Moonax

Lewis failed to recognize the yellow-bellied marmot as being anything different from the familiar groundhog (woodchuck) he knew from the eastern part of the country.  In fact, he used the archaic name "moonax" or "moonox" for both species.  Moonax came from the scientific name for the groundhog, Marmota monax.  Like the woodchuck, the yellow-bellied marmot is a large, ground dwelling member of the squirrel family, and is one of a half-dozen marmot species in North America, including the groundhog.  Yellow-bellied marmots inhabit rock slides or boulder fields on mountain slopes that are adjacent to lush vegetation.  By contrast, groundhogs prefer forest edges alongside fields, streams, and some man-made open areas.  Also known as the rockchuck, the high-altitude living yellow-bellied marmot has an underside washed in yellow to yellow-red.  Groundhogs have a deeper reddish-brown colored fur over the same area of the chest and belly.

For more information about this North American mammal, click here.