors of the 2022 paper focused on wolf/pony interactions in Northwest Iberia. “The level of cohesion in a band, which reinforces group defense, may also be important, including the ability of stallions to keep mares together, preventing them from becoming separated from the band and thus more vulnerable.” The authors suggest further “that more experienced mares may reduce predation by increasing vigilance and avoiding areas where the risk of being ambushed by wolves is higher.”
From Rocky Mountain forests to the rolling pastures of the Iberian Peninsula, free-roaming horses and wolves continue to enact their time-tested prey-predator dance. And in the former setting, those Alberta wildies aren’t only dodging wolves: Last year, we shared some HAWS clips showing grizzly bears tailing horses.
Top header image: Stefan Rusche/Flickr
Predator vs Prey
Animal Behaviour
Predator vs Prey
