The unlikely love story of an endangered tree and the little bird who eats its seeds

When a little gray bird with black wings flies into a bushy tree on the edge of a steep mountain slope, ecologist Alana Clason scrambles to find her binoculars. It flits away, a darting shadow against the glacial green backdrop of the lake at the bottom of the valley. She examines the tree as the bird screeches from somewhere nearby.

“Oh, yeah, there’s little conelets,” she says, excitedly. “Hopefully it’ll come back and hang out.” 

Clason studies mountain ecosystems and leads an extensive, complex restoration project in northwest B.C. focused on protecting whitebark pine, an endangered tree species. Between climate change, deforestation, competition from other tree species and an invasive fungus called blister rust, whitebark has been in decline for over a century. It’s the only tree in Western Canada on the federal list of endangered species. 

“Likely, none of the causes of decline can be reversed,” the tree’s assessment by the Committee on the Status of Endangered Wildlife in Canada states grimly. “The effects of mountain pine beetle, climate change and fire exclusion will increase the decline rate further.”

But scientists working to save the species from extinction are far from defeated. Studying the bird — a member of the corvid family called Clark’s nutcracker — is one part of figuring out how to keep the tree around for generations to come. 

“The nutcracker is the only dispersal agent for whitebark,” Clason explains. Unlike most trees, which spread their seeds on the wind, the scraggly pine can’t reproduce without the bird or other wildlife first freeing its seeds from the cones. She lowers her binoculars and listens to the bird’s distinctive call.  

“What’s cool about it being here, is it means there were enough cones and seeds to keep it around — something is good about this spot.”

Suddenly, a huge bald eagle swoops low over her head and soars down into the valley. Smiling, she stows her binoculars and finishes what she came here to do: check on a camera trap and its audio equivalent, an autonomous recording unit, or ARU. The camera is broken. She says the culprit is likely a curious bear.

“We set this camera trap up to capture whichever critters were coming by and it looks like somebody thought it’d be fun to pop it open and have a chew. Bears love to eat cameras, apparently.”

Bears also love to eat whitebark pine. 

Like the little nutcracker, grizzly and black bears have an affinity for the tree’s nutrient-rich seeds. Clason says documenting connections between wildlife and the tree does a couple of things: the data contributes to the science that guides restoration work and the photos and audio help researchers tell the story of how the tree fits into the ecological landscape.

“We’re trying to document who’s using these ecosystems because we’re always trying to make the case that whitebark pine is a keystone species all these other wildlife species need,” she explains. 

A keystone species, as first defined by Robert Paine in the 1960s, is one that maintains the balance of an entire ecosystem. Without that species, the ecosystem either disappears or is dramatically and irreversibly changed.

Snow crunching under her feet as she heads back to the helicopter waiting in a clearing a few hundred metres away, she scans her surroundings, watching for more birds, and thinks about whether or not to mark the site on her list for seed collection. 

If selected, technicians and tree-climbers will come here next spring to set up cages around the cones at the tops of the trees so squirrels and nutcrackers can’t eat the seeds inside. Then, later in the year, they’ll come back and collect those cones. If everything goes to plan, they’ll eventually have viable seeds that will turn into little trees which they’ll plant somewhere in the mountains nearby. Hopefully those trees will take root and spend hundreds of years supporting an intricate and extraordinary ecosystem.

The birds and bears may have once been whitebark’s only means of reproducing. But now, humans are part of the process, too. We are just as responsible for its survival as we are for its decline. 

Amid the pressures of a changing climate, scientists work to save species ‘without perfect knowledge’  

The fight to save the tree from extinction is urgent work, but it’s unfolding on a long timescale. Whitebark lives mostly in the subalpine, where everything grows slowly. It takes years to know if a seed has a special genetic trait that is needed to make it resistant to blister rust. But because the climate is changing quickly, scientists can’t wait.

“Inevitably, we have to make decisions without perfect knowledge,” Clason says. “We have a lot of science, we have a lot of modelling, we have a lot of things that can really help us make good choices. But we also have to be comfortable that sometimes we’re going to get it wrong. And we need to give ourselves the OK to make mistakes in trying new things.”

Clason and her team at the Bulkley Valley Research Centre, a science-focused non-profit, are experimenting with planting seedlings in a variety of ecosystems. She’s put trees in the ground at the local ski hill, on the edges of wetlands, in sediment-rich soil below glaciers and in areas impacted by fire, like Tweedsmuir provincial park, where a 3,000-square-kilometre burn laid waste to the landscape in 2018.

