It started with the War of 1812 25 cent coins - there are two designs, where one is frosted, and one is colourized but not frosted. This made the Royal Canadian Mint realize that they can make twice as much profit by making varieties in the finish of the coins.
For the Life in the North 25c coin, there is a variety where the large whale is partially frosted and the other two whales are not frosted, and a variety where the large whale is not frosted and the other two whales are frosted.
The third variety comes from the variety where the large whale is partially frosted - the frosting either extends to the small fin below the whale's eye, or it does not.
I can't take pictures right now but hopefully somebody will have good pictures. Maybe an explanation of the varieties can be added to the edge image on that page.