A Canadian-based ecologist says he has located the world's largest beaver dam in northwestern Canada using Google satellite technology.
Ecologist Jean Thie located the 2,788-foot (850-meter) dam using Google Earth and NASA technology while researching the rate of melting permafrost in the country's far north.
Situated in northern Alberta's Wood Buffalo National Park, which straddles the Alberta-Northwest Territories border, the dam stretches more than eight football fields long, Thie said Friday.
"I couldn't believe it when I saw it — it's a vast, vast area. There may be longer dams out there, but this, by far, is the largest I have seen so far. And, it would not have been possible to view it without something like Google Earth," Thie said.
Thie told The Associated Press the detailed satellite program helped him conclude the dam was the work of beavers — which, incidentally, are the country's national symbol.
Thie discovered the dam in 2007, but he said it only recently caught media attention after someone at a British paper spotted his findings on a blog and ran a story reiterating Thie's claim that the dam is visible from space. Thie stakes that claim because he used satellite technology to detect the dam.
"It might be hard to believe, but there are a few things that are visible from space, and beaver dams are among the few animal-made structures that are," said Thie.
Park spokesman Mike Keizer said the dam sits in a corner of a park "the size of Switzerland" in an area surrounded by heavily forested marshland.
Keizer flew over the beaver dam, but said there was no safe place to land anywhere nearby because it's either overly boggy or the foliage is too dense.
Using past images and park aerial photography, Thie concluded that the eager beavers began their work in the 1970s and that generations of the rodents have worked on it since.
"This was the work of extended families," said Thie, who is the president of EcoInformatics, a science research company.