Beaver Moon

Two explanations compete and both are plausible. Beavers are conspicuously busy in November, finishing lodges and dams before the water freezes. November was also the last practical month to set beaver traps before the swamps iced over, and beaver pelts were prime — thick winter fur — at exactly this point.

The fur trade explanation carries real historical weight. The beaver pelt was a unit of account in its own right: the Hudson’s Bay Company priced its goods in “made beavers” — a winter beaver skin in prime condition — for export to European markets, where beaver felt hats were an expensive status symbol. The trade ran on that demand for two centuries and began to decline in the 1830s as fashion turned away from the beaver hat.

Frost Moon needs no explanation, and Mourning Moon is sometimes applied to the last full moon before the winter solstice.

Also known as

• Frost Moon
• Mourning Moon
• Digging Moon

The 1778 record

Travelling among the Dakota in 1766 and 1767, Captain Jonathan Carver wrote down all twelve month names in a single passage. Published in 1778, it predates the almanac list by roughly a century and a half and is the oldest independent check on these names.