If you are traveling between Alaska and Canada, keep in mind that the Canadian dollar and the American dollar are separate currencies and the rate of exchange fluctuates daily.
Although U.S. currency is accepted as payment in Canada, visitors should exchange their U.S. currency for Canadian funds at a bank in Canada to receive the best rate of exchange. In the Yukon, businesses participating in the "Fair Exchange" program--which promises an exchange rate within a few percentage points of the banks--post a "Fair Exchange" sign in their windows.
You can check out current exchange rates on the Internet at several sites. One such site is Bank of Canada's Exchange Rates.
Like the U.S., the money system in Canada is based on dollars and cents, but Canada also has the "loonie" and the "toonie." The "loonie" is the Canadian $1 coin, which pictures a loon on one side. The "toonie" is their $2 coin, which has a picture of the Queen on the front with a bear on the backside and is two-toned.