Friday, May 7, 2010
Beaver Dam - world record set by Canadian
OTTAWA, Canada -- Canadian ecologist researcher
Jean Thie used satellite imagery and Google Earth software
to locate a 850 metres (2,800 feet) long beaver dam in a remote
area of northern Alberta, on the southern edge of Wood Buffalo
National Park, which sets the new world record for the Largest
Photo: This handout photo courtesy of
the Wood Buffalo National Park shows the world's
biggest beaver dam. AFP (enlarge
The previous Guinness world record
for the Largest
Beaver Dam was set by a 652-meter structure in Three
Forks in the US state of Montana.
Average beaver dams in Canada are 10 to
100 metres long, and only rarely do they reach 500 metres.
North American beavers build dams to create
deep, still pools of water to protect against predators, and
to float food and building materials.
First discovered in October 2007, the gigantic
dam is located in a virtually inaccessible part of the park
south of Lac Claire, about 190 kilometres (120 miles) northeast
of Fort McMurray.
Construction of the World's
Largest Beaver Dam likely started in the mid-1970s,
said Thie, who made his discovery quite by accident while
tracking melting permafrost in Canada's far north.
"Several generations of beavers worked on it
and it's still growing," he told AFP in Ottawa.
Mike Keizer, spokesman for the park, said
rangers flew over the heavily forested marshlands last year
to try to "have a look." They found significant vegetation
growing on the dam itself, suggesting it's very old, he said.
"A new dam would have a lot of fresh sticks,"
Keizer explained. "This one has grasses growing on it and
it's very green."
Part of the Largest
Beaver Dam in the World may have been created by naturally
felled trees, and the beavers "opportunistically filled in
Thie said he recently identified two smaller
dams sprouting at either side of the main dam. In 10 years,
all three structures could merge into a mega-dam measuring
just short of a kilometer in length, he said.
The region is flat, so the beavers would
have had to build a massive structure to stem wetland water
flows, Thie said, noting that the dam was visible in NASA
satellite imagery from the 1990s.
"It's a unique phenomenon," he said. "Beaver
dams are among the few animal-made structures visible from
Thie said he also found evidence that beavers
were repopulating old habitats after being hunted extensively
for pelts in past centuries.
"They're invading their old territories
in a remarkable way in Canada," he said. "I found huge dams
throughout Canada, and beaver colonies with up to 100 of them
in a square kilometer."
"They're re-engineering the landscape,"
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Friday, May 7, 2010