Months earlier, on a sweltering hot summer day, Clason sat outside a coffee shop in the small mountain town of Smithers where she lives and talked about her plans for the field season. The stress of managing so many moving parts — floatplanes, helicopters, funding, a team of planters, the seedlings at the nursery, government permissions and more — was keeping her awake at night. Because, as if that wasn’t enough, she also had to figure out what to do in the face of a freakishly warm spring. 

Northwest B.C. was hit with extreme heat in May, starting a drought that lasted months and setting the stage for hundreds of uncontrollable fires, what would turn out to be the worst wildfire season in B.C. history. There’s a sad irony to drought impacting the planting schedule. Because whitebark pine lives on the edges of the alpine, where snowmelt and glaciers feed entire watersheds, it plays a vital role in stabilizing the soil and preserving the hydrology of creeks, rivers, valleys, forests and more — everything below.

Clason sipped her coffee and said all her meticulously organized plans were now in question.

“We have two options: plant now when it’s dry and hope for rain or wait until September. But if there’s no rain, the sites will be drier and dustier and go straight to snow,” she said. She added tree-planting is typically done in the spring and summer, per current forest management practices, but in the current and unpredictable climate she wondered if pushing against that entrenched way of doing things might be worth the inevitable friction.

“I think it’s the right thing to do but I don’t freakin’ know,” she said, sighing.

Just a few years ago, Clason wasn’t the one who would be making the decision. Under the guidance of Sybille Haeussler, a forester and ecologist who worked tirelessly on whitebark for decades, she supported the restoration work throughout the northwest, first as a master’s student and later as something of a protégé to the senior ecologist. She once deferred to Haeussler’s deep knowledge and experience, especially in moments like this. Now, with Haeussler retired, the weight of difficult decisions rests on Clason’s shoulders.

Every tree that fails to take root stacks the odds against the survival of the species. Despite its federal status as endangered, whitebark pine doesn’t have full immunity in B.C. — yet. Forestry, fossil fuel and mining companies can still get permits to cut down the trees. They’re not being logged for lumber. Whitebark is usually harvested to make way for roads or other industry infrastructure like pipelines.

Charlotte Dawe, a conservation biologist with the Wilderness Committee, a B.C.-based non-profit, says not only should whitebark be protected from all harvesting, there also needs to be more government guidance on replanting.

“I don’t think it’s a shift that the general public needs,” she says. “It needs to be a mandated legal change.”

“There could be something on the horizon,” she notes, cautiously nodding to an ecosystem health framework announced by the province this fall. 

She adds it’s important that restoration work takes a holistic view and isn’t just about peppering the landscape willy-nilly with seedlings that may or may not survive. 

“It needs to prioritize ecosystem health and community health, first and foremost,” she says. “What are we restoring for? The priority needs to be Indigenous food and medicine plants, biodiversity, species that are at the brink of extinction. If it’s in a critical habitat area that whitebark pine can live in, let’s replant for whitebark pine.” 

A few days before crews were scheduled to fly out to the chosen planting sites, Clason pulled the plug. 

“I’ve just made the call to postpone the whitebark planting until September,” she wrote in a text to me. “There’s a bit too much stress and uncertainty with fire and access to resources.”

The plan to save B.C.’s whitebark pine could prove a model for threatened species around the world

Clason isn’t the only one worried about how climate change is impeding efforts to save the endangered tree.

Diana Tomback, a professor with the department of integrative biology at the University of Colorado and co-founder of Whitebark Pine Ecosystem Foundation, a U.S.-based non-profit with a sister organization in Canada, says the entire community of researchers working to save whitebark ecosystems is increasingly concerned about fire and drought. 

Her doctoral research in the 1980s established the connection between Clark’s nutcracker and whitebark, a “discovery” she’s quick to put quotation marks around, noting Indigenous Peoples across the continent have always known about the relationship between the bird and the tree. She describes herself as being at the “senior end” of her career but hearing her talk about her work is like listening to a young student embarking on a lifetime of studies. Her excitement and seemingly endless curiosity lifts in her voice.

“My research has been sort of schizophrenic in that it is both the tree and the bird,” she says, speaking over the phone from her office in Denver. 

