Quite the impressive carnivore lineup lives in the Greater Yellowstone Ecosystem in the U.S. Rockies, and sitting on top of its dominance hierarchy, mostly undisputed, are the grizzly bear and the grey wolf. The balance of power between these two – the one bringing great size, strength, and irascibility to the table, the other enjoying strength of numbers and team-player coordination – may tilt one way or the other depending on a given situation.

An example of a run-in going in the wolf’s favour was caught on film this past October. Adam Brubaker, who guides in the Greater Yellowstone with his company Tied to Nature, captured the footage in the northern Hayden Valley, a broad basin just about in the heart of Yellowstone National Park.


In a roughly three-minute clip Brubaker posted online, a good-sized grizzly bear is seen eyeing wolves of the large Wapiti Lake Pack in the Hayden’s sage-strung grassland. (The Wapiti Lakes wolves, by the way, grabbed headlines last March when they made an extended cameo – interfacing with some bison in the process – on Yellowstone’s Old Faithful webcam.)

The bruin rears on its hind legs to nab a better look, then works its way toward the milling-about wolves (to the audible consternation of onlookers watching alongside Brubaker). Once the canids spot the griz, they rush out to confront it. Finding itself surrounded, the grizzly wheels about in a vain attempt to face off the pack, but before too long the darting in-and-out wolves usher the intruder off in a rolling rout. The video ends with the grizzly taking refuge in lodgepole timber, watching the wolves as they cluster together with wagging tails – looking something like a puffed-up football team that came out on top of the scoreboard.

Douglas Smith, Yellowstone National Park senior wildlife biologist and head of the Yellowstone Wolf Program, told East Idaho News that the ravens that can be seen flapping about in Brubaker’s reel suggested there was likely a wolf kill in the vicinity, and he suspected the grizzly was attempting to usurp the carcass. Grizzlies often successfully pirate kills from wolves, but a pack rarely yields without some resistance – and, furthermore, wolves will also readily try to pilfer meat from bears.

“The footage depicts ‘classic’ wolf-bear interaction behaviour and is not uncommon to the two species,” Smith said in the article. He noted that such encounters tend to be a matchup between the grizzly’s superior strength and the wolves’ superior numbers and speed, but – as in this incident – aren’t often actually violent. Such routines “are almost ‘ritualized’ or perfunctory,” he said. “Meaning the wolves – like mosquitos – are just harassing the bear out of an area they don’t want it to be.”

In an email, wildlife biologist Jen Feltner, a PhD candidate in the University of Montana Wildlife Biology Program whose research includes work on inter-carnivore dynamics in the Greater Yellowstone, told me she had a similar assessment of the Hayden Valley encounter. “A grizzly bear is a major threat to wolves, even if there is a pack of them, so they will work together to escort the bear out of the area,” she said. “Attacking the bear directly would be very costly, as the bear can still do a lot of damage to individual wolves, including killing them, which the bear recognises. So even though it’s an aggressive encounter, it’s a pretty calm affair. The bear may still be unsettled though, especially if it’s very hungry and needing resources prior to denning.”

While snorfling down plenty of plant matter, Yellowstone grizzlies are more carnivorous than many brown-bear populations; meat may compose as much as 80 percent or so of the diet of some male bears (boars). In addition to reflecting the sheer diversity and quality of animal protein in the ecosystem – from army cutworm moths, ants, and cutthroat trout to big ungulates such as elk, moose, and bison – that significant meat quotient partly stems from the ready availability of scavengable wolf kills.

Large boar grizzlies can often usurp or defend a carcass from a wolf pack. Check out, for example, this footage from late December 2019 – a time of year when most bears are holed up in winter dens – of a big grizzly refusing to budge off an elk carcass despite facing more than a dozen members of the Junction Butte Pack:

A few months ago we posted about a heavyweight boar grizzly, No. 791, bringing down a bull elk in the Yellowstone River where it flows out of the Hayden Valley. The grizzly held his ground – exercising the classic protective strategy of snoozing right on top of the expired elk – even as wolves checked out the bounty:

No. 791 didn’t end up keeping ownership of his river-killed elk, though, as Feltner noted to me.

“791 that killed the bull elk in the Hayden Valley had no problem defending his kill from wolves, but then he lost it to another big grizzly that was several years older than him,” she said. “In that case 791 may have been more satiated, but the age and experience of the older bear can translate into more ‘confidence’ that allowed him to successfully steal the carcass. Individual animal ‘personalities’ are being studied more and it’s important to recognise that there is a lot of individual variation in behaviour among members of the same species.

Female (or sow) grizzlies with cubs in tow are generally probably less likely to challenge wolves over a kill, given the risk the canids pose to their offspring. A 2004 report co-authored by Doug Smith as well as Yellowstone’s senior bear biologist Kerry Gunther summarised observations of sow grizzlies and cubs interacting with wolves in Yellowstone. In one case, a sow and two cubs did manage to claim an elk carcass from six wolves (of the famed, bygone Druid Peak Pack) in the Lamar Valley. But the majority of encounters at carcasses saw wolves displacing the grizzly families, and in two separate cases evidence suggested wolves killed grizzly cubs in the vicinity of a carcass. (In 1989, according to The Wolves of Denali, a dozen wolves of the East Fork Pack in Alaska’s Denali National Park and Preserve were seen running down and killing two yearling grizzlies despite their mother’s defensive efforts.)

All things considered, it’s a bit of a back-and-forth relationship between Greater Yellowstone grizzlies and wolves, though the bears basically seem to mostly benefit from the relationship given all those wolf kills littering the landscape. Other carnivores in the ecosystem tend to be subordinate to grizzlies and wolf packs. Black bears are enthusiastic scavengers (and hunters in their own right of ungulate calves and fawns), but tend to avoid both wolf packs and grizzly bears; their ability to scramble up trees to escape both of those carnivores likely explains why they stick close to the woods in Yellowstone. Some research out of the Greater Yellowstone indicates black bears are more active in the daytime in landscapes shared with male grizzlies, perhaps because in this region grizzly boars are out and about more at night.

Pumas – superb and brawny hunters though they may be – also usually come off second-best against the much larger grizzly and the pack-hunting wolf. Research from the Panthera Puma Program suggests that across much of both their North and South American range, mountain lions exist as “subordinate apex predators,” generally dominated by grizzly and black bears, wolves, and jaguars. And a Panthera-led study just published in the Proceedings of the Royal Society B showed that competition from wolves appears to be the main limiting factor on puma abundance in the southern Greater Yellowstone Ecosystem.

“These results were surprising,” Dr. Mark Elbroch, director of the Panthera Puma Program and one of the study’s authors, said in a press release. “While puma populations clearly mould themselves around wolves, no one would have predicted that wolves curb their numbers more than human hunting.”

This points up the importance of studying how large carnivores influence each other against the inescapable backdrop of humanity’s pressures on ecological systems. “Dynamics in the large carnivore guild are complicated and fascinating and we are really beginning to learn a lot about how they coexist and balance tradeoffs between acquiring prey resources and risk of competitive encounter,” Feltner said. “Things like resource availability, habitat heterogeneity, and carnivore hunting style all affect whether carnivore guild members are able to coexist. Of course, we usually find that humans do things to upset the natural balance, which is why I think studies of large carnivore competition are so important as human impacts continue to increase.”

Let’s bring this back specifically to wolves and bears to close things out – but only to delight and/or terrify you with this news from Hokkaido, Japan of “robot wolves” being used as scarecrows – complete with moving heads, glowing eyes, flashing tails, and some demonic sonics – against crop-marauding brown bears. Take notes for next year’s Halloween display.