The beaver is starting to push back against the bear in the debate over who controls the top of the world.

Federal officials have confirmed that Canada's Arctic mapping flights have ventured beyond the North Pole into areas claimed by Russia. The flights are the first step towards building a case that Canada's Arctic sovereignty could reach past the Pole despite Russia's determination to extend its own northern footprint.

"We are surveying where appropriate to define the outer limits of Canada's continental shelf," Jacob Verhoef, the Natural Resources Canada geophysicist in charge of the project told The Canadian Press in an email.

Canada and Denmark recently completed a series of joint mapping flights from three remote northern airstrips to begin studying the series of undersea mountains and ridges that will determine how the United Nations will divvy up most of the Arctic Ocean.

The flights were originally said to end at the North Pole. But Verhoef now confirms some of those flights continued past the Pole.

"We are also investigating the possible continuity of the Lomonosov Ridge beyond the North Pole and therefore have collected supporting data beyond the pole on some of the flight lines during the recent survey," Verhoef said.

Although Russia hasn't filed a formal claim for those waters leading up to the North Pole, it has made no secret of its intent to do so.

As well, Russia has undertaken a variety of moves that some call sabre-rattling, from announcing the formation of special Arctic army units to the release of a policy document that warns of the possibility of violence over the North's resources.

Still, Russia has consistently promised it would abide by the United Nations Law of the Sea process for settling all claims.

A summary of meeting held last February between Canadian and Russian diplomats said the two countries, together with Denmark, are considering making a joint submission to the United Nations.

But the fact Canada hasn't simply accepted the North Pole as the extent of its claims shows a willingness to play some diplomatic hardball, said Rob Huebert at the Centre for Military and Strategic Studies at the University of Calgary.

"We're not backing off on this one," he said. "We're going to have to wait and see what the Russians do about it."

Huebert adds that neither country must submit claims to the UN until 2013, so there's plenty of time to come to an agreement. Still, he suggests the aerial mapping means Canada intends to bargain from a position of strength.

"The government is acting on its promise not to be intimidated."

Verhoef cautions that the aerial mapping is only the start of assembling a claim.

"The next step is to analyze that (aerial) information and then decide what, if anything, we should do in terms of collecting primary data (ie: bathymetry and seismic) in that region," he wrote.

Aerial mapping, which "reads" the seafloor by measuring minute changes in the earth's gravitational field, must be backed up by extensive actual measurements. To that end, two miniature submarines are slated to be deployed under the ice by spring 2010.

Although much is made of U.S. Geological Survey estimates that the equivalent of 412 billion barrels of oil lie undiscovered beneath the sea ice, jurisdiction over the pole is unlikely to bring a huge resource bonanza.

Most of those hydrocarbons lie just off the coast of Russia. Most of the rest lies on or near continental shelves, which are largely within existing jurisdictions.