Grizzlies that feed near rails not necessarily the bears killed by trains, study suggests
Most grizzly bears rarely visit railway tracks, but those that do most often are not the bears that end up getting hit by trains, a University of Alberta study suggests.
"The regular rail users may not be the most vulnerable to being struck by the train, because they learn how to cope with it," says principal researcher Colleen Cassady St. Clair.
"What we think happens with the bears is, the ones that are more vulnerable [to being] struck by trains are the naive animals."
The study, part of bigger project examining the behaviour of bears around railways, looked at scat collected near the railway tracks and data from GPS collars on 21 grizzlies in Banff and Yoho national parks, whose range included the the Canadian Pacific rail line.
Surprisingly the bears' diets varied greatly, St. Clair said in an interview Wednesday on CBC's Radio Active.
While two bears never went near the rails and 15 rarely used the tracks, four bears visited them frequently.
Three of the four were what St. Clair calls "skinny teenagers," sub-adult bears that used the tracks opportunistically to feed on spilled grain.
The fourth bear was the infamous "The Boss," Banff's largest grizzly, well-known for eating deer, elk and moose, St. Clair said.
"He uses the rail to cruise looking for ungulates … and they might also be animals that had been hit by trains," she said.
The study is also looking at how to prevent collisions between trains and bears.
One finding that will published at a later date is that the focus should not be on preventing bears from going to the rail, which would be difficult and prohibitively expensive.
Instead biologists could try to prevent bears from being surprised by trains, giving them the opportunity to get off the tracks, St. Clair said.
"We've been working on a warning device and that news will come, I hope, fairly soon."
Other preventative measures could include reducing how often trains with grain cars stop in national parks and increasing warning times for bears by clearing vegetation giving longer sight lines on tight corners, St. Clair said.
The study was published May 24 in the journal PLOS ONE.