Her early research was in California’s Sierra Nevada range, which she says was relatively blister rust-free at the time, but when she got the position in Colorado, she quickly realized how threatened whitebark was, as the insatiable fungus was spreading through the Rocky Mountain forests. 

“At that point, I would say people were worried about fire suppression,” she says, noting whitebark is one of the first tree species to re-establish in fire-disturbed landscapes. “Now we’re worried about too much fire. It’s really done a 180 with drought and climate change. We’re all worried about climate change. And climate change is what’s making northern latitudes more favourable to blister rust survival.”

To complete its life cycle, spreading its spores and infecting the tree, blister rust requires two hosts. In northwest B.C., the alternate hosts are often mountain wildflowers. It’s a strange juxtaposition: picture an alpine meadow filled with bright cheerful wildflowers — except those flowers are unwittingly facilitating the death of a species. As temperatures continue to warm, those picturesque flowers have a longer season to stay in bloom and spread the disease to the trees. In Asia, where blister rust comes from, trees evolved over thousands of years to coexist with the fungus but here only a fraction have that built-in defence.

Tomback says what’s happening with whitebark reflects a global problem, where invasive species continue to wreak havoc on ecosystems. It’s an issue that the Intergovernmental Platform on Biodiversity and Ecosystem Services describes as “underappreciated, underestimated and often unacknowledged.” 

According to a new report from the organization, “more than 37,000 alien species have been introduced by many human activities to regions and biomes around the world. This conservative estimate is now rising at unprecedented rates.”

Tomback is very aware of this.

“We’ve had waves and waves of exotic disease come in and change our forests,” she says, and adds the reverse is also true. “We have pests and pathogens from everywhere else and everywhere else has suffered from pathogens from North America.” 

She gives the example of the American chestnut, which is deemed functionally extinct in the wild. The tree, a valued resource by humans and wildlife alike that once numbered in the billions, was all but erased from the landscape by a pathogen introduced during colonization. She says the method employed by whitebark ecologists of finding rust-resistant trees to cultivate genetically stronger seedlings could have been used to slow and maybe even reverse the American chestnut’s decline. It can also be used as a model for other species facing a similar plight today.

“They developed this way back in the ’50s, where they realized there were a tiny percent of individuals that actually had resistance to the disease and thought, ‘Hey, why don’t we use them to breed resistant individuals?’ Well, that might have been possible with the American chestnut, but people really didn’t come together on that.”

The reason? The technique was being used for species with significant commercial value, not trees like chestnut and whitebark.

But Tomback says the risk of waiting too long to act on species decline, or take preventative measures to control the spread of invasive pathogens, isn’t limited to biodiversity loss. It’s also an economic issue.

“It costs us hundreds of millions of dollars each year battling these things,” she explains. “We’ve got whitebark listed under the Endangered Species Act and it’s going to cost a pretty penny to both the Canadians and the Americans if we want to make things right.”

‘The centre of a web of life’

While governments on both sides of the border are now actively working on whitebark restoration, it wasn’t easy to capture the imagination of the public and officials. Whitebark pine isn’t very sexy in and of itself. Clason likes to describe it as an upside down toilet brush. Convincing people to care about its survival posed a hurdle for researchers. That’s where the handsome little bird and its ecosystem buddies, the ever-charismatic bears, come in.

“It’s very hard to get attention to plants,” Tomback says. “The best we can do is point out that whitebark pine is the centre of a web of life, a very important web of life. It’s nutcrackers, squirrels and black bears and grizzly bears, not to mention a whole lot of plant species that are found along with whitebark.” 

“And not only that,” she adds, “if you look at whitebark across its range, the ecosystems are so different. You can have sagebrush understories and grasslands and, up your way, you’ve got heather and lichens, a more boreal type of understory.”

In all of these different ecosystems, the prolific bird is the one making sure a mature tree can make baby trees. When a nutcracker extracts seeds from whitebark cones, it doesn’t just eat them all — it saves some by hiding beakfuls in little ground caches. Some of those caches are left, or forgotten, and grow into multi-stemmed trees, strange bushy clumps that look like they have more than one trunk. Tomback notes they have a fascinating characteristic.

“A lot of people consider them the same tree,” she says. “Well, we were the first to show genetically that each trunk is a different genotype — a different individual — that came out of nutcrackers caching more than one seed in a cache.”

