Capturing bears for research can cause significant harm: study
The Canadian Press
Article online since August 19th 2008, 0:00
Wildlife biologists are sometimes harming the animals they study with
commonly used research methods, says a new paper already causing heated
debate in the scientific community.
Bears that are captured, examined and then released are left with
lingering muscle damage and long-term weight loss that increases with
the number of times they are caught, said Marc Cattet, a University of
Saskatchewan biologist and veterinarian who is the lead author of the
paper in the August edition of the Journal of Mammalogy.
"It's been a common misconception that the capture and handling of
animals has short-term effects on animals but is unlikely to have any
long-term effects," he said Tuesday.
Cattet used data from two different bear research projects - one in
Alberta on grizzlies and one in North Carolina on black bears. Both
projects used padded leg-hold snares, barrel traps and helicopter
darting to capture bears and collect data on their health and movements.
Cattet and fellow researchers used that data to analyze the bears' blood
for enzymes that are released by muscle damage during extreme exertion,
struggle and stress.
About 70 per cent of the grizzlies captured by snares had higher than
normal levels of such enzymes - in some cases up to 12 times higher.
Levels were also high in nearly one in five of grizzlies darted from
helicopters and in 14 per cent caught in barrel traps.
Black bears also had high muscle-damage enzyme levels in about
two-thirds of those caught in snares and one-third of those trapped in
"We'd be damned sore if we were subjected to those kinds of procedures
and if we had these levels of enzymes," Cattet said.
Stiff and sore, the bears move around their territory less. The study
shows grizzly movement dropped almost in half and black bears roamed 25
per cent less, with the effects lasting for up to five weeks.
That disruption seems to have long-lasting consequences. The weight of a
nine-year-old grizzly captured three times averaged 14 per cent lower
than normal, an effect that increases with the number of captures.
Recapture is a common research method. About a third of the grizzlies in
the study had been recaptured up to eight times.
The effects of weight loss may linger into the next generation. Research
in polar bears suggests underweight sows deliver underweight cubs.
Although Cattet's research focused on bears, there's no reason to
believe the findings wouldn't apply to other mammals commonly studied
through capture and release, such as caribou, he said.
"We're all mammals. We're all built of the same materials. We function
in the same way. It's a no-brainer."
Cattet points out that not only does capture-and-release harm animals,
it distorts data scientists are in the field to collect.
"There's a good chance that what you're doing may actually affect your
However, capture-and-release is a standard and necessary study method
because it's the only way to get certain information. It's deeply
engrained in wildlife biology and Cattet said he's already experienced
resistance to his conclusions.
"There will be people that will embrace it," he said. "On the other end
of the spectrum, I think there's going to be some hostility, too.
"For some people, it's going to be perceived that this paper is a direct
affront to their way of life and it's not going to be received well. I
know from discussions over the past three to five years some people just
don't want to hear it."
Even getting his paper published was a struggle, he said.
"In the review process there were some individuals that just didn't want
Northern aboriginals have also raised concerns about wildlife research
Last December, Nunavut Tunngavik Inc. - the group that oversees the
Nunavut land claim - passed a unanimous resolution calling on the
federal and territorial governments to stop all wildlife research that
involves excessive handling of wildlife.
Response by Jessica Teel
Great article to share, thanks Brenden. This confirms what I have
always suspected - that capturing animals for research negatively
impacts the animal. This article doesn't mention the practice of
extracting teeth from captured bears, which - duh, how could that not
effect your feeding habits. It seems that in so many cases research is
merely to satisfy human curiosity - and so much research never, ever
helps the animal and is motivated by scientists wanting to gather data
and publish papers on it. Given that any data that does not fit into
game and fish policies is disregarded, you are left with damaged bears
and only research that supports the status quo which means keep enough
animals alive so we have some to shoot for fun. I for many years have
thought that capture and relocation of "problem" bears contributes to
the likelihood of bear aggression towards humans. I saw this play out in
a fatal mauling in Canmore, Canada when I lived there. A benign bear
that did not harm humans in close range was relocated twice, and then he
mauled a jogger. Before the relocation he was not aggressive towards
humans in the area.
The years of Denali wolf studies often had fatal consequences -so
much so that their data had a statistical column devoted to fatalities
caused as a result of darting the wolves. I hope researchers take
seriously what this article has to say.