DNA from fur helps in bear census
Bear populations in Finland and Sweden back at levels of mid-19th century
By Tapio Mainio
Special fur-snagging wires are being used to track bear populations in areas along Finland's eastern border.
The first of the barbed wire installations are to be set soon in the Ilomantsi area near the border. A bear's fur is snagged in the wire when it climbs over or crawls under the fence to sniff at a baited tree stump or log in the fenced-in area. The wood is painted with a mixture of fish oil and blood to attract the bears.
The new method of getting fur samples was announced at an international meeting of bear researchers in Kuhmo in the east of Finland.
"The DNA from the fur makes it possible to specify each individual bear. That is how we will know how many bears there are in the border area", says biologist Alexander Kobatz of the University of Oulu Zoological Museum.
The current estimate of a population of 1,000 bears in Finland is based on hunters' sightings of live bears and their footprints.
In Sweden the size of the population has been estimated on the basis of DNA samples taken from bear faeces. DNA analysis of fur samples is an easier method.
"An estimated 200 bears, most of whom are males, hibernate on the Russian side of the border. It has been possible to follow the movements of individual bears with the help of bear radio-collars", says predator expert Ilpo Kojola of the Finnish Game and Fisheries Research Institute. Kojola is also the director of Kobatz's research.
The official wintertime bear population is 800, because of the roughly 200 who are believed to prefer Russia for their hibernation. The Finnish bear population grew slightly from the previous year.
Researchers would also like to know why there are fewer female bears in the forests of Central Finland than in eastern areas.
A total of 50 fur sample stations are being set up near the border along a distance of about 100 kilometres. The installations will be away from human habitation.
The population will be monitored for three years, while switching the bait every now and then.
The aim is to attract the bears to an area of about 100 square metres surrounded by barbed wire set up about half a metre above the ground.
"There have been good experiences from the fur-snagging stations at a national park in Montana in the United States. Only large bears can leap over a wire set at half a metre, and even then, some hair is left there", Kobatz says.
The recipe for the fragrant bait comes from Canada.
Counting the bear population with any degree of accuracy is difficult, says the Norwegian head of the Nordic bear research project, Professor Joh Swenson.
The researchers have placed radio collars on 500 bears in Sweden in the past two decades.
"People will often see the same bear in different locations, because a bear can easily travel 20 kilometres in a day. A male bear can go even farther", Swenson says. This means that it is possible for a single animal to be counted several times.
With the exception of Norway, the bear population in the Nordic Countries has returned to the level where it was in 1850. At that time, Sweden had about 2,000 bears, and Finland had about 1,000.
"In 1850 there were more than 3,000 bears in Norway, and now there are about ten. A bear population can be completely wiped out by hunting. This nearly happened in the 1940s in the other Nordic Countries as well", Swenson says.
The allocation of bear hunting permits requires more precise information than before on the behaviour of bears.
The latest research indicates that mother bears sometimes bring their cubs close to human habitation for their own protection, because a male bear in heat will sometimes kill cubs. Most recently, a weaned cub about a year old wandered into the yard of the Imatra Spa earlier this month.
Helsingin Sanomat / First published in print 12.6.2006
TAPIO MAINIO / Helsingin Sanomat