Recent footage out of Alberta, Canada along the eastern foothill flanks of the Rocky Mountains shows a high-drama encounter between two symbols of the North American wilderness: wild (aka feral) horses – widely known in the American West as mustangs and, in Alberta, sometimes as 'wildies' – and that formidable New World subspecies of the brown bear, the grizzly.

The trail-camera footage, posted to the Facebook page of the non-profit Help Alberta Wildies Society (HAWS), shows a band of feral horses in full flight, with a grizzly bear hot on their heels (and another grizzly tagging along at a mosey well behind): 

A Facebook update by HAWS on June 27th revealed that the grizzly’s predation attempt was unsuccessful, as all horses had been accounted for.

The capture was something of a repeat from last year, when HAWS shared striking trail-cam video (from the afternoon of May 26, 2022, to be exact) of a grizzly motoring along after a panicked horse band containing foals:

This time of year, grizzlies across much of their diminished range are including (or attempting to include, anyhow) actively hunted ungulate meat in their decidedly non-picky omnivorous diets. From elk and moose calves to, yes, mustang foals, the young of hoofed mammals are most vulnerable to bear predation in spring and early summer, before they’ve attained the speed and endurance to outpace a charging bruin.

The prime window for this predation tends to be short, though as summer ripens grizzlies can happily shift over to flourishing plant-based foods – not least berries – and perhaps look forward to knocking off the odd rut-weakened elk come fall.

While the Albertan mustangs in these videos were understandably trying to rapidly put some distance between themselves and those huffing grizzly bears, it must be emphasized that feral horses aren’t exactly easy prey. One only needs to review how challenging zebras are as quarry for Africa’s superlative roster of large carnivores (and supersized reptiles) – or maybe watch a couple of mustang stallions square off – to gain respect for equine tenacity.

In many parts of their scattered global range, furthermore, feral horses don’t face major predation pressure for the simple fact that significant natural predators such as wolves and big cats have been extirpated. Some studies, though, have suggested herds in such landscapes may still respond to playback of vanished-carnivore vocalizations such as lion roars, wolf howls, and leopard growls.

Where they do cross paths, as we’ve seen, bears – not only grizzlies, but also potentially American black bears – may pose a threat to young or weakened mustangs. Gray wolves, meanwhile, still course after free-ranging horses in places (from Galicia, Spain to interior British Columbia), spotted hyenas trail feral Namib Desert horses, and dingoes may try for the foals of Australian brumbies.

And at least in parts of western North America, a critter much more widespread there today than the grizzly bear – the mountain lion – has shown itself a capable mustang-hunter.

A 2021 study identified cougars in the western Great Basin of Nevada, USA as notable predators of feral horses. That research found that 60% of all kills by GPS-collared cougars tracked from 2009 to 2012 were mustangs. While mule deer serve as the most important prey for mountain lions across much of western North America, this work suggests some cougars there have become specialist wild-horse hunters.

Warning: Graphic content. The mountain lion has shown itself a capable mustang-hunter.

Both male and female cougars stalked horses, but males most heavily targeted them during the spring and early-summer foaling season, then mainly switched over to mule deer. Some female cougars, by contrast, preyed on mustangs year-round.

Full-grown mountain lions weigh on the order of 36 to 91 kilograms (80 to 250 pounds), well shy of a mature mustang. As with their ability to prey on bull elk and occasionally moose, the fact that these predominantly solitary cats can wrestle down a feral horse is certainly testament to their brawniness – though this sort of predation can be a hard-knocks affair.

A feral horse “is a risky prey item,” researcher Jon Beckmann, a co-author on the 2021 Nevada study, told The Wildlife Society. “We’ve seen over the years some cougars that are pretty beat up – you can tell the horse eaters. It’s a rough life trying to take down 800 – 1,000-pound [363 – 454 kg] animals.”

Black bears are expanding their range in the semi-arid mountain ranges and sagebrush steppes of the Great Basin. While they haven’t yet demonstrated themselves to be significant mustang predators here themselves, the bears, as enthusiastic kleptoparasites, will drive cougars off horse kills. If that kleptoparasitism increases, biologists have speculated that Great Basin cougars might shift away from hunting mustangs to favouring smaller, less-dangerous deer as prey, given it’s a major energetic blow to tackle a hazardous-but-big-payoff horse for dinner, only to lose it to a pirating bear.

As research into cougars hunting free-roaming Mojave Desert burros has suggested, predation on feral North American horses and donkeys by pumas, bears, and wolves resurrects bygone ecologies when such predators – not to mention extinct counterparts such as American lions – dined on homegrown horseflesh. Equids, after all, are thought to have evolved in North America, but went the way of many other megafauna there – i.e., they went extinct – around the close of the Pleistocene.

First reported predation of feral donkeys by cougars, captured by trail camera. Image © Lundgren, et al.

Modern horses returned to the continent in the 16th century with Spanish colonizers, and spread rapidly through intentional trade and breeding as well as feralization thereafter, with a slew of Native American cultures adopting the animals (and, in many cases, becoming world-class equestrians in short order). Escapees and intentionally released animals have helped maintain free-ranging feral horse herds on the North American landscape ever since, from the barrier islands of the Atlantic coast to the “sagebrush sea” of the Intermountain West and the Eastern Slope of the Canadian Rockies, where those grizzly-dodging wildies graze.

The ecological impacts of feral horses in places such as the American West, Canada, and Australia are the source of contentious debate, and overpopulation is a concern on more than a few ranges. Thus there’s definitely been interest on the part of biologists and land managers alike with regard to whether native predators might exert some kind of natural control (with some evidence that, for example, cougars may be able to in certain ecological systems).

But maybe we ought to close this out on a PSA of sorts. As droves of vacationers head for the mountain parks of western North America this summer, that recent footage out of Alberta is a good reminder of the rather terrifying speed of ye olde grizzly bear. It’s often said a charging grizzly can “run as fast as a racehorse.” That may or may not verge on exaggeration, but no question a riled-up silvertip (an old-fashioned but still-sturdy nickname for the grizzly) going full tilt is decidedly swifter than a human being – even a human being strongly compelled by self-preservation.

And grizzlies, needless to say, can be riled-up by multiple situations, not least hikers suddenly encountering a sow and cubs or a bear defending a carcass – or simply people blundering into any old grizz without giving it the courtesy of a proper “Hey, bear!” heads-up.

Unless you’re a mustang, don’t run from a grizzly. The best course of action, in most cases, is to deploy bear spray – and, if that fails to deter the oncoming hulk of fur, teeth and claws, to play dead. You can learn more via the U.S. National Park Service and Parks Canada.

Top header image: Knight725/Flickr