That knowledge is vital to understanding how to keep the tree on the landscape. Many ecologists, Clason included, are testing out direct seeding to mimic nutcracker behaviour. Maybe there’s a chance that those multi-stemmed, genetically diverse trees stand a better chance of survival in the face of so many threats.   

But, while researchers now know nutcrackers cache seeds in this way and are exploring what that might mean for future whitebark restoration work, there is still a long list of unanswered questions. It’s the questions that keep Tomback engaged after all these years.

“Understanding the movements of nutcrackers is very important, particularly in the north,” she says. “We would like to understand when they are caching, what circumstances contribute to that caching and is there anything we can do to help?”

‘Spiral’: as whitebark pine declines, nutcrackers may abandon the ecosystem

There’s another, often unspoken, question looming over all this research: what happens to all these species if whitebark goes extinct?

Taza Schaming studied Clark’s nutcracker and its relationship to whitebark pine for her doctorate at Cornell University and works as a wildlife ecologist with Northern Rockies Conservation Cooperative, a small non-profit based in Jackson, Wyoming. 

On a call from her current home in upstate New York, where she’s taking some time to be close to family and raise her young daughter, she says she’s been working on tracking bird movements in the Cascades Range and throughout the Greater Yellowstone Ecosystem, an 89,000-square-kilometre area.

“We performed over 3,000 occupancy surveys in those first few years and now we have an array of acoustic recording units out recording from dawn to dusk, every day, all year round, looking at occupancy of nutcrackers in relationship to habitat,” she says.

Schaming speaks quickly, every sentence densely packed with information.  

“I’ve been looking at habitat use and selection, movement patterns, emigration patterns, social relationships and microhabitat use, foraging behaviour and reproductive behaviour and success.”

She and her colleagues tagged a number of birds with GPS trackers and set out audio traps. She’s now sitting back and watching the data come in. The recording units are trained using artificial intelligence to isolate certain nutcracker calls, providing evidence of use of the ecosystem and documenting the birds’ range. She says she’s seeing movements that suggest the birds are, in some cases, adapting to the decline of whitebark pine.

“We know that they’ll eat seeds from many other conifer species and they’re also super opportunistic like lots of other corvids, like crows and ravens,” she says. “We know that they’ll regularly eat yellow-legged frogs and regularly eat insects.”

That adaptability gives her hope. She says two birds she and her colleagues had strapped little GPS backpacks on made a major change after a rough year for whitebark and ponderosa pine. 

“This fall, all of a sudden, two birds flew to the California and Oregon border. One flew to northern Oregon and one flew to eastern Washington. So we’re finding these birds are moving pretty far. If they don’t have enough food wherever they are, they just go somewhere else.”

“They may come right back the next year to see if the food’s back — or not. We just don’t know.”

“Do I think that nutcrackers can decline to the point of getting … listed as threatened or endangered?” she continues. “Most likely not. They’re pretty adaptable. But there are several ecosystems, several regions, where they may decline drastically and then of course that would lead to this spiral where the whitebark pine wouldn’t have the birds there to disperse their seeds.”

Schaming says doing this work is a privilege but notes it’s incredibly difficult, time-consuming and expensive.

“All of this stuff takes so long, like we go out and collect data and do intensive amounts of field work. For example, right now with these acoustic monitors, we have them set up to record all day, every day, and just getting to one of the monitors to switch out the SD card and the batteries, it’s often a 10-hour hike.”

Even after all the on-the-ground research, which Schaming admits is part of what drew her to the field in the first place, there’s still a mountain of data to sift through before researchers can publish any conclusions.

“Right now, one of the big things I’m working on is we have 10,000 days of audio data and I’m trying to get that data into ones and zeros,” she says. 

Tomback agrees the work is extremely labour intensive and adds so much of whitebark research in northwest B.C. either requires similarly long hours of bushwhacking or the use of the helicopters, which comes with a hefty price-tag. Plus, the rugged and remote landscapes where Clason is working pose an additional barrier to getting good data about the bird. 

“It’s very hard to catch nutcrackers up your way — very, very difficult,” Tomback tells me. At lower elevations, capturing nutcrackers to tag them with GPS trackers is relatively easy, she explains, but in the north it’s a different story. She wants to try and while Clason says it’s been incredibly hard to find funding to support studies of the bird in the north, she would welcome the opportunity.

Planting 38,103 seedlings

Until then, the team in northwest B.C. have their hands full. In September, Clason pulled the seedlings from a local nursery she works with and sent them out to be planted. 

