While most fur bearing animals in Alaska are skinned whole and stretched long, beaver are split down the belly and stretched round.

Trappers make a beaver board of several planks nailed together. They draw circles on the beaver boards to show where to stretch the skin in order to keep the round shape and get top dollar for the fur.

Beaver Boards
Beaver Boards
Henry couldn't figure why a superblanket beaver (very large) was worth so much more than a blanket. He figured that there was only a few inches difference between the 68" superblanket and the 60" blanket beaver.

 These measurements represent the sum of the length plus the width.

When he took high school math he realized. The area of a circle is equal to pi (π)times the square of the radius.

A=r 2

when =3.14

A radius that is a little larger gives a much bigger area because the area is determined by the square of the radius.

How many square inches of fur are in a 60" blanket beaver?
Watch out! 60" is the sum of the diameters, length plus width, not the sum of the radii. First find the radius of the beaver skin.
How many square inches of fur are in a 68" superblanket?

He used to think the fur buyers were cheating him on his blanket beaver. After doing the math, he realized that there is a big difference in the area of a blanket and the area of a superblanket beaver.

Beaver BoardsBeaver skin stretched on
the smokehouse

Beaver Boards

Ask the elders in your community how they made a compass to draw the circles on a beaver board.


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