How can we protect grizzly bears from their biggest threat—trains?

In an area with high grizzly mortality rates, the birth of three cubs in January 2021 was a triumph in Elk Valley, British Columbia.

But nine months later the unimaginable occurred when the family of cubs and their mother were killed by one of the grizzly’s biggest threats in the region: trains.

“She was one of the only grizzly bears we had ever monitored that actually produced three cubs,” says Clayton Lamb, wildlife scientist at Biodiversity Pathways, a research institute at the University of British Columbia. “It was a big loss.”

For decades, portions of the Rocky Mountain range across the U.S. and Canada have been a lethal stretch for grizzlies where freight trains barrel through protected and critical recovery zones. But recently, the toll has escalated. Since 2008, an estimated 63 grizzlies were allegedly killed by train collisions in northwestern Montana and northern Idaho alone, with a record-high eight bears struck in 2019 and three more in 2023, prompting two conservation groups to sue one of the major railways for violating the Endangered Species Act.

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It might not sound like a lot but in a population that conservationists have worked hard to rebuild, the deaths are a significant setback. However, solutions and initiatives are actively underway to safeguard grizzlies in a changing landscape where humans and bears are learning to coexist. 

A hotspot for collisions

Railways are typically located in secluded, uninhabited areas apart from the chaos of human disturbances, and in the case of the northern U.S. Rocky Mountain range, these tracks plow through vital grizzly recovery zones.

Only about 2,000 grizzly bears roam the contiguous U.S., where they make up two percent of their historical range.

With decades of conservation efforts, however, grizzly numbers have rebounded to 1,100 within the Northern Continental Divide Ecosystem (NCDE), a recovery zone of north-central Montana. This population is growing by about two percent each year, according to Justine Vallieres, wildlife conflict management specialist for The Montana Department of Fish, Wildlife and Parks in northwest Montana.

On the other side of the border, the Canadian province of British Columbia also remains a stronghold for grizzlies despite threats to 60 percent of its grizzly bear populations.

(How Indigenous knowledge is helping to protect Canada's grizzlies.)

Yet grizzly train and road strikes happen more frequently in these northern regions of the Rocky Mountain range. Some areas are more deadly than others.

Elk Valley, for example—a region that only makes up one percent of British Columbia’s 15,000 grizzly range—accounts for nearly half of the province’s recorded bear-train mortalities. It’s also where young grizzlies experience the lowest survival rates recorded in North America, according to a recent study Lamb published.

The NCDE, meanwhile, has recorded 75 grizzly railway deaths since 1975—two-thirds of which have occurred after the year 2000.

So what’s causing it? Grizzlies congregate toward these corridors for several reasons: the abundance of berry-producing shrubs along railway edges and animal carcasses that have also been killed on the tracks which, as Lamb describes, “becomes a cycle of railway mortality that feeds itself.” 

Other factors, though, make the tracks a dangerous site.

A meat magnet

For years, scientists speculated that grain spilling from leaky railway cars was a leading cause of bear strikes. This was certainly the case in Montana when three trains derailed south of Glacier in the late 1980s spilling “10,000 tons of corn in 106 cars along a three-mile stretch of track.”

Colleen Cassady St. Clair, professor of biological sciences at the University of Alberta, believed that grain “would be kind of a smoking gun” when she began investigating the cause of train strikes in Banff and Yoho National Parks.

Yet in the Grizzly Bear Conservation Initiative jointly funded by the Canadian Pacific Railway and Parks Canada, she says, “We just didn't find good evidence that was the case.”

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She believes the uptick that occurred in 2000 within the region was actually due to the sudden decline in elk populations (a main food source that potentially changed grizzly foraging patterns), the near elimination of management killings, and changes in how the carcasses of other animals are disposed.

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Protein-deprived bears cross roads and railways to get to large gravel carcass pits where dead livestock or roadkill are buried—a management strategy that is used all over the world. To combat this issue places in British Columbia have started to implement concrete walls and an electric fence perimeter around these pits to deter bears.

Speed kills

Speed, however, is the largest contributing factor as to why bears are killed in collisions.

“It makes sense because of the laws of physics,” St. Clair says, “but also because there's so much less time for animals to detect an approaching train and get out of the way.”

Collisions tend to occur in areas where trains are less detectable around curving tracks and within proximity to water where the rail provides an easier travel route across difficult habitats. In some regions, grizzlies are especially likely to be hit on trestle platforms where there’s nowhere on either side to escape.

Another common issue is females traveling with their offspring. As Chris Servheen, North American Bear Expert Team co-chair of the IUCN's Bear Specialist Group and president and board chair of the Montana Wildlife Federation explains, when a train comes and a mother and her cubs are separated on either side of the track, there’s enough space beneath the freight for them to see each other.

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“They don’t know that the train will eventually end, so they’re in a big hurry to reunite… but of course, it’s lethal to try to run under there.”

 The mountainous topography also comes with added risk factors.

Locomotives sound louder as they chug uphill but that changes as they descend, becoming eerily quiet—so much so that they sneak up on wildlife.

“There were several occasions where I could see a train before I could hear it,” says engineering scientist Jonathan Backs, who studied the effects of train audibility on wildlife. “I’ll be working on the track, and look up to see a train right there.”

In his study, Backs found that noise from nearby highways also made trains less audible in some locations.

Moving forward

The question remains: is there a solution?

From 2016 to 2017, Backs developed and tested an early detection warning system that emits bell sounds and flashing lights triggered 30 seconds before a train arrives in that location.

A study showed that if the warning system deployed, animals left the track sooner than if it hadn’t been activated.

The system, though, is not currently implemented anywhere.

In north Montana, conservation groups, nonprofits, and state and tribal fish and wildlife departments are working with railways to mitigate some of the underlying causes. But the delayed implementation of formal plans to reduce train-caused grizzly mortalities in the NCDE is at the heart of the recent lawsuits that have been filed.

Meanwhile, scientists and policymakers alike have prioritized studies to address the impact of highway collisions with wildlife over studying railways because road collisions have a greater impact on human lives.

“Railway collisions end up being these silent killers of wildlife in that they occur often away from the public eye,” Lamb says. “It's only the wildlife that loses.”

“I’m keen to work on solutions or dream out new ones and test them,” he adds. “That’s what our science program focuses on: how can you make a difference, implement … and propel forward the interventions that work?”