Whanau Forestry, a Smithers-based silviculture company contracted to get the trees in the ground, spent seven days that month planting 38,103 seedlings at four sites around the region. How many will survive remains to be seen.

Jesse Sheffield, a supervisor and crew boss with Whanau, says the whitebark project differs from most of the jobs they take on. Planters are paid day-rates, for example, instead of by tree. And then there’s the locations.

“The planters are excited about getting to go in a floatplane to Tweedsmuir Park,” he says, chuckling. “They aren’t just ho-hum about hopping in the work truck and going to some cutblock.”

While the decision to postpone planting might be bucking the trend, his gut feeling is it was the right call.

“Once you make the decision to lift the trees at the nursery, you’re fairly committed to either getting them planted or else throwing them out, which, obviously, they don’t want to do.”

“In either industry or conservation, you just don’t want to fuck up,” Clason says. “You don’t want to waste the investment. You don’t want to show fault. But there’s risk in just doing things as we always have for fear of failing — we need to be more and more comfortable [knowing] we are going to fail.” 

“We’re not really good at that,” she adds. “We like cookie-cutter. It’s tough, when things are so entrenched and yet the climate is changing, the conditions are changing, the fires are changing.”

Sheffield says he took his canoe along for the planting days in the fire-altered landscape, to help ferry seedlings between several locations along the shoreline of a lake. It’s a dramatic landscape of charred dead trees and blackened soil but he says it’s a place that feels hopeful.  

“The funny thing is, you might think that burned landscapes are inherently more depressing but, at least for myself, I actually find that less draining than always being in a clearcut,” he explains. “We were there for three full days and we’d been there previously, so they’ve got quite a big area planted along the shore of Blanchet Lake now.” 

Because whitebark here, at the northern end of its range, naturally grows in locations most trees can’t take root — dry rocky slopes and exposed bluffs at the edge of treeline — the planters are tasked to slow down and take extra care making sure the seedlings are plugged into the soil where they have the best chance of survival. That’s in contrast to the usual way they work, trying to get as many seedlings in the ground as quickly as possible.

“It works really well to have people who you know are going to plant really good trees and can do the job well in weird and difficult conditions,” Sheffield says. “It’s just a totally different mentality.”

‘Laying the roots of recovery’ for the whitebark pine

If the relationship between whitebark pine and Clark’s nutcracker were a love story, it would be one of true love, at least from the tree’s perspective. Perhaps it would also be an unrequited love story. The tree evolved over millennia to produce the perfect landing pad for the bird, a perch made in heaven. It offers its cones in an open gesture, asking nothing in return. With its seeds greedily plundered, whitebark offspring grow only on a chance that the bird will fly away leaving its secret stash forgotten in the ground.

In a parallel to how the tree brings birds, bears and other species together, whitebark restoration is bringing together academia, non-profits, Indigenous communities and governments. Experts like Clason, Tomback and Schaming continually name-drop collaborators, ranging from lawyers who worked pro bono to help set up foundations, a bevy of -ologists including bear biologists, ornithologists, forest pathologists and, of course, ecologists of all kinds, to allies in governments across North America.  

Here in B.C., Francis Iredale heads up the provincial government’s species at risk program, a department responsible for putting together and co-ordinating restoration plans for species like whitebark.

“It’s like the recipe on how to recover the species based on science [with] inclusion of Indigenous Knowledge and learnings, using the best available information to set the stage for what population recovery would look like,” he explains on a phone call.

Iredale is affable and shares a passion for whitebark ecology with many of the researchers working on the ground. He first encountered the species and learned about its plight while collaring grizzly bears in the South Chilcotin mountains. He says the collaborative nature of the whitebark community is inspiring and he’s proud to play a role in helping connect people and leverage funding to support restoration initiatives and the years of research needed to support the on-the-ground work.

“It’s a matter of just propagating — pardon the pun — those skill sets across the province and sharing how to do things with other individuals and other organizations as awareness continues to increase over time,” he says. “I can help leverage funding to support those necessary acts on the ground.”

At the Smithers-based research centre, adaptability is essential to getting the work done. A few months ago, Ingrid Farnell’s cosy little workspace was transformed into a seed lab.

“This room was like shelves on every single wall and one down the middle,” she says, gesturing. “Initially, we put the cones in trays and we have a dehumidifier that dries them out for about a month.”

