Research team looks at humane darting of grizzlies
By Kristina Bergen
U of S veterinary experts and their colleagues in the Northwest Territories have teamed up with RCMP forensic scientists to find better darting techniques for immobilizing grizzly bears and other wildlife.
The U of S-led team has found that some darts cause significant long-term injury to bears. Though field research and animal capture are necessary for the long-term well-being of grizzlies and other species, the team says safer darts can lessen the impact on captured animals.
The search for more humane darting is an offshoot of work by U of S researchers in the Foothills Model Forest grizzly bear research program, which recently won an Emerald Award for Environmental Excellence. They include Vice-President, Research, Steven Franklin, whose team uses remote sensing to study bear movements, and Marc Cattet, a wildlife health specialist with the Canadian Co-operative Wildlife Health Centre headquartered at the Western College of Veterinary Medicine.
“Many of us have long assumed that capture and handling only affects bears for a short time,” says Cattet.
“We believed that as long as the animal got up and walked away, everything was going to be fine.”
That belief was challenged when data on grizzly movements showed that bears slowed down for about a month after capture. And grizzlies captured more than once were usually in poorer condition than bears captured for the first time.
Having previously seen bear remains where the animal died from a severe dart injury, Cattet and U of S veterinary anesthesiologist Nigel Caulkett suspected dart injuries might be one of the factors slowing the bears down.
They joined N.W.T. Wildlife and Fisheries veterinarian Brett Elkin and conservation officer Albert Bourque and headed to the RCMP Forensics Lab in Regina, where Dean Dahlstrom and Kramer Powley – both former U of S wildlife biology students turned forensics experts – helped prove that certain darts are harming animals.
The team tested a range of darts by shooting them into ballistics gelatin wrapped in elk hide to simulate muscle, fur and skin. Each shot was captured by Doppler radar chronograph and digital video. Similar tests were also done on calf carcasses.
“Once we ran these tests, we were amazed at the amount of damage that can be caused by a single dart,” says Cattet. This damage often goes undetected in a living animal because it is concealed by skin and fur.
Some darts are worse than others. One dart causes injury with a small detonation used to explosively force its drug payload into animals. Then, as the needle penetrates it forces along a core of skin and hair that can fester and cause infection; the barbed tip also works like a fish hook to pull skin from underlying tissue.
A safer dart uses air pressure to force the drug into an animal, and also releases the drug from a hole in the needle’s side. A solid tip doesn’t core the animal’s skin or force the drug deeper into muscle tissue. With less damage and a smaller wound, the animal is likely to recover sooner.
Cattet says a number of dart companies want to improve their darts and are providing strong support for this research.