A research technician with Clason’s team, Farnell is young and relatively new to whitebark research but is clearly enamoured with the work. Akin to the way Hauessler passed on her knowledge, she has been taken under Clason’s wing and is quickly falling in love with the ecosystem. She says she loves how the research combines fieldwork in spectacular mountain landscapes with intensive data analysis.

After the seeds were fully dried, she and other technicians shucked all the cones by hand, extracting every precious seed.

“You start to feel a little bit squirrely after two months of shucking,” she laughs. “In this whole process, we’re being really careful to not mix up the seeds, to know which trees they came from for genetic reasons.”

She says the Smithers-based team is working on collaborating with the likes of grizzly biologists and have been talking about working with community groups, like snowmobile clubs and other backcountry recreation groups. Pulling up a map of monitoring locations, she zooms in on a mountain range south of the town of Houston. 

“Every time we go to collect seed from the Sibolas, there’s always somebody ripping up on a quad or whatever,” she says. “And they’re always like, ‘Oh, what are you guys doing?’ We tell them and then they get excited about it. It could be a cool partnership where it’s like, ‘OK, can you change the batteries on these cameras?’ ”

Clason says another way the public can help is by tagging a photo of whitebark in the iNaturalist app when they spot one in the backcountry, explaining researchers don’t yet know the tree’s full range.

Iredale, like the researchers, is acutely aware that restoration isn’t going to happen overnight.

“I took my daughter out to the seed orchard and I have a picture of her with seedlings,” he says. “I just reflected, the work I do today is laying the roots of recovery. I may not see some of the fruits of these efforts, it’s the next generations. Recovery is deemed feasible but it’ll certainly take some time. The longer term outlook? I’m hopeful.”

Thinking on the timescale of trees

The helicopter rotors slow to a stop and Clason clambers out onto a rocky ridge. 

Deep in the mountains in an area colloquially known as the Whitesail, she’s monitoring for potential seed collection — and checking to make sure bears haven’t broken the camera trap. She walks along the ridge looking for a small tree so she can examine its cones. 

“Basically what we’re looking for in terms of cone selection is a site with lots of trees and a bunch of them that are really sick with rust,” she says, tossing her words over her shoulder as she confidently strides along the loose rocks. “If there’s any that are healthy, then it’s likely to have some sort of genetic trait that’s keeping them healthy.”

She’s also trying to make sure the trees at this site, and all the others, are likely to have a healthy crop of cones next year. It’s never a given and there’s so much riding on it. She shimmies up into a little tree, reaches for the topmost branch and bends its outstretched crown, where the cones cluster.

After examining the little purple-tinted cones, Clason clambers down and follows her GPS to a small stand of trees perched on the edge of a slope that rises into a dramatic bluff.

“A site like this, which is where you would look for whitebark in the past, I’m not sure whether or not this is going to be a good site for whitebark in the future,” she says, as she removes a memory card from another camera trap, this one undamaged.

She says around five years ago, drought killed an entire seedling site they planted just outside of Smithers, near a popular mountain biking trail. It surprised the researchers, as the site seemed ideal. The loss, which she talks about with an intimacy usually reserved for deep personal loss, taught her a lesson she’s carrying into her work today. 

“I would plant the edge of this gully,” she says, pointing to a depression cutting through the slope. “But I would never plant on the tops of these ridges. You have to find the pocket.”

Clason talks a lot about the need for us to collectively change the way we think about landscapes, ecosystems and the ways in which we inhabit and use those places. Whitebark is just one part of that. 

“As we have more severe and frequent fires, there’s probably not going to be as many trees in some places because of disturbance and also because of the droughts,” she says. “I think the landscape is just going to look different. Humans struggle with change on that timescale and on that magnitude.”

Thinking like this seems to be part of the job description for anyone working on whitebark restoration. It’s as if they’re all somehow able to slow down and think on the timescale of a tree.

Clason gestures out across the wide forested valley and says this dense treed landscape has been like this for millennia. 

“We’re going have to be more comfortable with that changing.”

Updated, Dec. 11, 2023, at 8:20 a.m. PT: A previous version of this story said Francis Iredale studied grizzly bears in South Dakota when, in fact, he worked with bears in the South Chilcotin mountains.

Updated Jan. 2, 2024, at 12:02 p.m. PT: This story has been updated to correct the location of Diana Tomback’s early research, which was in the Sierra Nevada mountains, not the state of Nevada.